Hyperloop One Becomes ‘Virgin Hyperloop One’ | Hacker News Reader

Hyperloop One Becomes ‘Virgin Hyperloop One’

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364 pointsmpweiher503 comments

The biggest problem people have with Hyperloop is because it certainly seems like Elon Musk just waltzed into the high speed rail debate and Dunning-Krugered some crazy scheme that doesn't look anything at all like conventional approaches to the problem and thus doesn't jive with any common sense we might have built up around different transport methods.

But that's kind of what Elon Musk does: he Dunning-Krugers himself into a new industry every couple of years, using a simplified, undergraduate physics level of analysis to find something that (to an optimistic non-field-expert) looks like a better solution to the problem.

And the most annoying thing of all is that he usually succeeds. Often in spite of his original idea being technically wrong. For instance, Falcon 9 was supposed to be recovered with parachutes... that didn't work, and people who were working on vertical landing rockets told them that, but at the time Elon just rolled his eyes and said "just use parachutes." But SpaceX/Elon found out the idea didn't work and switched to the "correct" solution and got it to work operationally (and with paying customers) much faster than people who had been working on the problem for years before.

The moral of the story is that it's often better to be able to execute fast even if you start out wrong than to take your time with the right answer.

The moral might be that hubris along with billions in cash can accomplish the things the person with hubris set out to do.

Elon Musk didn't start out with billions of dollars, and he has almost no liquid assets (he borrows against his stock when he needs cash).

But this is a good point. Lots of talented people have good ideas that end up going nowhere because of lack of capital for implementation.

He spent all his money on his trio of companies by 2008. He could've relatively speaking for people worth a hundred million to billions, be worth very little today.

I don't think he has ever in his life had a billion in liquid assets. You could argue I guess, but he likely wants to keep a majority stake in SpaceX, and likely doesn't want to go below 20% stake in Tesla.

> Elon Musk just waltzed into the high speed rail debate and Dunning-Krugered some crazy scheme

I think it's incredibly important to segregate Musk's work, i.e. SpaceX and Tesla, from his proposals, e.g. the Hyperloop, modular infrastructure and other things.

Nah, the Dunning-Kruger thing applies equally well to Tesla and SpaceX. He had no experience in either field before starting those companies. It's just that he has, in spite of all probability, succeeded and so you see them in a different light.

Maybe his experience is in building successful companies.

Didn't he actually design the first rocket himself? He's quite smart. I don't think "industry experience" counts for much. By the way you're using "Dunning-Kruger," it's unclear that you actually know what it means...

I think GP could have a point with Dunning-Kruger applying to EM. Here's the main difference IMO: By far most people who experience the Dunning-Kruger effect have no way of self correcting, i.e. they don't recognise when they're wrong or they do when it's too late or they keep on their path nevertheless because of the sunken cost fallacy or vanity. EM on the other hand has proven to be very good at admitting and correcting his mistakes. That filter effect combined with simple uniform-density-spherical-cow type modelling for his initial guesses combined with some of the best computer simulation experts in the world seems to be enough to have catapulted his endeavours to orbit and back - both figuratively and literally.

I just Dunning-Krugered myself about Dunning-Kruger.

>I just Dunning-Krugered myself about Dunning-Kruger.

Ultimately you didn't. That very comment shows you were able to recognize and correct for your mistake in the end.

Perhaps if you insist you've Dunning-Krugered yourself about Dunning-Kruger, then I may agree that you have in fact Dunning-Krugered yourself about Dunning-Kruger.

It's turtles all the way down.

DKE = lowest skilled people think they are a little above average. Low skilled people do not think they are as good or better as a very high skilled individual would be.

Look at the graphs in the actual study:

http://psych.colorado.edu/~vanboven/teaching/p7536_heurbias/...

It's more like the range of 10-90% actual skill is simply transformed to 50-80% perceived skill. The absolute ranking of person by skill order is still accurate.

If Elon Musk is actually at about the 75% percentile of skill which maybe he is, if you turn the graphs that DK reported into a function of actual to perceived skill, if you fed 75% into that you would get like maybe 73%. The real vs. perceived skill curves cross at about 70%.

Versus the popular supposed version of DK, being something like "you are wrong and you do not know it." It's easy to describe the DK to sound like it's a profound explanation of that, but if you look at the data they reported, it's a much more timid effect than it sounds like it is.

To put it another way, low skilled people think they are better than most of the other low skilled people, but they themselves do not perceive themselves to be better than someone who does in fact know what they are doing. Low skill people would think they are a bit above average, not a superconfident expert.

i would very much doubt that. i remember reading an article early on about some russian investors or engineers noting he knew almost nothing and that he was just reading a lot of university textbooks on areospace engineering.

He did do much of the design on the first rocket, which is probably why it blew up 3 times. He was smart and dedicated enough to figure it out eventually, but he totally stumbled into the field completely clueless.

> Didn't he actually design the first rocket himself?

I'm pretty sure there were core employees (not Musk) working on every part of the rocket from the beginning. This is documented in the Vance biography, IIRC.

I think having no experience is an advantage in industries which have become stagnant. If the industry is stagnant, than in a sense, most people in the industry is a failure. I'd compare this to visual programming. There is a small click of people in visual programming who have been at it for decades. They are failures, as none of their projects or ideas have had any value. Taking advice from them is worse than useless.

Edit: I changed what I wrote, so as to not claim that "everyone" is a failure, some people worling in visual programming are still having fresh ideas. But they don't have the attitude of being "industry insiders" the ones with fresh ideas are the least arogant and offputting to outsiders. They are the ones who are least likely to put someone like Elon down as being inexperienced.

That's a rather cynical view of what is essentially him doing dimensional analysis to find out if it's worth putting effort and money into these ventures, and then hiring a bunch of really good engineers to go towards it.

Agreed. I'm a physicist, so feel the same way, but people who are actually experts in whatever field usually hate that... https://xkcd.com/793/ "Liberal arts majors may be annoying sometimes, but there's nothing more obnoxious than a physicist first encountering a new subject."

This is also a good time to introduce the concept of survivorship bias. There's a fair chance that it was mostly luck, not ability, that it ultimately succeeded.

I don’t know there are a lot of people who have crazy ideas and succeed once despite all odds.

Elon Musk did that twice at a very big scale with Tesla and SpaceX. Both companies were supposed to fail and yet the succeeded. And while it is not my generation I believe zip2 and PayPal also had pretty novel concepts which were supposed to fail back then too.

He has just done it too many times to be just luck. Sure there was also a lot of luck, but it takes more then luck to do that with at least two successful companies.

There are far more people who tried crazy ideas and failed, and are promptly forgotten. The whole point of survivorship bias is that you have to be cognizant of the data points that failed and therefore aren't recorded, not just the ones that survived and are recorded.

According to this: https://www.inc.com/leigh-buchanan/us-entrepreneurship-reach... there are 27 million entrepreneurs in the the US. That's a large enough number that even if the chances of each individual entrepreneur having a big hit is just a few percentage points, then there are bound to be many entrepreneur who have multiple successive big hits. Especially considering how many people who are even tangentially related to a successful startup describe themselves a founder or co-founder, resulting in the padding of the success rate.

My point being is that we can't rule out the possibility of it all being luck or mostly being luck. Sure, it legitimately could be skill, but there is no way to know for sure, at least currently.

> "all being luck or mostly being luck"

Seriously? What, he flipped a coin a million times which determined what he's going to do next? How are you defining "luck"?

Not the OP, but the point of survivor bias is that there were 10 million people flipping coins for the first "moonshot" idea, and let's say 1000 succeeded; then those tossed the coin for the second moonshot and only 1 succeeded. Was the one who succeeded so much better than the other 1000, or mostly luckier?

But my point is that he didn't flip thousands of coins. He made thousands of calculated decisions. His thousands of decisions resulted in success. Others, with their own thousands of decisions did not. I don't see the "luck" here.

He took thousands of calculated risks. Lots of those calculated risks didn't pay off, you can be sure. But enough of them did. There are no Übermenschen.

I'm not saying he's the greatest person of all time, or even the smartest, but he's demonstrably one of the best at getting very large high risk projects off the ground and building tons of support for them. That's not luck.

The point is, if enough of people are making decisions, success is not sufficient to distinguish a "calculated decision" from a lucky one.

I get the point, but it's ridiculous. It's like monkeys on a typewriter coming up with Shakespeare. Sure, it's theoretically possible, but the odds are incomprehensibly small based on luck alone. If a monkey did write that prose, it's probably a pretty special monkey. Likewise, Elon is a pretty special monkey too.

I used to think that about Musk, but his successes seem to be piling up. Specifically: Paypal, Tesla, and Space-X all seem to be rather successful.

Wouldn't be so sure about Tesla since it has yet to turn in a meaningful profit. SpaceX is a maybe since we don't know its internal finances. We're also ignoring SolarCity, which by any metric was a failure.

SolarCity failed (and he had to buy it back himself with Tesla), Paypal was a success but it wasn't his, his part was x.com which was kind of a failure on its goal and had to sell (just because it sold for a lot of money doesn't mean it succeeded, in the terms of "success" we're discussing in this thread).

Tesla has yet to make any money and fails to meet its deadline, and it's yet to see how it will far now that the car giants are turning to EV (especially with many countries setting deadline in 2016 and 2017 about the end of non EV cars, which jolted all the big ones into joining).

Space-X is for me his one real success so far, it leaned on a lot of public funding to do it so it's really not the kind of things usual for HN, but they said they would re-use when everyone else said "can't be done" or "not worth it", and they're getting there.

Impress me once, you lucky. Impress me twice, I'll have to talk about survivorship bias.

Impress me four times, and I'll start misquoting Napoleon: "If he's been lucky that often, he's the General I want for this"

In case anybody else was not familiar with David Dunning and Justin Kruger:

"The Dunning–Kruger effect is a cognitive bias wherein people of low ability suffer from illusory superiority, mistakenly assessing their cognitive ability as greater than it is."[0]

[0]: https://en.wikipedia.org/wiki/Dunning–Kruger_effect

..and it's quite the charge to throw at the guy with the first commercial spacecraft and the leading electrical vehicle.

Maglev in a tube is a proven technology at full train scale. Here's the Chuo Maglev from the inside.[1] 500KPH in tunnels. They're not pumping down the tunnels, just plowing through on sheer power and money.

The Chuo Maglev makes the Hyperloop One look like a toy project. Watch the video. They have a production-quality train, with tourists and whiny kids riding it, going 500km/h. They've hit 603km/h in tests, but don't run it that hard normally. This is the first section of track between Tokyo and Osaka via Nagoya. Planned opening to Nagoya is 2027. Japan's Alps are in the way. They're tunneling straight through. Longest tunnel segment is 25km and it's being drilled now. 90% of the Tokyo-Nagoya segment will be in tunnel. Stations in Tokyo and Nagoya are under construction. The line will probably run 3-4 trains an hour each way, like the existing Shinkansen.

Hyperloop potentially has a higher speed to 900-1200km/h, but that may not be achieved in practice. The Chuo Shinkansen has a turn radius of 8km, and passengers don't have to be strapped in. Hyperloop would need 4x the radius to go twice as fast with the same ride quality. Laying out a route with a 24km turn radius severely limits where track can go.

Strapping everybody in and pulling 0.5G sustained is not going to go over with customers. Commercial aircraft usually stay within +-0.25G. Maybe 0.5G in mild turbulence, and customers don't like it.

[1] https://www.youtube.com/watch?v=HZ6dYhHIol8

Amen. If you want a fast train in 2017, hire the people who have been winning in that department since 1964.

Also, the リニア will cut travel time between Tokyo and Nagoya from about 100 minutes to 40 minutes, which is a big difference for people who do business between those two regions.

That's insane. If you didn't have to switch trains for Philly (30th St) to NYC, an avg ride could take a bit than 100 min if there are only around 7 stops the entire way (normal stops would make the ride like 2 hours). Reducing those numbers by more than half would be incredible. Even if this is just a pipe dream and there isn't a direct train between the two cities right now anyway.

I think straight line distance of NYC -> DC is a little further than Tokyo -> Nagoya, but even the current Nozomi Express Shinkansen would be a huge improvement over Amtrak.

Oh wow didn't realize the distance.

Stops and waiting are by far the biggest slowdown in train travel. In a moderately dense area, if you could magically put enough trains on the tracks to offer all important connections as high frequency point to point connections, you would get enormous improvements in travel time even at moderate cruise speed. Tracks are empty almost all the time because trains cannot evade and have very low deceleration, they have to reliably coordinate far beyond visual range. And by reliably I mean more than aviation grade reliability, because there would be no redundancy and no Hudson River to splash into when you mess up that part.

The good news is that it's "just" an information problem (well, so is landing a rocket, in a way), the bad news is that the number of possible endpoint pairs in a network is bloody high.

In the end you get back to the old vision of on demand "pods". I suppose that those could still be made "rail-efficient" if you make them robotically jack into a paceline behind a tender that provides drafting and power grabbed from an overhead line (you would not want this per pod), but run on battery power only to get to/from the tender at endpoints (which the tender and its followers passes non-stop) and when the paceline gets broken by someone exiting. If you can start over on a new right of way, this is what you should do (in a pinch, you could also take over the leftmost lane of existing roads, but that's not a good place for doing construction and maintenance).

I think you can get most of the benefits just from a well designed timetable. I get the impression that's mostly how they make it work so well in Japan.

There tend to be at least local and express services on almost all routes, and often multiple tiers of express. Another common pattern I've seen is having several commuter services which each run stopping for a different section of the route, and then run express to the central stations. This gives passengers the benefits of swapping between local and express services, without them loosing time changing trains.

Of course, all of this is a lot easier when you already have the passenger numbers to support it.

NJ transit does do the minimum of express for the farther out places from NYC. Nothing as in-depth as you're explaining. But as you said. The numbers wouldn't support making things too much more complex. That's why my original post mentioned a limit or 7 stops between philly and NYC as an example of a semi-express train. Though a hypothetical express train would probably actually be 5 stops max.

Its absolutely nuts. With all the housing pricing problems we have in the US its crazy to me that we don't have HSR popping up everywhere to ease restrictions on commute.

Highways are paid for w/taxes. Rail gets no subsidy. Sad really.

Hmm, I hadn't thought of the Chuo Shinkansen as "Maglev in a tube" before...

This makes me wonder, if hyperloop research develops reliable vacuum tubing, whether they could encase the overground sections of the Chuo Shinkansen to make it even faster...

I’d separate:

- longitudinal, predictable acceleration, where you can safely tell people to stay in their seats and all will be fine, I’m quite confident most humans would be comfortable with 1G horizontal that adds up to 1.5G diagonal: that’s basically a roller-coaster; it’s not too bad if you ease people into it, i.e. you minimise the jerk;

- lateral, predictable acceleration, like one would expect in turns: not familiar with train technology enough to know if you could adapt pendular train to MagLev, but it seems like a simple enough hack to increase comfort significantly;

- vibrations and turbulences: seem unlikely in a tube on rails, without a train coming in the opposite direction. Those definitely, customers don’t like.

Lateral acceleration is much more annoying to deal with than longitudinal or vertical, even if it's constant. Perhaps they could tilt in bends to convert some of that lateral to vertical?

Banked corners are a thing. The problem is that when you have delays and vehicles operating at low speeds the track is still banked

Hence tilting - high speed vehicles tilt, low speed vehicles don't, and everything works out ok.

Yes, and with no windows, there's zero correlation between acceleration and visual cues. That's a perfect recipe for motion sickness.

Our local trains have cars that can lean a bit on their own. Bank the track a bit, lean the car as needed, the humans on board don't recognize a turn unless they're watching intently out the window.

Turn radius is mostly a cost question. If you want to get from city A to city B the most direct path has zero turns. It's also got stuff you want to avoid to save money.

The viability of Hyperloop One should not be the focus in the context of this article. That's not what this is about at all.

It's that Hyperloop One needed Richard Branson on board because Elon Musk is creating his own competitor now. This is an incredibly smart move to ensure the survivability of the business from a publicity perspective.

Branson has a history of doing things that people thought impossible or just a bad decision (like creating an airline company). Public perception is the name of the game at this stage, not just feasibility. From that perspective, Hyperloop One has effectively done one of the only strategic moves remaining at this point that ensures it has any chance of persuading a government to select them as a preferred vendor (or continue doing so).

Branson's missing a d from his almost nominatively-determining name — the guy's got a talent for self publicity over challenging the incumbency, which for the most part he hasn't since launching Virgin Airlines and Megastores, which were both back in the 80s.

"Branson's missing a d from his almost nominatively-determining name"

Wat?

Edit: This has been a fun puzzle. I read the Wikipedia article for "Nominative determinism" and I've been swapping the letter "d" into various positions of his first and last name trying to figure it out. No luck yet!

I also was confused, but they probably mean “Brandson”

Yes, there we go. I'm genuinely surprised it was anything other than fairly obvious. Perhaps his reputation's different away from the UK?

Seems more like a brand-father, though.

I was thinking "Richard" - "d" = "Richar" or "richer"

Downvotes? Presumably not from Britons or anyone who knows anything about the guys history?

So what HAS he done then, other than brand anything he can then offload to third and fourth parties to run the businesses for him?

And don't say Virgin Galactic - that's just some clever peripheral branding to encourage the likes of the downvoters here that he is in any way novel or dynamic.

He's marketing clever, not strategically or developmentally-so.

Well, you're criticizing him for only acquiring things and slapping his brand on them. But the criticism is leveled in the context of him investing in an unproven technology. It seems like your comment would be more apt if he were taking an action that follows the pattern you are criticizing. For example, if he were acquiring a computer company and calling it Virgin Computing or something.

That's fair enough, I suppose. I guess I simply distrust his motivations beyond self-aggrandizement and inflating the idea that he's somehow an ideas man, when I can't for the life of me think of anything novel he's done for literally decades.

I'm coming across like a 'crab in a bucket' here - I've nothing against the guy or his success, but I'm not for one second convinced he's 'challenging the impossible'.

He's worth $5 billion. He's a high-school drop-out dyslexic that started from nothing. He built a successful airline and record label, along with countless successful branded companies whose success partially rides on the vast effort he has put into building his own well-known brand - a substantial feat unto itself.

Yes, golly gee, what HAS he done.

While what he has done should be commended, I don't think it's fair to say that he "started from nothing". His own mother was an entrepreneur, obviously not as successful as him but come on, he went to a "prep school" for goodness sake[1].

1 - https://en.wikipedia.org/wiki/Richard_Branson#Early_life

The point is that he built his businesses from scratch, and did so with a significant learning disability that meant he struggled to understand even basic P&L statements and balance sheets. His mother didn't build his record store or record label. His mother didn't build his airline. His mother didn't build his brand.

His early business successes were built from nothing. They weren't seeded with millions of dollars. They weren't inherited. He rolled one success into another.

This obnoxious notion, so common on HN, that someone has to crawl out of a ditch with not a penny to their name, or they're not self-made or deserving of any credit for their own success, needs to stop. It eliminates nearly every possible success story that could exist (which is of course the whole point). It's nothing more than a base envious desire to drag someone down because they've been successful.

On the other end is the absurd notion that someone who starts with a (comparatively) huge cushion or even more is "self-made" in any meaningful sense of the term.

Take this example: Bill Gates as compared with Jan Koum. Applying the label "self-made" to both of them is nonsense. There's nothing "envious" in pointing out that one had a lot more going for him than the other.

I trust my respone to 'waegawegawe' pads out where I'm coming from.

He has a certain reputation here in Britain, however we here in Britain also have a certain reputation of shitting on people's success - I sincerely hope that's not how I'm coming across here.

Anyway, this is tangential nonsense, I'm sorry for diluting discourse!

> however we here in Britain also have a certain reputation of shitting on people's success

That's okay, I appreciate you loaning us John Oliver. ;)

In a sense, I think you gave him to us. You often do :)

I don't know much about that, but ever since the 'Traingate'[1] spectacle I've lost all respect for Branson.

1 - https://www.youtube.com/watch?v=47fqjA8CwGE

For me the sheen came off his lustre a bit back when I was trading at festivals, and at his 'V' festival the only cola drink that was allowed to be sold on-site was the God-awful 'Virgin Cola'.

Minded me of the sort of criticisms he'd level at the likes of BA back in days of yore...

There was never any lustre for me, the first thing I ever knew about "Virgin" was "virgin mobil, which was "free" if you'd click through ads. It was aimed at youth who didn't have much pocket money and I thought that was just awful that teens were clicking through ads to answer the phone.

he hasn't since launching Virgin Airlines and Megastores, which were both back in the 80s.

There's a jar of Branson Pickle in every home in England!

But his moves into healthcare are looking extremely dodgy and of course he lives offshore in a tax haven.

> There's a jar of Branson Pickle in every home in England!

Is this humour? The pickle, and beans, are Branston.

https://en.wikipedia.org/wiki/Branston_(brand)

> But his moves into healthcare are looking extremely dodgy

His healthcare stuff is really dodgy. There are already serious concerns about care and treatment at his places.

The viability of hyperloop is nil. It doesn't exist. It is literally physically impossible for it to be viable.

I think it's on-topic whenever hyperloop is on-topic.

Okay, great. It's on topic. So what?

Why is hyperloop's viability nil and nonexistent?

That's been well covered elsewhere in this thread and other threads.

I'm not going to say the claim it's not viable is original, nor am I going to argue that claim. But it is on topic.

Physically impossible or economically impossible? The physics doesn't look impossible at first glance.

Branson owns both an airline and a high-speed rail service. He seems like an eminently sensible choice of partner for Hyperloop. The institutional expertise that Virgin Group are bringing to the table will be at least as important as the capital investment.

> Branson owns both an airline and a high-speed rail service.

I can't speak to the airline but the rail service is universally reknowned in the UK as "piss poor", especially since they get huge government subsidies.

Both Virgin Trains (51% Virgin Group) and Virgin Trains East Coast (10% Virgin Group) pay large net premiums to the government (£153 million and £204 million respectively).

The huge government subsidies go to Network Rail, a company wholly owned by HM Government, and are never seen by any of the train operating companies (except insofar as they are indirectly subsidised given they don't pay the full cost of maintaining and improving the infrastructure).

https://www.tuc.org.uk/news/private-rail-operators-using-pub...

Has a total net of -£225M from Virgin in 2013/4.

This shows them as still being net-subsidised: http://orr.gov.uk/__data/assets/pdf_file/0008/25757/rail-fin...

Both of those are including the Network Grant; note the ORR document gives Virgin Trains East Coast as paying a net premium in 2016–7 (which I hadn't been able to find figures for before) even including the Network Grant.

Note that apportioning the Network Grant based on percentage of track access charges isn't entirely fair: Virgin Trains notably pays above average per km as a result of funding agreements for the WCML Modernisation programme in the 90s/00s, and as such given the different funding agreements for different network improvements (with the shortfall mostly coming from the Network Grant since the demise of Railtrack plc) it doesn't really make sense to apportion the Network Grant in that way.

> Both of those are including the Network Grant

The result is that Virgin (as a whole) gets more from UKGOV than it sends back as shown in UKGOV's own figures.

> isn't entirely fair

You want to argue with UKGOV and their own numbers, go ahead, but it doesn't change what they currently are.

The problem is it's a separate organization spending the money. So, while you can point to cost aka actual spending it's unclear what the net benefit from that spending is.

Are you kidding? The Virgin carriages are insanely nicer than all the other ones; they feel like airline cabins, while other carriages feel like buses.

Having used Virgin West Coast many times since they took over, sure, they are better than some. When they're not reeking of urine because the toilets have leaked -again-. Or when the aircon isn't broken. Or when the heating isn't broken. Or when the toilets actually work. Or when you can actually use a carriage because they aren't 200% overbooked due to Virgin's utterly insane customer hostile "peak" restrictions and the ridiculous waste of space by empty first class carriages.

Something I wrote a while ago.... w/ back of the napkin calculations.......

Why I wouldn’t invest a money into Hyperloop

- Stabilizing a single fault line risk pylon is more than $250K.

- How many million are needed for vacuum pumps to evacuate 100+ million cubic feet of of pipe to 100 Pa?

- Hot air discharge needs to go somewhere. For every 1 bar pressure, you need ~200 to ~400 cubic meters of volume which is larger

- This seems very much like one of those Andy Grove Fallacies.

- The hyperloop is a mega engineering project on the ground. Nobody on their team is a civil engineer. Looking at their team objectively, there seems to be a mismatch of competency.

- At its core, the science i good, the cost-economics do not work. Das ist nicht gute.

When Musk first said that an LA<->SF Hyperloop could be built for 1/8th the cost of the equivalent HSR, I chuckled and then waited for the punchline, which still hasn’t arrived.

It’s a cool idea and I do want to see more prototypes and feasibility studies, but people need to get off the hype train (no pun intended) and be realistic about the cost.

> When Musk first said that an LA<->SF Hyperloop could be built for 1/8th the cost of the equivalent HSR, I chuckled and then waited for the punchline, which still hasn’t arrived.

Yeah, and that proposal was for something with much lower throughput, that didn't have stops along the way, and didn't even reach the same areas (they saved money by stopping outside both cities, which the rail line wouldn't do). It also assumed that the tubes could just be placed along the highway meridians (a lot of the money it was supposed to save was from this).

To be fair, if Elon worked in the project for 40 - 80 hours a week, he probably could get a team to accomplish it at 1/8th the cost or lower.

Consider he did this with rockets, getting them to under 1/10th the cost

He hasn’t done that with rockets. He wants to eventually, but he hasn’t yet. Let’s not let hype cloud facts.

He's getting very close, if one is considering domestic rockets. The standard-bearers were the Delta IV and Atlas V, which price out at around $17,000/kg - $20,000/kg to LEO, respectively. The Falcon 9 comes in at about $2,800/kg to LEO.

Comparisons with non-domestic rockets are complicated by state subsidies and differentials in labor costs. But the Falcon 9 is approaching the 10X mark even before reusability has been priced in. Both the Falcon Heavy (in a few months) and the (eventual) reusable pricing should overshoot the 10X mark substantially.

Where are you pulling those numbers from? On ULA's website [1] they say you can launch an Atlas V for less than half the $/kg you listed

[1] I went to rocketbuilder.com and both LEO configurations I tried were around $8,000/kg (and I didn't count the 20% deduction for "ULA added value" since the numbers there are debatable)

ULA has abruptly gotten way more competitive in their pricing. A few years ago they were not. Their "Best deal" for the Atlas V was a 36-rocket "bulk buy" priced the lowest-tier Atlas V 401 at $164M/launch[1]. That does 9,797kg to LEO[2], or $16,740/kg.

The GAO cites $164M/launch as the price for the cheapest Delta V[3] (is there some kind of threshold at $165M?), which when the Falcon 9 was introduced could put 8,500kg to LEO[4], or $19,294/kg. (It has since been uprated and gotten slightly cheaper).

Must've screwed up my calculations earlier, because those aren't tallying. Anyhow, as you can see, SpaceX is already around 7x cheaper compared to where ULA was, and should cross the 10x threshold shortly. Nice to see ULA responding to competitive pressure, however!

1: https://web.archive.org/web/20160324172526/http://www.ulalau...

2: https://en.wikipedia.org/wiki/Atlas_V

3: http://www.gao.gov/products/GAO-17-609

4: https://en.wikipedia.org/wiki/Delta_IV#Delta_IV_Small

For the "block buy", that price includes building the rocket but not the launch.

With rockets he was competing with fat and lazy government contractors for the most part. The hyperloop will be competing with already cutthroat airlines, the goddamn personal automobile, and, ...well, a fat and lazy passenger train company.

IMHO he'll be well over 1/10 the cost before he finishes the thousands of land deals he would need for this, even if he somehow got permission to build it over the highway.

> even if he somehow got permission to build it over the highway.

Hence the boring company.

Which won't do anything, because you can't magically make tunnelling cheap

You can't do it magically, but you can do it by improving the technology - see for example SpaceX.

SpaceX is cheap due to reuse and commercial of the shelf development compared to mostly military-government development.

Tunneling gets cheaper due to <...>? I would be interested.

I guess the Swiss would be interested too.

Musk talked about it here: https://medium.com/@giftedproducts/elon-musks-ted-talk-2017-...

Salient points:

"If you just do two things you can get to approximately an order of magnitude improvement, and then go beyond that. The first thing to do is cut the tunnel diameter by 2 times or more. A single road tunnel has to be 26 to 28 feet in diameter to allow for crashes and emergency vehicles and sufficient ventilation for combustion engine cars.

But if you shrunk it to 12 feet, what we're attempting, which is plenty for a skate to get through, you drop the diameter by a factor of two and the cross-sectional area by a factor of 4. The tunnel costs scales with the cross-sectional area. That's roughly half an order of magnitude improvement right there.

Then, tunneling machines tunnel half time and then stop and the rest of the time is reinforcements for the tunnel walls. If you design the machine to do continuous tunneling and reinforcing, that will give you a factor of two improvement. Combine that, and it's a factor of 8. Also these machines are far from being at their power or thermal limit. I think you can get a factor of two, maybe even four or five on top of that.

There’s a fairly straightforward series of steps to get somewhere in excess of an order of magnitude improvement in cost per mile. Our target actually is that we have pet snail named Gary from....Sponge Bob Square Pants. Gary is capable of going 14 times faster than a tunnel boring machine. We want to beat Gary."

Is this not an attempt to just derail CAHSR, or HSR in general? Nearly every anti-HSR comment is now 'we should build hyperloop instead!'.

That's impressively cynical, but Musk obviously stands to gain a lot if people keep California using roads. California wants to go green and he sells the best technology for green road-based transportation.

To be fair, he also stands a lot to gain if Hyperloop becomes a reality.

How does that work? He had an idea and promoted it. No one's going to be paying him royalties for it.

He's also building one, so he has a vested interest in the technology being successful: https://techcrunch.com/2017/08/04/elon-musk-reportedly-plann...

heh.

Reminds me of when an actual AI expert pointed out that by making dire predictions about smart AI, that we are nowhere near having, keeps eyes off the autopilot system and the issues with that.

I'm not sure it really affects his electronic car business one way or the other. Firstly, he isn't necessarily selling Tesla's to people for commuting between SF and LA, that's well outside his range, and as fast as the supercharging is, it loses out to regular gasoline refilling. Secondly, I'm not sure the amount of people potentially served by the hyperloop is more than a blip in the sales charts for even a regular car company (as deciding factors for car purchasing decisions, it seems relatively low to me).

Okay, we'll bookmark this for the future. Amtrak estimated a HSR/"bullet train" from D.C. to Boston would cost ~$151 billion. Since LA to SF will only be two stops, and we can assume Amtrak estimated at least 4 (Philly and NYC) let's bring the number down closer to $100 billion to make it even.

Do we think the Hyperloop costs are more or less than that? 1/8 of a theoretical $100b is $12.5b -- is $12.5billion for Hyperloop unreasonable? I have no opinion on cost personally, and I don't know economics, but this $151 billion from D.C. to Boston was floated by the established US player in rail infrastructure. Anything less than that number is fantastic, right?

You cannot compare D.C to Boston with SF to LAX. The east coast has much denser population so that you need more tunnels. LAX to SF HSR would not cost $151bn. Start and end are expensive but the part in the middle is "relatively" cheap.

Right, for comparison's sake I chopped off $51 billion bucks from the Northeast Corridor projection in the interest of balancing out the two.

Just because I felt like doing some more Google-fu, I found an article in the LA Times[0] that says a California HSR/bullet-train project is going to overshoot it's original budget (and deadline) of $68 billion. There's a lot of info out there about this project, and it's potential overruns, but let's forget all that and just stick to the original planned cost: $68 billion, so, about half of the cost of Amtrak's northeastern bullet. Let's use that number for our comparison.

If we are going to hold Elon to his "we can do it for 1/8th the cost" blurb, then we are giving him like $8.5 billion to use for his SF/LA Hyperloop. Still, that doesn't sound unreasonable, right? He'll get a good deal on tunnel boring with his other company, and fuselage manufacturing can be handled by SpaceX. When it comes to financing, I don't think it's a major issue compared to other infrastructure works out there.

Like I said, though, I'm just going off the top of my head. I don't know finance or economics or vacuums or magnets.

There's a new LIRR train being dug in NYC called East Side Access. This is a commuter rail line, and is going to cost ~$10 billion or so[1]. Logistically these aren't the same, obviously, but if adding to the LIRR is worth ~$10b then surely the Hyperloop experiment is as well, right?

EDIT: Also, just for disclosure, I don't live in California and I'd probably never end up using the Hyperloop myself so I'm neither for nor against it versus any HSR. I just want to entertain the idea that cost shouldn't be the main focus of discussion IMO.

___

0. http://www.latimes.com/local/california/la-me-bullet-train-c... 1. http://web.mta.info/capital/esa_alt.html

> If we are going to hold Elon to his "we can do it for 1/8th the cost" blurb, then we are giving him like $8.5 billion to use for his SF/LA Hyperloop. Still, that doesn't sound unreasonable, right

I think boring company claimed it can bring down costs to 100 million dollars per mile (how? Just reduce tunnel size! SMH. Plus 100 million dollar a mile isn't too far from prices of current tunnels). Sf to la is 380 miles. That's 38 billion dollars just for the tunnel?

I think hyperloop is certainly feasible, if you spend hundreds of billions in it, the problems can be dealt with costly engineering.

If you think hsr will cost 150 billion, a maglev will be costlier, tunnels are extremely costly to build, but building a maglev in a vacuum tunnel will cost only 6 billion? How will cost savings of an order of magnitude happen?

> Okay, we'll bookmark this for the future. Amtrak estimated a HSR/"bullet train" from D.C. to Boston would cost ~$151 billion. Since LA to SF will only be two stops, and we can assume Amtrak estimated at least 4 (Philly and NYC) let's bring the number down closer to $100 billion to make it even.

You're starting with the wrong number. The $151B number is Amtrak's estimated cost for it's "shoot for the stars" plan. Its basic NEC stretch plan is effectively 4-track corridor (shared with commuter rail) from DC to Boston, with new stations and new inner city track being laid in Philly and Baltimore, two new Hudson River tubes and a new station annex in NYC, among other less notable improvements. I don't recall if the "abandon current Connecticut track and instead go from NYC along Long Island and tunnel under the sound" plan is in that tier or the next one. The stretch tier is somewhere in the region of $70B.

The reach for the stars tier is "do all that, and then build a parallel 2-track dedicated HSR track from DC to Boston." That's $150B. Which means building dedicated track from DC to Boston is only $80B. The estimated full buildout for CAHSR (including San Diego and Sacremento) is around $80B, as I recall.

Meanwhile Switzerland, one of the top most expensive countries in the world, has tunnelled at the base below the alps (one of the most difficult terrains to tunnel due to vertical sediment layers) for ~20B. Workers died on that project too, but that risk is simply being managed rather than grinding everything to a halt.

I'd argue it's absolutely possible to improve the cost on American public transit infrastructure by one to two orders of magnitude if you can simply get a way around government capture.

How much was there in land take for the Gotthard Base Tunnel? How much land take would there be for Amtrak's $80B line from DC to Boston?

My guess would be that the cost of land in the north-east, combined with AFAIK pretty strong ownership rights, makes it that expensive.

While American construction costs do seem to run higher than comparative costs in Europe and Asia, the multiplier is closer to something around 2-3×, not 10-100×.

The cost of the Gotthard Base Tunnel comes out to around $300-400 million / km. By comparison, the Second Avenue Subway comes out to around $800-1000 million / km (I'm subtracting a bit because the subway has three stops--which tend to be really expensive money pits--and the base tunnel does not).

Honestly, 12.5B look like a ridiculously small amount to me for an infrastructure project stretching along 550Km and involving an unproven, technically very challenging technology.

I'm not saying the hyperloop is a good or bad idea, but any suggestion that it would be cheaper than the equivalent HSR seems utterly insane. How could it possibly be cheaper? You have the same ROW requirements, exponentially more expensive track, and the overhead of the fact that it's brand new technology. The fact that the vehicle itself might be cheaper than an HSR train after the tech scales up is almost an afterthought next to those costs.

The track should be cheaper because hyperloop has (almost) no impact on existing infrastructures. Expropriation costs for train are huge.

How could the Hyperloop not require the same expropriations? A giant tube isn't any smaller than a train track. Is it the fact that it's elevated? Rail can be elevated. Yes, rail is heavy, but so are giant evacuated steel tubes.

Run it down the center of the freeway? Having stations for trains in the middle of freeways isn't great for pedestrians, but might be fine for long distance transport such as hyperloop.

HSR is supposed to be log distance transport. It's I meant to solve the exact same problems as Hyperloop, but by powerful engines and streamlined railcars instead of evacuated tubes.

Again, why not put HSR tracks in the same place you'd put a Hyperloop track? Put the station in the same place. The tubes aren't smaller or lighter.

I think he's planning on making lots of tunnels.

https://www.wired.com/story/elon-musk-test-tunnel/

Tunnels are very, very expensive.

e.g. https://pedestrianobservations.com/2016/12/15/second-avenue-...

> The total length of the project, from 96th Street and 2nd Avenue to 125th Street and Lexington, is about 2.7 km. At $2.2 billion per km, this sets a new world record for subway construction costs, breaking that of the first phase of the same line, which only cost $1.7 billion per km.

I read one article that blamed the high cost of modern subways primarily on the hyper-elaborate modern subway stations and the actual tunnels are a small component of the cost.

I think you're right - tunnels seem to be about $200-400M per km when considered purely on their own.

Musk seems to think he can do it faster/cheaper. His track record makes it worth considering.

The article I linked to smacks his arrogance down over costs that he's overlooking, but even that may be addressable. Let's see what he delivers in the next 5 years.

I don't think Musk want hyperloop to be built above the ground. This is just my own personal opinion, not sure if that's how it's going to work, but in one of his interview (TED? I think), he mentioned one of the reasons for his Boring company, was it would be relatively cheaper to build hyperloop - because the atmospheric pressure will be lower underground - and since you don't have to worry about building large infrastructure for only one purpose (hyperloop) - the cost will be much much cheaper. Because under ground tunnels can be build for both hyperloop and roads for cars and it scale better than above ground.

I don't think above ground is economically and technically feasible, there are just too many unanswered issue that almost no one has answer to. Not to mention it will be very very expensive and time consuming.

Why would atmospheric pressure be lower underground?

Tunnel boring is orders of magnitude more expensive than railway construction, at typically ~a few hundred million dollars per mile vs ~a few million dollars per mile. I know Musk has plans to magically make tunnel boring significantly cheaper but you need two orders of magnitude cost reduction to make the tunnel digging not cost more than an entire above ground railway.

Cost references: https://tunneltalk.com/TunnelTECH-Apr2015-Arup-large-diamete...

https://www.compassinternational.net/railroad-engineering-co...

Maybe you're looking in the wrong place for the punchline. Perhaps it will be delivered in the final bill for the HSR...

Everyone has been chuckling about electric cars and private rockets until recently, and that was by experts in the respective fields. Chuckle all you want.

Go here and scroll down to "Select historical production vehicles" - https://en.wikipedia.org/wiki/History_of_the_electric_vehicl...

I grew up in the 70s and saw production electric vehicles that are not on this list. People have been chuckling for a long time and for good reason. It's not that electric vehicles won't eventually be successful -- they must. It's that the time from, "Hey, an electric vehicle would be a good idea" to "Hey, we've figured out all the engineering challenges to make this viable" is longer than the lifetime of most of the companies that entered the fray.

Look at the list of vehicles from before 1990. That's the "getting to the market first" list. All gone. Then look at the list from 1990 to 2010. How many of those will be major players in the electric vehicle market? My point is that I'm relatively old for someone on HN and there have been production electric vehicles since well before I was born. They only started to be viable in the last few years -- and even then, we probably need a few more breakthroughs in battery technology before the market settles out.

Long distance, super fast trains in tunnels? https://en.wikipedia.org/wiki/Ch%C5%AB%C5%8D_Shinkansen I saw the tunnel the other day. I was surprised that practically the whole damn length of the maglev tracks will be in a tunnel, but it makes total sense. That's been under construction for 10 years. They are optimistically expecting to make a profit in 2026 when "costs stabilise".

Will long distance, high speed trains in low pressure tunnels be successful? I have no doubt. Will Hyperloop One be successful? Umm... frozen balls of ice remaining intact in a very hot place probably have a better chance, but I won't say they will definitely fail. If they can secure something like a trillion dollars and invest it wisely over the next 30-40 years, then their chances will improve significantly.

Let me be clear. I was talking about criticism of Musk specifically. Pretty much EVERYONE in the aerospace industry thought he was nuts, and yet SpaceX made it to orbit. Even a couple months before their first stage landing others were saying it was impossible.

Assuming your are correct and Branson knows it because he hired good engineering advisers. Why would Branson get involved ?

- It is a cool project he wants to be part of and he is willing to pay to see. (I would probably do that)

- The benefit is not to reach the goal but all the technology that will be invented trying to reach the goal.

> Why would Branson get involved ?

Branson is notorious for burning other peoples’ money. Look at Virgin Galactic: it’s New Mexicans’ [1] and Floridians’ [2] tax money plus some duped Emiratis [3]. (They also pre-sold tickets [4].)

[1] https://www.theguardian.com/us-news/2015/oct/04/space-travel...

[2] http://www.airnewstimes.co.uk/space-florida-promises-virgin-...

[3] https://dealbook.nytimes.com/2009/07/28/uaes-aabar-takes-sta...

[4] https://www.smithsonianmag.com/smart-news/

Branson's business model is selling the right to use the Virgin brand to other companies. The article doesn't say he made an investment. It is rather more likely that they paid him.

So basically Trump with more class?

...and fewer bankruptcies.

Although if you believe Private Eye about the state of Virgin's finances (convoluted, shifty, and blistering opaque), this may or may not be true.

Is that actually the case? My impression is that the vast majority of companies bearing the Virgin brand was either started by Virgin Group, bought by them, or has seen a significant investment. Many have since been divested again, and continued to license the brand, but I've not heard about any cases where they just licensed the brand without other financial involvement. Maybe I've just not paid attention?

https://en.wikipedia.org/wiki/Virgin_Group#Subsidiaries_and_... shows the majority being 100% owned by the Virgin Group, though notably none of the airlines nor rail operators are.

> The article doesn't say he made an investment.

Actually, from the article:

> Hyperloop One has received a significant investment in Hyperloop One

And from the page linked to in that paragraph:

> Delighted to announce Virgin Group’s investment in Hyperloop One

Not exactly ambiguous.

People often, rightfully so, confuse the misappropriated name of Hyperloop One with Elon's Hyperloop idea, his of which I believe does have sound economics and certainly its pro list outweighs Hyperloop One's technology.

Could you point out the differences in both technological and economical approaches?

I'll try to remember to reply to this after the weekend, if not and you're still interested shoot me an email matt@engn.com

I don't think it's right to use figures that can change to disprove an Elon Musk concept. If you did that back in the day, you would say there's no way Tesla could work because the cost of batteries is prohibitive and the supply too limited.

This is the real insight.

Yes, but we could see that batteries needed to get X better in order for us to achieve Y results in the future. But how much better do vacuum chamber technologies have to get before you can make the biggest one ever built, that also has a high-speed capsule traveling through it, that is also impervious to armor piercing bullets? Furthermore, imagine if every airplane had to fly the exactly same path, and if any failure on that path prevented (at the very least) all subsequent planes from traveling that path. And finally, how are security lines going to get shorter if the stakes will be at least as high as airplanes?

I don't know the answers to these questions, but what I do know is:

1. Elon Musk has thought about them more than we have.

2. If his initial concept turns out to be incorrect in some way, he will change it until it is workable.

Are airliners impervious to armor piercing bullets? As I understand it, a small bullet penetrating the loop will cause a minor release, not a catastrophic event. It's not correct to hold the Hyperloop idea to standards that we don't apply to other forms of travel.

There's a very pertinent historical reference point: Ferdinand de Lesseps. He built the Suez Canal from 1859 to 1869, a task which was considered by many to be impossible or at least impracticable [1]. After achieving resounding success, he then turned to Panama to try building the Panama Canal. In this venture, he turned out to have several very wrong ideas (it's not feasible to build a sea-level canal in Panama), and the French effort failed so hard it actually brought down the French government [2]. He was successful in the first venture but for different reasons than initially assumed (namely, the Suez Canal isn't all that challenging from an engineering perspective; it's just capital-intensive), and his failure in the second venture comes from misunderstanding the problems.

[1] There had been canals in the past that traveled from the Red Sea to the Nile delta, but these invariably silted up rather quickly (the Nile was sediment-heavy, and wind-blown sand is quite common in the region). Thus there was historical evidence favoring the idea that the dredging maintenance fees would exceed the revenue from passing ships.

[2] Of course, this was the Third Republic, which is notorious for having provided series of weak, unstable governments replete with scandals that prompt new governments. Ironically, the Third Republic was the longest-lasting form of government France has had since the Ancien Régime.

To this day, the Third Republic is still the longest lasting.

> Das ist nicht gute.

Should be "Das ist nicht gut".

An initial pipeline could be built with a lower target speed. This would postpone some of the potential challenges with regard to heat dissipation, and also route selection.

For example, you wouldn't have to worry so much about tunneling under a mountain to ameliorate the G-forces if you are traveling more slowly. Once you prove out the route (which could still be competitive with any existing train service), you incrementally build tunnels and modify the route to improve your target speed.

(As for heat discharge, Im pretty sure that was addressed in EM's original paper - dumping the excess heat into an on-board water tank which is exchanged at the end of the ride, or are you referring to something else?)

All of the Hyperloop development efforts are ignoring the elephant in the room: thermal expansion. If you do the math, the ends of a viable hyperloop track will have to move hundreds of meters [1]. No one has yet advanced even a viable idea for how to deal with that, let alone an actual design. Until that happens, the Hyperloop is vaporware.

[1] It's a trivial calculation. The thermal expansion coefficient of steel is about 10^-5. A typical run of, say, SF->LA is 600 km. Temperatures in the central valley range over about 100 degrees. Multiply everything together and the result is 600 meters.

Expansion joints are available since decades.

Not ones that will hold a vacuum.

I am not an engineer. Is it impossible to create one? If a tube is a vacuum, then the tube moves, I don't think that negates the vacuum or does expansion and contraction make a vacuum impossible? I wouldn't believe so.

Impossible not. But expensive. And hyperloop is supposed to be cheaper than HSR.

Not with that attitude.

Your comment may seem flippant, but honestly it seems like people are more eager to be right than aspirational these days.

It's not about being right, it's about pure attitude - "why this can't work" vs. "let's talk how can we make this work".

I don't think people are actually that defeatist. If it came to a difficult situation in their own lives, I bet they'd rise to the occasion, but they'd rather see others fail than succeed greater than they did.

Did you try googling? Here's a whole bunch: http://www.metraflex.com/metal-expansion-joints/

Let me be more precise: not ones that 1) will hold a vacuum and 2) are available in the 3+ meter diameter that the hyperloop requires and 3) provides the smooth inside surface that the hyperloop requires and 4) are economically viable.

This kind of Hyperloop criticism is commonplace, but strikes me as intellectually lazy. Did you read Robotbeat's link? Particularly with respect to to the MNLC Bellows Expansion Joint.

> 1) will hold a vacuum

Plain wrong.

> 2) are available in the 3+ meter diameter that the hyperloop requires

This is a simple manufacturing problem, although calling a "problem" seems like an overstatement. Obviously not everything to build a Hyperloop is wholly off the shelf. If there is some reason why this can't be built in larger diameters, then that's certainly not obvious.

> 3) provides the smooth inside surface that the hyperloop requires

The Hyperloop runs on an air cushion. It's a hovercraft. Millimeter-scale bellows ought not to be a problem.

> 4) are economically viable

And here, you could be entirely correct, and is why I'm not yet a Hyperloop true believer. I'm not wholly convinced that this kind of machinery can be economical over its whole life-cycle in its intended service environment. But proving that this is the case requires more than glib, hand-wavy assumptions. You need to run the numbers. I have yet to see any Hyperloop critic do that in a remotely convincing fashion, whereas there are many Hyperloop engineers who most assuredly are running numbers. Maybe those calculations are wrong, but the only way to refute them is with better calculations. Anything else is just dogma.

HyperLoop does NOT run on an air cushion (remember, the entire tube is supposed to be nearly evacuated!), but instead floats on a maglev track.

He's also missing another requirement: 5) The entire track, including any possible expansion components, valves, inspection hatches, etc etc etc have to be at least mildly tolerant to intentional or accidental damage. Running into a sudden wall of air at 700mph is a good way to destroy any passenger craft in the system.

That depends on the design. In Elon's original paper hyperloop the vehicles have an air bearing.

RE 4, there are also two "kinds" of economical viability: the fundamental one, derived straight from physical limits, and the usual "market couldn't be bothered with it" one. Knowing Musk's companies, he cares only about the former, and is willing to push through the latter. Thanks to that, fully electric cars with reasonable range are now not only a possibility, but a desirable product every other car company wants to build too.

The number crunching should tell in which category of viability Hyperloop is.

Just so. In the 1990s I was part of a group called the Space Access Society, which was a bunch of cranky but idealistic rocket scientists (and enthusiastic amateurs; John Carmack was a constant presence with his Armadillo Aerospace) trying to foster cheap access to space by any means possible.

These efforts were regarded with huge levels of skepticism / disinterest / dismissal from NASA and the mainstream aerospace industry, which consistently confused the second kind of viability with the first. When these people couldn't raise and/or manage the funds to actually implement their ideas, this was regarded by many as proof of the physical impossibility of cheap access to space. Most of the industry regarded them as crackpots.

Then Elon Musk came along and proved the crackpots right and the industry wrong. He could do this because physics was on the side of the crackpots and always had been, even if the market was not. That's a necessary but not sufficient condition; what he also needed -- and just barely had -- was the financial resources and organisational capacity to go up against the market and win.

There are aerospace forums[1] where one can still find smatterings of the old guard insisting that Elon Musk is just a smoke-and-mirrors phenomena; that spaceflight will always be intrinsically expensive because physics (in a hand-wavey, strictly no-calculations kind of way) says it must be so; that the only reason his rockets are cheap is because he's underpaying his workforce and working them to death; that it's impossible to re-use a rocket -- seriously, they're still saying this, even after it's been done three times already; that the Shuttle proved that reusability can never lower the cost of spaceflight, etc. etc. etc.

Some of these people have PhDs in aerospace engineering; some of them have worked on the space shuttle. No matter: they're in the throes of a cargo cult, and they're wrong. Physics are right.

Do the numbers. Engineering is done with numbers. Analysis without numbers is only an opinion.[2]

1: forum.nasaspaceflight.com/index.php

2: http://spacecraft.ssl.umd.edu/akins_laws.html

Thank you for posting this. With all kinds of matter-of-fact comments confidently declaring the impossibility of feasible hyperloop implementations, a lot of those arguments turn out to hinge on random, idiosyncratic details that are not at all the dealbreakers they're made out to be.

I am curious, does an expansion joint not help here? Is it impossible to make an expansion joint that deals with the kinds of pressure involved?

Expansion joint is likely the way to do it, but I'm not aware of vacuum expansion joints of that size. Even if it's possible, it sounds very expensive to make and to maintain. Just like everything in this project.

That's the thing about Hyperloop. It's not technologically impossible. It's just not economically viable.

> That's the thing about Hyperloop. It's not technologically impossible. It's just not economically viable.

That's probably why this is an idea from Elon, not from the industry. The guy has a habit of forcing the market itself to accept beneficial ideas, and in the process they become viable.

Just to clarify - is the thermal expansion issue both in terms of the length of the hyperloop and the inside diameter of the tube, or just the length?

Relevant discussion of thermal expansion with high speed tracks: http://boards.straightdope.com/sdmb/showthread.php?t=471152

It's a combination of things: the length, the fact that it has to hold a vacuum, and the fact that it can't make tight curves. If any one of these things weren't true the problem would be easy. But they are all true, and that makes it really, really hard. (Oh, and it has to have a smooth inside surface, and it has to be manufacturable at a reasonable cost.)

Yeah, Elon Musk never thought about that because he was busy landing rockets.

Come on.. why do you think he did not think about that?

By the way, curves in the track can eliminate this when they can slide a little. And I can imagine there are more and better solutions.

Relevant: http://www.commitstrip.com/en/2016/06/02/thank-god-for-comme...

> why do you think he did not think about that?

Because this issue has been brought up many, many times since the Hyperloop paper was first published and no one has yet proposed a viable solution.

> curves in the track can eliminate this when they can slide a little

But you can't curve the track. The track has to be very nearly straight or the G forces become intolerable.

This is the thing: lots of people glibly propose what they think is a solution, but none of them actually work.

Elon has proposed a solution as others also already comented.

And why would large diameters not work?

> Elon has proposed a solution

Really? What is it?

Elon can get things wrong. He already said after he had announced and hyped hyperloop he had to delay the white paper because it turned out his initial idea just didn't work and he had to come up with a new one.

In 2016 he said we would have full level 5 autonomy in self driving cars within two years. That means in all driving conditions a human could handle.

That seems exceedingly unlikely.

https://electrek.co/2017/04/29/elon-musk-tesla-plan-level-5-...

Musk has addressed this:

Similarly, the proposal briefly discusses thermal expansion: as the steel of the tubes heats in the hot California sun, the metal expands. That expansion needs somewhere to go. In high-speed railways, rails are allowed to overlap at the ends, but that’s not possible in the Hyperloop, and so Musk has a different solution:

“Specially designed slip joints at stations will be able to take any tube length variance due to thermal expansion,” he explained. “This is an ideal location for the thermal expansion joints as the speed is much lower nearby the stations. It thus allows the tube to be smooth and welded along the high speed gliding middle section.”

https://www.theguardian.com/technology/2016/may/12/hyperloop...

I think the hand-wringing over expansion is a bit over the top right now. Seems like its a relatively solved problem and one the Hyperloop team is taking seriously. I imagine the cost of engineering and building giant slip joints is just part of the overall cost package and probably a non-trivial part. I find it hard to believe someone as relatively trustworthy and technical as Musk is selling this concept knowing full well its impossible.

Most likely, this is a solvable problem the same way many difficult problems were solved for cars, planes, and rails during their inception. I read an analysis somewhere that the Wright brothers solved 4 or 5 'hard' problems with their first plane. Their competitors at the time weren't able to solve even one. I'm not saying Hyperloop is guaranteed to work, but declaring it 100% impossible seems overly pessimistic.

My worry is a bit more prosaic, if we gain progressive leadership in congress, we may be looking at Euro-style high speed rail in many US regions, which would invalidate the hyperloop concept. This seems less likely, imo, but by far the saner move.

Does he not realize that you can't just take up all the slack at the ends? That would mean the pylons nearest the station would be pushed over around 300 feet. How would the hyperloop stay elevated without pylons?

Why would the pylons need to move? You can essentially have tube sitting on top of the pylons (which I expect could have ~50 degrees of contact area). You could even have it sitting on rollers between the pylons and the tube.

Is there any material available with a negative expansion coefficient that can be used to offset this?

I ask because that’s how you tend to work around thermal effects in electronics.

An electronic device contains many orders of magnitude less material than a hyperloop track. There are all kinds of materials that are economically viable when measured in micrograms. Hyperloop track material has to be bought by the kiloton.

Compressable joints between each section?

We could replace steel with a low coefficient metal matrix composite without sacrificing stiffness or long range strength. It would blow out the cost structure however ;)

Have also heard anecdotally that condensation in the tube could be a real problem. Even at near vacuum, the rapid pressure differentials can cause buildups in front of and behind the speeding vessel.

> It would blow out the cost structure however

Sure, all of these problems are solvable if you are willing to expend arbitrary resources. But the whole point of this exercise is to provide an economically viable mode of transportation. (Isn't it?)

This point is clearly addressed in the paper: The ends of the tube can slide 300 meters next to the station, and the tube is not firmly attached to the pylons but can move to accommodate the expansion.

No. The paper gets this badly wrong. It looks only at the incremental thermal expansion between pylons, and neglects the fact that in a sealed tube the thermal expansion will be cumulative.

"These would absorb the small length changes between pylons due to thermal changes, as well as long form subtle height changes." [emphasis added]

The cumulative expansion is dealt with in a single sentence:

"A telescoping tube, similar to the boxy ones used to access airplanes at airports would be needed at the end stations to address the cumulative length change of the tube."

But that's not enough. The entire track near the ends is moving by this amount. That means that the ends of the track are advancing and retreating over multiple pylons (unless you can figure out a way to cantilever the track over 300 meters). This is a completely unsolved problem.

sealed telescoping tube between pylons then?

That sounds really expensive.

At this pressure you can use regular o-rings, which already come in standard sizes up to a dozen meters across. They're very affordable. I still doubt they'll be necessary.

I'm not this kind of engineer, but couldn't the pylon problem be addressed by a sliding rail mechanism between the pylon and the sealed tube? Or replicating the station mechanism at each pylon? Maybe I just don't see the problem you're pointing out.

edit: in retrospect, I can clearly see the problem with expanding shaped tracks.

What happens to a long S-shaped track? Think about expanding each segment of the top curve... the turn radius increases and as does the length of the turn. How do you support a tube that can get longer, move outwards along the curve, and change angles at various points? S is just an example, it seems to be a problem with any number of turns (including 1)...

I suppose one option is to simply put it underground to stabilize ambient heat input, and use heat extractors to manage heat generated by the train. If the system shuts down, there might be some thermal contraction but that's easier to manage (it's OK for track segments to separate when trains aren't running - just warm them up before operation)

Maybe move the S shape from the horizontal to the vertical plane. Then, you can handle the bend by dynamically changing the height of the pylons.

It's still an issue that at bends of this diameter, the approximation sin(x) = x is pretty accurate, which means it takes 300m of height difference to deal with 300m of thermal expansion. It might be workable to change that to e.g. 100 bumps of 3m.

How about you also copy the sentence that lies just between those two?

"As land slowly settles to a new position over time, the damper neutral position can be adjusted accordingly."

And if that doesn't work, the tube can have some kind of rails or just to roll over wheels on top of the pylons. (my own thoughts as non expert)

Rocket engineers with advanced simulation tools[0] have been working on this for 5 months before releasing the paper. Do you really think they somehow missed this obvious issue?

[0] https://www.youtube.com/watch?v=vYA0f6R5KAI

Edit: Further in the paper it says: "The tube will be supported by pillars which constrain the tube in the vertical direction but allow longitudinal slip for thermal expansion as well as dampened lateral slip to reduce the risk posed by earthquakes."

So pretty much what I've said. The other quoted sentence refers to placement of pylons themselves.

I dont know if this an elephant in the room. I'm guessing engineers have thought about this and just not discussed it publicly. They have some pretty smart guys.

Also to nitpick, from "the ends of a viable hyperloop track will have to move hundreds of meters" - this doesn't have to be true. There can be absorption points along the track. Overlaps. Or maybe they tunnel the entire way where its cooler. Or wrap the tunnel in something cooling and reflective. We dont have train tracks moving hundreds of meters do we? I dont profess to know the solution, but do know there are solutions somewhere.

> There can be absorption points along the track

Sure, but these have to hold a vacuum. No one has figured out a way to do that.

I am assured by those in a position to know that thermal expansion joints which hold a near-vacuum are an entirely solved and essentially trivial problem.

I do have some concerns about whether they're a trivial problem within this context. An engineering solution which works in small numbers for PhDs in a lab isn't necessarily scalable to mass low-cost manufacturing, deployed in the field and irregularly serviced by workers of uncertain provenance. But evidently there is a way to do this, at least.

And, more importantly, can be certified for real world use. Considering the speeds used, scrutiny will be extremely high. Even if you use it for freight at first, the track will be close to settlements and any accident could end up in a disaster. The behaviour of trains on tracks is very well understood (learning from accidents), the behaviour of a vacuum train tube is not.

This is a very fair point. There might be components that are routinely used in non-life-safety-critical applications, but this is no guarantee that they will pass certification scrutiny when they are in the critical path for thousands of lives every day.

I worked on an autonomous vehicle project here in the UK about 10 years ago (the Heathrow Pod). The certification process was absolutely intense. And this was for a system that was capped at 25mph; had we gone any faster than the regulatory burden would have become very significantly more onerous (below 25mph it wasn't necessary to test vehicles and infrastructure to destruction; above 25mph, it is).

In this domain, there's a huge difference between a cool engineering testbed, a private pilot project, and running actual service for the public. If Hyperloop is going to be doomed by anything, failure to appreciate this fact is probably at the top of the list.

Except for the people who invented the accordion and bellows.

I work in a lab with vacuum systems that get heated and cooled and we just have segments of flexible bellows like this:

http://www.pchemlabs.com/subcatagoryb.asp?pid=flexible-bello...

Not sure if the same thing will work at larger scales, but I'm not sure its a fundamental problem.

Wowza, 5" bellow is $450, how cheap could they make 6' one, even in bulk?

Not exactly like that, but yeah, the same sort of idea I'm sure would work.

Gas pipelines hold hundreds of bar of pressure; I don't see how one atmosphere is a problem.

Gas has no problem flowing around corners. Gas pipelines are usually not straight lines. Hyperloop will have to be a straight line, unless you want to kill passengers.

Gas pipelines use Expansion Loops [1] to pick up expansion slack. The problem is that, in order to push people through the tube at 700mph at acceptable G's, you can't put bends like that in the HyperLoop. If you try to send people down a pipeline at 700mph, you would end up with paste at the other side. Gas pipelines are surprisingly un-straight, bendy, and bumpy

[1] https://static.interestingengineering.com/images/import/2017...

Isn't this what a syringe does?

Wouldn't they just put accordion joints on the junction at every pylon? It's not like the tube is going to be built as one gigantic piece. It has to be assembled from parts.

The vacuum is the problem. With HSR you also have small gaps in the system to allow for expansion but nothing there requires a perfect surface.

AFAIK, high speed rails do not have gaps. Expansion is controlled by brute force : lots of clamping and massive supports.

They can have expansion joints around bridges, but generally speaking you're correct, they're thermite-welded and adjusted to correctly handle thermal stresses without kinking (heat expansion) or fracturing (cold contraction).

This is only if the tube sections all move together. This could be handled at the joint between each tube section, and then the joints would only have to move a fraction of that distance.

Many replies mention expansion joints. There are also other techniques that can be used: for example pre-stressing as is done with continuous weld rails:

https://en.wikipedia.org/wiki/Rail_stressing

Overall, it is not a particularly difficult engineering problem.

When are we going to address the elephants in the room?

Just the tube alone:

  - largest pressure vessel in the world. How do you keep it at near vacuum?
  - Thermal expansion over such a large distance, especially if the top of the tube is warmer than the bottom.
  - Safety, how does an evacuation look like if the tubes are sealed?.

There are many more. Some how I feel like this is a "pipe" dream. Lots of marketing, very little engineering.

The pressure tube doesn't need to be at near-vacuum. By the drag equation, air resistance is proportional to pressure; merely cutting pressure by 90% would reduce air resistance by the same amount, and that's trivial with perfectly ordinary pumps.

Serious vacuum pumps are not required. This is not to say that keeping it airtight won't still be a major engineering problem, it just isn't as near-impossible as near-vacuum would be.

To cope with expansion, you'd need to use sliding plates--which, yes, will make it harder to keep the air out. That's going to be an interesting challenge.

Doesn't the Hyperloop concept rely on not having a perfect vacuum? It's supposed to suck in air on the front and blow it out the bottom as an air cushion. Without the air cushion you just have "maglev in a vacuum" instead.

I'm sure that's also a fast mode of travel, but like you said, the vacuum part of it takes a lot of money.

Does the vacuum part take a lot of money? I would think that if anyone knows, it'd be someone like Elon Musk who has built a spacecraft company from the ground up.

For many of Elon Musk's projects, I get the idea that Elon is mostly just bringing broad, multi-domain knowledge to bear on industries that have been siloed for a very long time. So everyone scoffs at a long vacuum tube and using turbomachinery, etc, but for someone with a physics background with extensive knowledge of the spacecraft environment, turbopump rocket engines, and all the subsystems and ground testing systems that enable all this, it really isn't far-fetched at all. Most physicists (of the experimental kind, i.e. those who have to have hands-on knowledge fabricating things in addition to theoretical background) that I've talked to understand his ideas and think they're fairly reasonable.

People seem to base most of their criticisms on the fact that it's different than what we already do without a fundamental, first-principles understanding of the system.

A real vacuum (or very close to it) would be expensive, yes. That's what Musk designed the hyperloop to avoid; it works with a "low pressure" tube instead. His original hyperloop proposal paper outlines this in the intro:

http://www.spacex.com/sites/spacex/files/hyperloop_alpha.pdf

Another extreme is the approach, advocated by Rand and ET3, of drawing a hard or near hard vacuum in the tube and then using an electromagnetic suspension. The problem with this approach is that it is incredibly hard to maintain a near vacuum in a room, let alone 700 miles (round trip) of large tube with dozens of station gateways and thousands of pods entering and exiting every day. All it takes is one leaky seal or a small crack somewhere in the hundreds of miles of tube and the whole system stops working.

However, a low pressure (vs. almost no pressure) system set to a level where standard commercial pumps could easily overcome an air leak and the transport pods could handle variable air density would be inherently robust. Unfortunately, this means that there is a non-trivial amount of air in the tube and leads us straight into another problem.

The "another problem" being that if you just do low pressure, it means your pod has air in front if it and has to pushing that air around (or if that air has nowhere else to go in the forward tubing, trying to compress it, because not enough of the air can squeeze around the pods at the edge of the tube). That's what the hyperloop is getting around by sucking air in the front and blowing it out the bottom. Working as an air cushion is something of a bonus, and if everything works out right it also lets you avoid the expense of maglev.

The CERN LHC tube is a 27km circle of vacuum and near-zero temperature, and they don't seem to have a problem with that (granted, they had some but it's solved now).

Frankly, yes, there may be issues, but I'm confident that the Human race will be able to overcome those.

The LHC's vacuum pipes are 6.3 cm in diameter..

What, really? What's with all those mega photos we see everywhere ?

Most of that is the magnets around the beam tube, with the associated power and refrigeration equipment. The beam tube itself is quite small.

Those are the detectors. And the magnets around the tubes.

This picture shows a cross section of part of the LHC. Those two yellow lines sticking out are the actual tubes. Everything else is equipment to manage the particles (detectors, containment, magnetic propulsion).

And for a sense of scale, a human can comfortably stand in that tunnel next to it.

Image: http://www.tut.fi/cs/groups/public_news/@l102/@news/@p/docum... From here: http://www.tut.fi/en/about-tut/news-and-events/tut-and-cern-...

Yeah, LHC's is the largest in the world at just 15,000 cubic metres -- equivalent to about 1 km of hyperloop tunnel (assuming 14ft diameter mentioned in the Boring Company's FAQ)

I love how you've capitalized "Human", as if to say there were some other race competing to complete the Hyperloop. :)

What about building a high speed train? Proven technology, works in a lot of countries. LA to SF in 2 hours. Is it really that bad?

Someone made the argument that in the US our rails were built by men half killing themselves for low wages and with very few safety standards. That means a modern buildout is much more expensive than it was historically and the political will to build that budget is difficult or impossible.

Hyperloop is a run around that problem. Largely autonomous/low staffed boring that's non-union labor, non-public sector can make a lot of progress quickly. There's no public sector union demanding x amount of jobs, x amount of pensions, and other expensive regulations or union concessions. Musk's Boring Company thinks it can build tunnels for a fraction of the cost privately without much public sector regulatory weight and they might be right.

HSR is the saner idea, but without Congress funding it, its just not going to happen. Obama made a big push for it during the stimulus but more conservative states decided against accepting the money for both ideological and financial reasons. Once enough states say no, then the rail can't go very far, and the project eventually died:

First, Tea Party conservatives in Florida and wealthy liberal suburbanites in the Bay Area began questioning their states’ plans. Then, just as Joe Biden was calling for $53 billion in high-speed-rail spending over the next six years, a crop of freshly elected Republican governors turned down billions in federal money for lines in Wisconsin, Ohio, and Florida. Finally, Republicans in Congress zeroed out the federal high-speed rail budget last month.

http://www.slate.com/articles/technology/technocracy/2011/12...

Re: unions, there are sandhogs unions, wouldn't they be relevant? Ex: http://www.sandhogs147.org/

It'll be more like 3 hours, and it will end up costing around $100 billion. It would be dramatically cheaper and faster to subsidize free plane tickets between LA and SF for the next 50 years.

HSR works well in places with high density and competent infrastructure construction strategies. California has neither.

Trains have a much higher capacity. Most people currently drive the distance which leads to more accidents and a lot of lost time.

$100bn is too expensive to make sense but I don't understand why it should cost that much. There are not that many tunnels needed, esp. if you start/end north of LA and south of SF. European rail projects are also expensive but still a fraction of the cost.

Thermal expansion is at least easy to manage if your system is kept near 0K in operation. It's only an issue when the system is turned off.

I haven't done any work on hyperloops. But expansion seems to be a problem already solved by industry a long time ago: https://en.wikipedia.org/wiki/Metal_expansion_joint

Metal expansion joints can't hold a vacuum.

Quick googling says otherwise: http://www.spiroflex.hr/expansion-joints-vacuum-technology

Sounds promising:

- Resistance to high and very high pressures

- Large movement absorption

- Early leak indication (in case of damage) via standard check hole

- Complete burst resistance

- Possibility of permanent leak monitoring in critical media

> Lots of marketing, very little engineering.

It started as a technical whitepaper, not a marketing campaign, and multiple companies are building experimental models. I don't think this critique is accurate or fair. There have been far worse vapourware and hype-only concepts that haven't gotten close to hyperloop's tangible progress.

No tech can be perfected from the planning stage either, it takes talent, money, and time - and you can't get those things without a bit of hype, the key is keeping it balanced.

Regardless the concept seemed feasible enough to some very smart people and people with money to spend, where they see it's worth the R&D.

I don't really see what the big risk or downside here of exploring this? Considering the rewards could be very high if it does work and otherwise there has been little innovation in transportation in 50yrs, it's not like there are some obvious alternatives are being neglected.

>it's not like there are some obvious alternatives are being neglected

A high speed train like the ones they've had in Europe for a long time? You know, the ones that regularly reach 300 km/h? If that's not fast or flashy enough for you, what about Maglev? It actually exists, and the tracks are extremely expensive even though they don't even have to maintain low air pressure

We have natural gas pipelines that have to maintain a far higher pressure difference, and they are in the same order of magnitude in diameter. They're not expensive. Way less than high speed rail lines per mile.

> A high speed train like the ones they've had in Europe for a long time?

I don't see what the US political inability to build infrastructure has to do with my comment. Plenty of countries are still building highspeed trains and iterating on that model... and plenty of non-US countries are looking into hyperloop, the first ones to adopt it will likely be outside of the US, as that's where most innovation is these days. And regardless there's always plenty of room for new ideas.

Unless you think these billionaires should be backing American transportation mega-projects instead? There's plenty of roadblocks there outside of access to capital, where a highspeed train will likely cost 2-3x the initial projections, even if a private company does it. Not to mention the US is a car-heavy market. It seems like a risky project for any non-government entity to take on as it will be packed full of political risk and direct involvement either way...

The US rarely builds major projects anymore except in the defense industry. And almost every major defense project of comparable size ends up being billions over budget or cancelled.

No, the whitepaper came after the start, which was Musk publicly bragged about how he and his engineers could do the rail project better.

"More marketing than engineering" seems accurate to me.

Out of curiosity, have you ever built anything big? I say this because the tone of your comment is dismissive, however it seems quite low-effort. I can translate your criticisms into criticisms of building subways in 1863:

  - if you build a subway it will be the biggest underground railway ever built.
  - Rocks.  They could fall in front of a subway car and cause a huge accident.
  - safety.  what if all the lights and power go out?  Also how would anyone breathe down there.

And my criticisms seem stronger, not weaker, than yours. Today all cities with robust subway systems benefit hugely from them and all of these issues have been resolved.

The criticism you've offered seems equally low-effort, so this is why I'm curious if you've ever helped design and build any large-scale project.

I don't like gratuitous negativity on HN and it's against the rules here.

Also, planes are a terrible idea. I mean how do you evacuate people from them if something goes wrong? I think this whole airplane thing is just vaporware.

The question isn't "will this ever work?", the question is (while keeping with your airplane analogy) is Elon Musk's design closer to the Wright brothers airplane or Da Vinci's ornithopter. I'd guess the latter personally.

The Wright brothers had a bicycle shop, whereas Da Vinci was more of a painter.

The main thing Musk has in common with the Wrights is running an electric car transportation company and sending private rockets into space via SpaceX.

I think you should revisit whether that makes it more Wright brothers or Da Vinci.

What are you arguing? You wouldn’t take the position that it’s guarenteed to succeed, that seems absurd to me. The person you replied to only made the point that it could fail. And in your reply you actually took the opportunity to degrade artists and thinkers, which seems cruel and unnecessary.

You’ve found a flaw, I think a pedantic one, in the example they gave.

Here’s an example that is less flawed, and I think if you had considered their point rather than sought minute flaws you could see this yourself: the palm note vs the iPhone. Hopefully, even if my analogy is not literally flawless, you can take my point.

Also, sorry for spamming you, something you wrote struck me and I wanted to see what else you wrote. Hope you don’t mind this.

That isn't exactly a solved problem though. Almost all of the time it's "everyone dies". We just have failure rates low enough and it's convenient enough that people accept it.

This is normal. You either handle failure gracefully or ensure the failures are very rare.

The question is if we want to accept the risks. In the early days of subways, trains, planes and cars, accidents were frequent and many people died until we figured out the safety aspect. Today's society is much more risk averse. I don't think the general public would accept several fatal crashes before the system is safe.

It's easy to come up with reasons why something won't work.

But, usually, it's more productive to start with the understanding that other people are smart too, and that they may have thought of these problems. In this particular case, I believe that the original white paper addresses these points. I'm not a structural engineer, so I've no idea if their solutions are valid and I'm not saying that it's never okay to criticize, but this reads to me as if you may have fallen into the trap of forgetting that the people who designed this are very smart people, and thus likely thought of the obvious problems.

Just as a thought experiment, could the promotion of these "hyperloop" projects be a clever political ploy to misdirect/divert attention and prevent a viable high speed rail network from being built?

Elon's main business is electric cars and (one of) Branson's is airlines. So a reasonable competitor to both is fast and cheap(er) public transport along a major travel corridor in the USA.

This means that by promoting this alternative to high speed rail as faster, cheaper, better, they are undermining public support for a real project, which could mean its end.

Branson's also in railways – Virgin Trains.

I think Branson gets into almost everything, like a bigger form of an Angel investor. In that regard it makes sense to use the brand and money to make many small seed stage investments.

Interesting idea. In Denver, they're partnering with our regional transportation district to evaluate a hyperloop system here. Unfortunately RTD has been completely incompetent with existing rail programs to date so there isn't much confidence in their ability to pull this off. Could potentially be designed to fail.

Yeah, Denver being chosen just convinced me that this whole thing is pump and dump cash grab.

CDOT has this thing for "public/private partnerships" which are just thinly veiled schemes siphoning off taxpayer money. The whole US36 debacle proved to me that they aren't capable of negotiating a good deal on the part of the taxpayers.

What whole thing? The Denver partnership was made by Hyperloop One, which is just one of the companies trying to build it, and is not affiliated with Elon Musk.

Sure, 'the whole thing' being Hyperloop One in this case.

It's a good thought experiment, and not without precedent.. however the main problem holding high-speed rail back in the United States is that freight trains have priority over passenger trains.

Without changing this, high-speed rail in the US will never be a reality without building an entirely separate rail network.

Isn't that because the freight companies are the ones that actually built, own, and operate the tracks? If Amtrak or another passenger company owned the tracks, their trains would get priority.

On land gifted to them by the government.

Given the key function railroads had in opening up the west, I think you'll struggle to argue that that was even close to a bad deal.

Indeed, that, if anything, is exactly the kind of investments that a government should be making.

nongovernment investments tend to be more sustainable, because they are driven by observed demand, instead of cronyism or politics. This was one of the few railways to survive the great railway crash, it's still operated today:

https://en.wikipedia.org/wiki/Great_Northern_Railway_(U.S.)

> This was one of the few railways to survive the great railway crash

The government well made its money back before the great railway crash.

Let's say the Internet suffers a crash in a few decades. Few would argue that any previous investment into the Internet was not worth it.

you're cherry picking an example that succeeded. Let's say DARPA's investment in ESP doesn't turn out in a few decades. Few would argue that any previous investment into ESP was not worth it. (disclaimer: I'm being paid on a stupid darpa grant now)

Non-governmental investment - except for the 3 million acres in Federal land grants.

If in the mid-19th century these were gifted to the railroad companies as 99 year leases, the value to the companies wouldn't have been very different, but we wouldn't be in thrall to them today.

and what if the railroads looked at the 99 year lease offer and said, "no thanks fam"? What if is such a pointless game to play.

99 year leases have been very, very common throughout history. Simply doing a present value calculation yields the result that to an investor, a 99 year lease and a 999 year lease are approximately the same value today.

The land grants weren't for the land that the railroads ran on. It was for adjacent property that they could develop or sell. And not all the transcontinentals relied on land grants (e.g., Great Northern).

No, Amtrak supposedly has priority by law: https://www.washingtonpost.com/news/powerpost/wp/2016/04/29/...

Yes, and that law didn't come out of the blue. More pertinently, a purpose built passenger rail line will have priority for passengers.

Based on this article, I'm under the impression that the law was overturned. The most recent article I can find about the status of adjudication suggests that Amtrak will have a very difficult time upholding that law: http://lyldenlawnews.com/2016/09/22/u-s-faces-a-choice-on-am...

Are they?

AFAIK, passenger trains have priority. However, if the passenger company rents a specific timeslot from the railway and isn't on time, it isn't surprising if there is traffic along the way.

And high speed trains usually require dedicated tracks to operate at full speed anyways.

And straight track runs for really high speed. Which means that you need to acquire land to build through.

I was also under the impression that freight trains had priority, so I looked and found this article:

http://www.sfgate.com/opinion/article/Amtrak-has-priority-ov...

I've experienced these delays many times riding the California Zephyr, and the conductors always say something about the freight trains having priority. According to the article this is because Amtrak is persistently ceding priority, despite federal regulations prioritizing passenger trains.

edit: According to the WaPo article linked by jey in this thread, this ended up overturned in federal court, so I guess as of 2017, freight does have priority over passenger trains in the U.S.

or they see that trains are the future and they want to own those trains.

Why would Elon have sparked the idea in the fist place, then?

It wasn't entirely novel, but he gave the idea legitimacy beyond the normal fantastic imaginary future one is wont to see from time to time.

So I don't think this was an attempt to head the tech off at the pass or some alternate reality like that.

I think it was genuine and continues to be.

Of all the problems facing construction of "viable high speed rail" in the US (they already exist in many other places), I don't think Hyperloop competition is among ... the top 50.

Practically anything could be "a clever political ploy", but where's the evidence for this? Any in the absence of such evidence, why speculate?

Just as a thought experiment, could HN user daemin's comments be part of a clever ploy to invent a fake persona to distract from a SECRET AGENDA? ;)

We're just building a new major high speed line in the UK, and you'd be surprised how often you hear people say that it shouldn't be built because the technology will be superseded by the hyperloop, or autonomous cars, or whichever. It's one of the major talking points, even if it isn't one of the major blocks.

its things like these which make it seem like a clever ploy. However cool a technology hyperloop seems like. it is nothing more than a research project with a great marketing stunt.

Meh. The imminency of "Major New Technology Just Around The Corner" has always been a favourite argument for the anti-progress crowd.

EDIT to add: Before Hyperloop, it was Maglev.

And frankly, a significantly better argument against HS2 is that it's an impossibly expensive boondoggle.

> a significantly better argument against HS2 is that it's an impossibly expensive boondoggle.

Nah, it connects most of England's largest cities, and will be 2/3rds of the network which will connect all of the cities of the North of England into something approaching a single labour market. Liverpool, Leeds, Sheffield, Manchester, Birmingham will be all be within 30-50 minutes of each other, with London within an hour and a half, with trains running between destinations 2 or 3 times an hour. The value of that is enormous.

It would have been politically a LOT easier of they'd built a Birmingham-Newcastle leg first

and probably better for the long term economy as well; the last thing Birmingham needs is a reason why London is a good base for doing business in Birmingham.

This is a pet peeve of mine. It hurts not just the other cities in the UK, but London as well. We don't alleviate overcrowding in London by making it easier to move to London. We alleviate overcrowding in London by making more other locations economically stronger.

That should mean strengthening a region around Birmingham, faster links connecting the Leeds - Sheffield - Manchester triangle + tack on Liverpool, and a wide orbital around London improving connections between the towns around London that now are reduced to feeder/sleeper towns. There are towns around London that has decent direct rail tracks, but where the fastest rail route is a 2x-3x longer journey in to a London terminal and back out again. Actually run direct trains, and you suddenly have new viable commuter regions that bypass the centre.

Only after that should we think about making the links between these centres faster.

The problem of course is that many of these will need to be run at substantial losses for years before enough companies etc. will move/get established to change transport patterns, and it's so much easier to justify building more expensive routes where there is existing overcrowding.

Never mind that doing so just attracts more people.

Perhaps. There would also have been political costs incurred due to the overcrowding on the southern end of the WCML and that then being apparently a lower priority than providing a quicker link between two cities.

And yes, I realise the XC trains around Birmingham (inc. to Newcastle) are frequently overcrowded, but there's a comparatively cheap solution to this: buy more trains.

The main point of HS2 is that it will relieve congestion on the existing tracks, and allow more commuter services to run:

https://www.railengineer.uk/2014/01/03/the-capacity-benefits...

http://www.citymetric.com/transport/hs2-isnt-about-north-eng...

The idea that it will turn a load of separate cities into one big city is basically fantasy, as i understand it - this is about HS3, but the analysis is much the same:

http://www.citymetric.com/transport/crossrail-north-really-b...

And yes, i do get all my information from CityMetric, since you ask. It's basically Buzzfeed for transport policy, i love it.

Yes, I think this is it. I don't buy into any "clever political ploy" theory, but this type of stuff does get into people's heads. The rise of Uber and Lyft are already being used in arguments against mass transit.

Same here in India. People oppose hsr train as a waste of money in favor of centuries old infrastructure. The same people also believe that if we should move to a new technology, it should be hyperloop, rejecting maglev on the way. They either want current infrastructure to be maintained, or pie in the sky dreams.

Exactly.

It's not competition from Hyperloop that's in consideration. It's the diversion and absorption of public demand and political capital. If people think Hyperloop is in the works, they are less likely to ask for high speed rail. And politicians are less likely to become banner carriers for high speed rail in such a situation.

Not taking a side here, but it doesn't seem useful make fun of the parent comment for what, on its face, seems to me as a pretty apt comment.

These two gentlemen stand to gain from the failure of mass long distance transit. So, why are they spearheading any kind of Hyperloop project? It's a valid question, and the suggestion about their motive is not farfetched for a couple of successful business magnates.

> Just as a thought experiment, could HN user daemin's comments be part of a clever ploy to invent a fake persona to distract from a SECRET AGENDA? ;)

If that were the case it would be one hell of a troll, set up an account for many years just for this one incident!

> Practically anything could be "a clever political ploy", but where's the evidence for this?

I mean, Musk's initial announcement regarding the hyperloop was about how California high speed rail shouldn't be built. These are the first lines of his blogpost announcing the hyperloop[1]:

> When the California “high speed” rail was approved, I was quite disappointed, as I know many others were too.

We can debate Musk's motivation, but the fact remains that the hyperloop is being used to argue against high speed rail construction, and has been since it was first announced.

[1] https://www.tesla.com/blog/hyperloop

More likely, it's Elon worrying about how to colonize Mars than anything else.

There is some public support for high speed trains?

Hyperloop at least started a discussion. Once it fails, there might be some actual public support.

There is tons of support for high speed rail. California's voters passed a bond initiative to fund one stage of it. Whether voters would vote to raise taxes to fully fund it is another question, but voting for $9 billion in bonds cannot be interpreted as anything other than public support for high speed rail.

Just because there are significant interests that oppose high speed rail at every turn doesn't mean there isn't public support.

I think it would be a good idea to make sure the California "high speed" rail program is never funded. It is a terrible idea. As it stands, it would be as slow as conventional rail, redundant with AmTrak, and the most expensive rail line ever built. It would be absolutely devastating for the government's relationship with at least tens of thousands of land owners, hundreds of thousands of home owners, who would see depreciation or outright loss of use of their land (which may hold sentimental or historic value not accounted for, or impossible to account for, in eminent domain assessments).

It's not redundant with amtrak. There's no way to get from LA to SD on passenger rail without transferring through busses.

That should be SF, not SD.

The Coastal Starlight runs from Union Station in DTLA to Jack London Square in Oakland. From there, it's a quick walk to BART to get into San Francisco - no bus required.

That being said, the trip takes 13 hours and some change, depending where in SF you're trying to go - which would be blown out of the water by HSR.

That must be new. That wasn't available as of like we years ago or so.

That rail route has ran continuously since 1971: https://en.wikipedia.org/wiki/Coast_Starlight. The transbay tube connecting Oakland to San Francisco via BART opened in 1974.

it's worth noting that coast starlight's once-a-day-each-way schedule sort of makes it limited as a commuter rail option.

Its too long and slow to be commuter rail anyways. The Bay Area -> LA segment takes about 12 hours (of a total 35ish), if its on time (its often multiple hours late). Even if it was never late and left every hour, it wouldnt be a very practical commute.

It is fun if you enjoy trains though! Take it if you have the time.

+1. I took it once, and it was a wonderful time. Jump for the business class seats, they aren't much more expensive and are quite nice.

But yes - absolutely terrible from a commuter perspective.

"it would be as slow as conventional rail" - citation?

Even Reason Foundation (which is as biased as it gets - it's funded by Koch brothers and ideological critic of almost any government investment) claim SF to LA times will be 3:30 to 4:40, which is faster than any train today.

That's barely faster than driving, once you account for the time spent moving between your origin/destination and the train station as well as transferring luggage.

An under-four-hour train trip still sounds like a win over a six-hour-with-good-traffic drive. Especially for people who don't really like making that drive, which I suspect is a substantial subset of the population. (I like driving, personally, but that trip is decidedly less than a thrill.)

In the near age of driverless cars I think this might be its biggest demise. If cars are automated people wouldn't need a train. It will be cheaper and less confining to a schedule and to a destination.

I think air travel for short to medium flights will fall off. By the time I leave my house and get to someplace that is 8 hours by car it would take 5 hours to check in and check out and you still need to rent a car.

Autonomous vehicles do not obviate grade-separated transit options. Even if we imagine a road network populated only by highly efficient and inter-connected autonomous vehicles, the increased capacity allowed in such a situation will only create more demand, which will scale up traffic problems.

Now, other than traffic, I agree. When deciding whether to drive somewhere or take the train, my second factor is whether or not I feel like actually driving a car. That answer is usually no, so I'm very excited about driverless cars.

The real benefit, in my opinion, from autonomous vehicles is that they remove a major barrier for a lot of people to not owning one. By taking drivers out of the equation, you can cut cost or increase vehicle availability or both to the extent that being able to get vehicles urgently, or cheaper, depending on need, can give most people in densely populated areas an experience close to as good as owning a car. Better if multiple people need to go different places.

And while you're right that this will probably drive up demand, it achieves something else too: Availability of extensive route information. Now imagine a shared system for such cars to negotiate routing, and such cars can know which routes will be less congested, and can know which cares it is most effective to re-route because of where they're going.

E.g. there's a chokehold near me for Southbound traffic that it's tremendously beneficial to bypass if you're heading South-East, because you can take back-roads with lower speed limits but that are shorter, and that will end up being much faster when the chokehold is congested. Which it "always" is between certain hours. But if you're going South West, it's better to suffer through it.

With vehicles able to negotiate route information, vehicles going South East could be automatically re-routed when there's congestion, resulting in average speed improving for everyone.

In fact, you could even imagine a system where cars autonomously negotiate a fee for other cars to let it get in front (so you could e.g. pay a 30% premium for urgent trips and have the car company spend, say 25% to buy its way in front of others on congested routes).

This may not entirely solve the problem, but it can make congestion more about total throughput than maximizing throughput on a small number of routes.

End-to-end route information also opens the door for services to mediate multi-step routes with e.g. cars feeding public transport much more efficiently (e.g. in my case I live almost exactly halfway between two major rail stations, with two more small ones not much further away. I almost always opt for the largest of the four because it's at a central junction that gives me the best option for almost every destination so I rarely need to think about it, and it also means I know exactly how long it takes me to get there.

But if I can tell an app where I want to go, and get told to either go to the bus stop or wait for a car, get taken to whichever station is the best option and told which track/train to take, and get picked up by a car on the other end, there might be substantial time savings and often a better shot at a seat. The only thing stopping me from "shopping around" like that today is that it's extremely inconvenient.

Again combine that with pervasive end-to-end route information, and you can make it even better by ensuring not too many people get routed onto each train if two options are relatively equal and one is less loaded.

And taking the light rail north of SF to the ferry and then the Embarcadero in SF takes longer than driving when my brother commutes, but he still chooses that method. Perhaps there are factors other than time that go into his calculation.

People would take HSR even if it took the same time as driving. They would likely take it if it took an extra 20%, as the time has more utility to them when used for a train ride. That it's actually faster than driving just makes it more attractive.

Agreed. Many people underestimate the aversion of a large swath of the population to driving. Driving basically monopolizes your time and focus and exposes you to accidents. I don’t know if I know anyone who would rather drive if they could get to their destination in the same relative time, unless they’d need a car on the other end.

Who doesn't need a car in LA though? LA has terribad public transit, if you are planning on renting a car on the far end you can probably afford to fly too.

Oh goodness. Monopolizing your time is part of the value of driving, for me - it gives me something to do while I'm waiting to arrive at my destination!

The difference is that your brother is commuting for the day whereas with HSR half the tickets are for people to arrive in LA without a car.

3 and a half hours is way faster than driving. And for the comfort of being on a train? Worth it!

> I think it would be a good idea to make sure the California "high speed" rail program is never funded.

Never funded? It's already under construction[1]. Although it's likely pre-pre-pre-construction, as they grade items and fix obstacles for the actual railway construction, which I doubt will happen within a decade, if ever.

1: https://www.buildhsr.com/interactive_map/

> Although it's likely pre-pre-pre-construction

They're building the bridges right now, that's not exactly pre-pre-pre-construction.

It's a great idea and I can't wait to see more high speed rail built all across the country.

We've already criss-crossed uncountable acres of historic, sentimental (what?? really??) land with roads, both local the state/federal highway system. HSR would be so much better use of land than roads, for moving a lot of people quickly and comfortably. Not at all redundant with Amtrak.

Happily, the California project is funded and is already underway, and I think there's one or two others being talked about/planned.

On top of that, my experience of (southern) Californian roads is that they are muuuuuch wider and take up much more space than the coaster/amtrak train tracks take up, so roads have been much more damaging to historic sentimental land than rail is or would be.

What really irks me with that particular sentiment (the land is historic/already in use) is how the federal highway system absolutely decimated communities of color in a lot of major cities.

They'd put a highway right through where the black folk live, and who cares? Well, all the people in that neighborhood care, but they're poor minorities--they have no political power, no ability to push back.

If you want to start talking about land being taken from people, don't fucking start with farmers in rural California and HSR, start with the inner city neighborhoods the highway system destroyed.

Who says I agree with either?

Of course it is. Organizations that benefit from road infrastructure expansion actively work to discredit and defund government transit initiatives.

Historically there is the example of 1920s era GM funding initiatives to convert tram lines into bus lines, which required further investment in road networks, which benefited their private car ownership business as transit was defunded and discredited.

All Branson has left is a partial holding of Virgin Atlantic on the flying business side of things. Virgin is in the train business, and has 100% holdings there, so if anything he has more business interest in seeing high speed rail come about.

They also have a small stake in Virgin Australia (not that this in any way contradicts your point).

High speed rail already was not going to happen in the US for large political and practical reasons. Having a master plan to kill American rail travel just sounds like a waste of time

Transpower in nz used this argument to drastically cut its maintenance budget in the 90s using "distributed generation will strand the assets" type reasoning. Nz suffered the consequences. Who pays taxes and who booked imaginary accounting profits is left as an exercise for the reader. So yeah, it's not obviously wrong as a concern.

Musk literally wants to colonize Mars in his lifetime. Do you think that claim is a clever strategy too? Why is the hyperloop where people draw the line at credulity?

Highly unlikely.

Branson's Virgin Group owns only 20% of Virgin Atlantic (don't let yourself be mislead by the Virgin name appearing all over the place - Virgin tends to start businesses, sell all or part of them when the opportunities are right, but continue to lease the name out to the buyers; the Virgin brand appears on dozens of companies with little to no Virgin Group ownership).

In 2016, Virgin Atlantic's revenue was less than 3bn GBP, with Virgin Group's "share" of that, just 600 million GBP (yes, I know it doesn't make sense to count it that directly; if looking at operating income instead, Virgin Atlantic's operating income in 2016 was ca. 150mn GBP), while Virgin Group's revenue was 20 billion pounds. So Branson's airline interests are relatively minor in the grand scheme of things.

And Virgin Atlantic would not face much competition from high speed rail (the clue is in the name - Virgin Atlantic might in fact very well benefit from a high speed rail network if it meant the ability to offer customers faster/easier access to more of the US with fewer US destinations which would make it easier for them to compete with airlines with more comprehensive route networks).

Virgin Group also wholly owns a UK train operator - if they saw "regular" high speed rail as a good business opportunity in the US, odds are higher they'd invest in it than try to stop it.

As I replied to an earlier sibling comment, Richard Branson tends to invest and distribute the Virgin name to a lot of companies, like a bigger angel investor that also helps with branding and marketing.

Also a lot of them end up going nowhere, much like with other Angel investing.

But that is different to what I replied to, which was the question of whether he'd have a vested interest in trying to stop high speed rail.

How about we stop letting politics destroy our future? Accusing someone of political reasons is a sure-fire way of derailing public discussion on a topic.

That's not a "thought experiment", that's a "conspiracy theory".

The original Hyperloop paper quotes its design pressure as “about 1/6 the pressure of the atmosphere on Mars” [1]. Martian atmospheric pressure is “about 0.6% of Earth's mean sea level pressure” [2]. So 0.1% of Earth’s surface pressure, or a 1,000:1 pressure change.

To put that in perspective, the Boeing 787’s GEnx-2B67, the most powerful GEnx engine variant, generates a 43:1 pressure ratio [3]. To get a sense of the engineering differences between 6:1 and 1,000:1, look at NASA’s Space Power Facility [4].

The Hyperloop’s thermal issues are a hard enough problem that they alone put this in the domain of materials science. That’s the same category of problems separating us from a space elevator.

The Hyperloop always seemed like a transportation system not for this planet. The thermal issues, too, become trivial to solve on Mars: bury the tube. Mars does not appear to be too seismically active [5] and has no existing property rights to take into account [citation needed]. (The lack of water also makes steel more viable.)

[1] http://www.spacex.com/sites/spacex/files/hyperloop_alpha-201...

[2] https://en.m.wikipedia.org/wiki/Atmosphere_of_Mars

[3] https://en.m.wikipedia.org/wiki/General_Electric_GEnx

[4] https://en.m.wikipedia.org/wiki/Space_Power_Facility

[5] https://www.space.com/418-marsquakes-red-planet-rumble.html

Some colleagues of mine also did a short feasibility assessment of the original white paper, and came to some similar conclusions. The propulsion system also made some assumptions about compressor performance that seemed too optimistic compared to existing turbomachinery.

That said, I have not followed closely enough to know if the hyperloop startups out there are following the original conception or if it has significantly evolved or not. I hear that they've ditched the compressor altogether, but that's got to have a pretty big impact on expected speeds.

> Some colleagues of mine also did a short feasibility assessment of the original white paper, and came to some similar conclusions

Likewise. It sounds like above-surface (on Earth) is probably unfeasible given (a) security and (b) thermal concerns.

For security, we just contemplated debris from the track (or a bullet from an errant rifle) puncturing the tube. Hyperloop One is testing an 3.3m diameter and 500m long track [1]. That's 4,276 cubic meters [a]. "At sea level and at 15 °C air has a density of approximately 1.225 kg/m3" [2]. The air in the Hyperloop One test track thus weighs about 5,200 kg.

If we use the Hyperloop's original design spec [3], a puncture means air on one side at 1 atm expanding into the space on the other at 1/1,000 atm. This simplifies to a wall of air moving at just below the speed of sound. Since the speed of sound is about 330 m/s [4], the end of the tunnel will could hit with a pulse with about 140 megajoules of energy [b]. That's the energy in about 30 kg of TNT [5][c].

> I hear that they've ditched the compressor altogether, but that's got to have a pretty big impact on expected speeds

It currently sounds like a vactrain [1] with magnetic levitation [2].

[1] https://arstechnica.com/cars/2017/03/hyperloop-one-shows-pho...

[a] pi * (3.3 / 2) ^ 2 * 500

[2] https://en.wikipedia.org/wiki/Density_of_air

[3] http://www.spacex.com/sites/spacex/files/hyperloop_alpha-201...

[4] https://en.wikipedia.org/wiki/Speed_of_sound

[b] (1/2) * (5200 / 2) * 330 ^ 2

[5] https://en.wikipedia.org/wiki/TNT_equivalent

[c] (140 * 10^6 / 4.184 * 10^9) * 10^3

[1] https://en.wikipedia.org/wiki/Vactrain

[2] https://en.wikipedia.org/wiki/Maglev

"a wall of air moving at the speed of sound"

What? Particles moving in through a hole against vacuum will usually be travelling at a distribution of speeds dependent on ambient temperature, usually a boltzmann distribution. It will not be a wall, but rather a gradient.

It's also not so much a maglev as an inductrack, which has only really become possible recently since it's come off-patent.

> What? Particles moving in through a hole against vacuum will usually be travelling at a distribution of speeds dependent on ambient temperature, since T = v_rms

A proper answer merits CFD. Barring that, sure, one can adjust for the velocity distribution [1] and the fact that a vena contracta [2] will reduce initial flow rates.

I used 330 m/s, the speed at 0 °C (which is generous since these tracks will likely be operating in hotter conditions), which one will observe is around the molecular velocity of oxygen or nitrogen.

[1] https://chem.libretexts.org/@api/deki/files/68415/BolzDist-M...

[2] https://en.wikipedia.org/wiki/Vena_contracta

sigh another "deadly wall of air" theory ala Thunderf00t? Hasn't this been debunked already?

"A little bit of physics is a dangerous thing."

* A bullet or piece of debris would likely leave a hole much smaller than the diameter of the tube. A breach 1/10th the diameter of the tube will admit 1/100ths as much the air.

* Even if there was a whole-tube breach, the "wall of air" will rapidly slow down and smear out into a gradual pressure rise due to friction with the tube walls. Pipes are not lossless! Within 5 km friction will have the air moving at highway speeds. So if you're so close that you can be killed by the air blast, you're so close that the pod can't brake before hitting the whole-tube breach (bad). In other words, "deadly pressure waves" don't increase your odds of dying beyond that of a regular "derailment" event.

* In the event of a breach (whole-tube or otherwise), sensors in the track will signal all the pods to stop and the tunnel to undergo emergency re-pressurization. So any "wave" won't get far.

> ala Thunderf00t

Just watched one of his videos on this--interesting and thank you for the pointer. Agree with you on his overstating the deadliness of pressure pulses. 30 kg of TNT is a lot of energy, certainly enough to knock your infrastructure out of commission for a couple days. The "everyone dies if the tube is punctured" argument is hyperbolic, though.

The materials science problem is the thermal expansion. And not the longitudinal one that Thunderf00t mentions. It's the transverse expansion. If these are above ground, the top will heat up relative to the bottom. That's a nasty problem to solve while maintaining the structural integrity to keep a giant vacuum with speeding capsules in place.

> It's the transverse expansion. If these are above ground, the top will heat up relative to the bottom. That's a nasty problem to solve while maintaining the structural integrity to keep a giant vacuum with speeding capsules in place.

Right... you can probably solve that with a bucket of white paint. Worst case you cover it with an aluminum shield- aluminum does not absorb infrared radiation and will reflect 99.9% of ambient heat. Since the proposal included covering large sections of the tube in solar panels that isn't even a significant change.

> you can probably solve that with a bucket of white paint. Worst case you cover it with an aluminum shield- aluminum does not absorb infrared radiation and will reflect 99.9% of ambient heat

It's, unfortunately, harder than this. It's a similar problem to the ones we dealt with regarding rockets, standing fueled, on a pad. Both methods you propose were tried. The solution is to (a) paint it and (b) launch before the gradient becomes too big.

The stresses on the Hyperloop tube, when a capsule is rushing through it while it's containing a near vacuum, are comparable to those on a rocket nearing max Q [1]. The difference is with a rocket we take great care to maintain symmetry. With the Hyperloop, that isn't an option. That persistent asymmetry is what makes it a difficult materials problem, particularly if we're using any known metals (even wonderful light and thermally-conductive aluminium).

[1] https://en.wikipedia.org/wiki/Max_Q

Dude, what. That's bullshit, and the size difference will be on the order of dozens or low hundreds of microns. Not only that, but the distortion will be spread evenly across the tube because it's a tube. You're just asserting that putting the tube in shadow will somehow not block heat from the sun.

I'm also not sure you understand what I'm saying about an aluminum shield? Aluminum has an emissivity coefficient of .04. Thermal conductivity has nothing to do with it since it isn't touching the tube. It's purpose is just to not re-radiate infrared onto the tube.

I think what we have here is someone applying a known problem and solution space for one industry (rocketry) to another (civil engineering). A large vertical tube that needs to move quickly and under great stress may not allow for the same solutions that apply to a large horizontal tube that is relatively static.

Fixing a large enough solar shield above a rocket hundreds of feet in the air which has to get out of the way quickly before the rocket launches has very different requirements than fixing a shading structure above a vertical static structure a few tens of feet in the air. I'm not sure how this problem was solved in rocketry is necessarily indicative of how hard it is to solve in other circumstances.

> I'm not sure how this problem was solved in rocketry is necessarily indicative of how hard it is to solve in other circumstances

Very fair. The advantage a rocket has is you choose when it's rolled out. You don't have to design for the worst weather because you can always hide.

You can't do that for a static structure. The Hyperloop is an attempt to marry the challenges of rocketry to the standards of civil engineering. The advantage is you don't have to think about aerodynamics, which is good, because air is the worst. (You also get civil-engineering budgets.) The bad is you can't hide from the edge cases.

If you want to grapple with this problem live, rent (or borrow) a thermal camera and make a model. Aluminum or tin foil would probably work for something on the window. I've only done this upright, to simulate storing an unfuelled vehicle outdoors in "ready-to-launch" mode, but you'll run into similar problems with a horizonatal configuration. At first, the shade works. Then thermals develop. You can foam it, and that looks like it works for a few days. Then someone instruments the inside and, lo and behold, hot spots. Turns out foam doesn't really help with heat that recurs in the same place, day after day. (Our solution: slowly rotate it.) You could completely isolate the tube, which is what NASA does in its vehicle assembly building [1], but at that point you might as well (a) bury it or (b) have a fleet of Concordes flying on loop, because either will be cheaper.

I'm not saying it's impossible. But it's much harder than the pressure problem, which is itself hard to get economical. If you want the tube above ground, I don't think it works with existing materials. My criticism of the Hyperloop One project is they didn't bother solving these issues with models. (Note: this is how Elon did it with the Falcon 1.) Instead, they decided to build a maglev track.

[1] https://en.wikipedia.org/wiki/Vehicle_Assembly_Building

So, to make sure I understand the problem correctly, you expect thermals to develop under shaded portions that still cause heat, and that to affect the structure's top and bottom heat differential to a degree that it would still cause problems? Is this different than oil pipelines because of the low pressure and lack of a heat transferring medium to even the temperature of the tube? I'm trying to figure out how this would affect a proposed hyperloop system, when it seems sufficiently solved for other above ground pipeline systems.

I can see relative size, inside medium, building material differences, shading structures and acceptable tolerances all affecting the outcome one way or the other, but I'm not sure to what degree each one would affect the outcome, so I'm not sure if it's actually as hard as you make it sound or whether a solution is known and achievable.

> Is this different than oil pipelines because of the low pressure and lack of a heat transferring medium to even the temperature of the tube?

Most hydrocarbon pipelines run HTHP: high temperature, high pressure. This keeps their contents viscous. That, in turn, means heat emanates relatively uniformly from inside the pipe. For pipelines subjected to asymmetric expansion (e.g. when starting up or shutting down), they "walk".

"Walking behaviour occurs as the pipeline is heated, and expands asymmetrically, until the point when pipeline expansion is fully mobilised. Expansion is ‘fully mobilised’ when a virtual anchor forms near the centre of the pipeline. The virtual anchor is then stationary, while pipe to each side expands away from the anchor as the temperature continues to rise. Once expansion is fully mobilised, walking ceases for that cycle." [1] As long as it walks laterally, pipeline owners tend to be fine with it

The solution to walking is typically laissez faire (taking care to ensure the deformation occurs laterally, i.e. side to side, versus sticking a butt up into the water.) Needless to say, this isn't an option for the Hyperloop.

Granted, the contents of these pipes operate at 130º to 170º C. They're also narrower, resist a smaller pressure differential, face fewer such asymmetric events and don't face the stress of capsules periodically whizzing past inside them. Our tube won't displace by meters. Its displacement, moreover, won't be problematic on day one. But over time it will critically weaken known materials. Big, dynamically mechanically stressed, close to vacuum and above ground is hard.

[1] https://www.researchgate.net/profile/David_Bruton/publicatio...

yeah Thunderf00t's hyperloop video is dumb, moreover, yes a lot of pressure can cause a tiny metal bearing to punch through a glass tube but the net force distributed over a mass scales with the size of the object squared, but the mass scales with the size of the object cubed. So the effects of pressure on a tube 2 meters wide is going to be far less dramatic than one 2 cm wide.

> If these are above ground, the top will heat up relative to the bottom.

The heat will quickly conduct to the other side. It's one of the main reasons for choosing steel. Add white paint to that (or solar panels) and you'll have reduced heat absorption to a minimum.

> The heat will quickly conduct to the other side

I take it you haven't had the pleasure of watching carefully machined cylinders buckle in the Arizona sun :). White-painted aluminum and shaded, mind you.

Those were structures on the order of meters. These problems become nasty with scale.

Weren't there published papers by NASA scientists proving, without a doubt, that it's impossible to construct a booster rocket with the structural stability to return to earth?

I'm willing to give this guy the benefit of the doubt considering his track record. It's also instructive to read the comments when the original Hyperloop idea was published. Even the people thinking Musk would fail were in the minority, because everyone was certain he had no plans of even trying.

> Weren't there published papers by NASA scientists proving, without a doubt, that it's impossible to construct a booster rocket with the structural stability to return to earth?

No. Going back to the 1960s, re-usable two-stage configurations were being drafted [1].

[1] http://papers.sae.org/640297/

But I thought this all came to our god king in a dream.

oh stop. People are excited about reusable rockets, a mainstay of science fiction since the beginning. Why do you have to be a wet blanket? "Elon Musk didn't think of reusing rockets, and he didn't personally build them, and he doesn't have a degree in rocketry!" You're fighting a Quixotic battle against a strawman.

I think reusable rockets are cool, and I think musk is impressive.

I'm just not a member of the cult of Elon. I think he follows a path of aim impossibly high, be happy with getting pretty far. People instead take it as "he's literally going to do everything".

I see many more people talking about "the cult of Elon" than people who actually think he's literally going to do everything.

It reminds me way more of the nickelback is terrible thing. It's more of a meme than the actual subject. It's fun to feel like a member of the enlightened in-group that doesn't follow Elon Musk like sheep. All those dumb people that think GM will go bankrupt next year.

Wait, who said that they need to compress the air all the way to Earth pressure?

None of your critique makes sense without that assumption, and nowhere in your post do you say where that comes from.

> Wait, who said that they need to compress the air all the way to Earth pressure?

No one. The Hyperloop alpha paper explicitly contradicts this assumption on page 18, where the flow diagram gives the compressor input at 99 Pa and the output at 2.1 kPa (a 21:1 pressure ratio).

http://www.spacex.com/sites/spacex/files/hyperloop_alpha-201...

> The Hyperloop alpha paper explicitly contradicts this assumption on page 18, where the flow diagram gives the compressor input at 99 Pa and the output at 2.1 kPa (a 21:1 pressure ratio)

One standard atmosphere (atm) is defined at over 100,000 Pa [1]. The 21:1 pressure ratio in Figure 11 on page 18 is for the "passenger plus vehicle capsule" [2]. I'm talking about the tube.

Going from 99 to 2.1 isn't hard. Going from 100,000 to 100 and then keeping it there is.

[1] https://en.wikipedia.org/wiki/Atmosphere_(unit)

[2] http://www.spacex.com/sites/spacex/files/hyperloop_alpha-201...

But that's no challenge at all. You're just describing a usual vacuum pump. And just a single-stage roughing pump (Harbor Freight, anyone?) can get down to less than 1 Pascal, so 100Pa is a piece of cake. That's only needed for slight leaks in the tube, not for the pod itself.

Keep in mind that the absolute pressure difference is far less for Hyperloop than for a typical natural gas pipeline, and yet the latter can keep leaks to an absolute minimum in spite of thermal expansion, etc.

> You're just describing a usual vacuum pump

Scaling is hard. The largest vacuum chamber we've built is a fraction of the size of the proposed Hyperloop. It was a very, very hard problem [1]. It's expensive, sucks up loads and loads of power and needs lots of thermal management, structural reinforcement and vacuum-off maintenance.

> Keep in mind that the absolute pressure difference is far less for Hyperloop than for a typical natural gas pipeline

Pipes are pressurized from the inside. See my comment from elsewhere in the thread on why vacuums are different [2].

All this said, I generally agree with you. I don't think building a giant vacuum is beyond current technological capability. I do think building one structurally sound and thermal-expansionwise stable enough to carry passengers at high speeds is.

[1] http://teamcorporation.com/images/technical_documents/Space-...

[2] https://news.ycombinator.com/item?id=15459873

That vacuum chamber has two sets of fifty foot tall doors. The hyperloop is an inch-thick welded steel tube. Pinholes are trivially detected by ultrasonic testers. There are no leaks. Even hydrogen and helium would take centuries to diffuse inside. The only problems are sealing the ends, which are a couple meters wide.

The hyperloop as written was very challenging, but the engineering aspects are not. The practical building (grinding the inside, transporting the tubes, etc.) are significant. The financing is insane. The theory is not even particularly hard, much less at the level of a space elevator.

>The largest vacuum chamber we've built is a fraction of the size of the proposed Hyperloop. It was a very, very hard problem [1].

Do we really have to say that a long extruded tube that only has to maintain low vacuum is a lot simpler than the SPS?

SPS: big thing made up of many custom one-off parts that runs at 1/380,000,000ths of an atmosphere and can blast test articles with intense simulated sunlight.

Hyperloop tunnel: big thing made up of many identical parts that runs at 1/1,000ths of an atmosphere.

>It's expensive, sucks up loads and loads of power

I think they know that, don't you? There's no line-by-line breakdown, but the paper allocates $260 million for the station+pumps and 21 MW for electricity consumption (pumping, accelerating pods, and charging pod batteries).

>needs lots of thermal management

I agree that you need it, but what specific problem do you see?

>Pipes are pressurized from the inside. See my comment from elsewhere in the thread on why vacuums are different [2].

You said a soda can is stronger when pressurized from the inside. That's true, but the obvious solution is to make it thicker than a soda can. :) The paper calls for 0.8-1.0 inch thick steel, which my math says is more than adequate.

> I think they know that, don't you?

Who's they? Hyperloop One? No--they've just punted the "hard" stuff to the end. (Kind of like the Wright Brothers designing the seats of their plane before getting it flying. Oh look! [1])

Elon Musk? Yes--I do. That's why he's waiting.

> what specific problem do you see?

The top heats up and the bottom doesn't.

> The paper calls for 0.8-1.0 inch thick steel, which my math says is more than adequate

Adding mass adds strength while increasing the time the structure takes to reach thermal equilibrium. The thermal gradient isn't itself a problem. But if you look at the forces necessary for the materials in question to tear themselves apart, and then consider their thermal coefficients of linear thermal expansion, you can derive a maximum tolerable thermal gradient given the size of each tube segment (we'll assume the problem of reticulating vacuum seals is solved).

When you solve for strength, you get too much material for the system to reach equilibrium before inclement weather either causes (a) the structure to buckle, laterally or (b) the outside of the tube to start shearing itself from the cooler inside.

When you solve for thermal stresses, you lose your strength. Microbuckling and microfracturing may not seem like a big deal, but it is when you're talking about 1 standard atmosphere bearing down from the outside with a capsule swinging about on the inside.

We need a strong material that either (a) conducts heat really well or (b) doesn't change shape when asymmetrically heated. We don't have something that meets those requirements yet that we can manufacture at scale.

[1] http://www.stacksmag.net/2013/10/space-virgin-galactics-rich...

>No--they've just punted the "hard" stuff to the end.

Citation needed. The link provided gives no support.

I would be interested in seeing your calculations on the thermal side. An ANSYS multiphysics simulation (the software SpaceX uses) would show the problem, no?

SpaceX has already built and used a mile-long, 11' diameter vacuum tube in Southern California, which would seem to put this matter to rest (the proof is in the pudding, after all).

> An ANSYS multiphysics simulation (the software SpaceX uses) would show the problem, no?

Yes. But SpaceX != Hyperloop One.

> SpaceX has already built and used a mile-long, 11' diameter vacuum tube in Southern California, which would seem to put this matter to rest (the proof is in the pudding, after all)

I'll go ahead and predict that the strength of that tube will have materially decreased after 1 year in the elements. I'll even posit that will occur independent of rusting, which appears to have unfortunately taken place, due to the formation of microfractures within the metal due to repeated lateral thermal flexing. That said, this was a demo track. It wasn't designed to withstand one standard atmosphere while whizzing fast, heavy capsules inside it for years on end.

>I'll go ahead and predict that the strength of that tube will have materially decreased after 1 year in the elements.

With steel, the real question is not the weakening from Year 0 -> Year 1, but from Year 4 -> Year 5. After an initial period of weakening the strength of steel levels off.[1]

Anyways, another user pointed out that a cheap foam layer can reduce the daily flexing to arbitrarily low amounts, and give an arbitrarily amount of time for the tube temperature to equalize circumferentially.[2] Cheaper than either a temperature equalizing water jacket or an underground tunnel. I know you disagree in that other thread, but I now consider this problem solved.

[1] https://en.wikipedia.org/wiki/Fatigue_limit

[2] https://news.ycombinator.com/item?id=15460535

Axial compressors aren't the only compressor design. Rotary vane compressors have no problem with those pressures.

The internal pressure was chosen explicitly because it was easy to maintain with simple, single stage mechanical vacuum pumps (see Figure 13 on page 22). Heck, the first result on Amazon for "vacuum pump" goes down to 5 Pa. https://www.amazon.com/dp/B012CFTYX4/

Compare the Hyperloop to true "vacuum train" designs, which need to run at 1/1,000,000th of an atmosphere to mitigate sonic booms (an alternate way to get around the Kantrowitz limit). This requires multi-stage pumping with mechanical roughing, followed by turbomolecular pumps and cryopumping. That 1000x harder vacuum takes 1000x as much pumping power (not because the differential pressure is meaningfully different, but because you expel 1000x less air per stroke).

> The Hyperloop’s thermal issues are a hard enough problem that they alone put this in the domain of materials science. That’s the same category of problems separating us from a space elevator.

What? What are you even talking about?? That's a completely ridiculous statement. The pressure inside and outside the lunar landing module was 1,000,000,000,000,000x. 100 kPa to 10^-10 Pa. It makes zero sense to apply this kind of ridiculous relative measurement to pressures because it has no relation to how pressure works. The structural challenge in building a tube that works to .001 atmospheres is only 25% harder than building a tube that works to .2 atmospheres (same as an airplane). And it isn't any more dangerous.

The only challenge that occurs is sealing in that atmosphere without any leaks and that part isn't hard either. 100 Pa is achievable by a $50 pump.

I also have yet to see any compelling argument that there will be thermal issues. Floating mounts and expansion joints are hardly untested technology.

> The pressure inside and outside the lunar landing module was 1,000,000,000,000,000x. 100 kPa to 10^-10 Pa

We didn't pump air into the lunar module from the Moon. We carried it from Earth pre-pressurized. Unless you're proposing we build and seal the Hyperloop tubes in space before bringing them down, the analogy isn't appropriate.

Also, consider a soda can. It's stronger when pressurized from the inside. Modern nuclear attack submarines collapse around 730m [1]. Since for "every 33 feet (10.06 meters) you go down, the pressure increases by 14.5 psi," we're talking about water pressure of about 1,000 psi or about 72 atm.

[1] https://en.wikipedia.org/wiki/Submarine_depth_ratings

[2] https://oceanservice.noaa.gov/facts/pressure.html

The force exerted by the atmosphere on an evacuated tube is the same as the force exerted on a standard-atmosphere filled submarine diving 10m beneath the surface. A 100kPa difference.

And since they explicitly do not want a high vacuum - some residual air inside the tube is necessary for the hyperloop concept! - they don't have to deal with advanced tech like turbomolecular pumps. Simple displacement pumps will do.

Note that downthread, they've already moved the goalpost from "these pumps are technologically impossible" to "but they'll need a lot of them!"

https://news.ycombinator.com/item?id=15459820

> Note that downthread they've already moved the goalpost from "these pumps are technologically impossible" to "but they'll need a lot of them!"

I never said vacuum pumps are "technologically impossible". My original comment references the Space Power Facility [1] and categorises the vacuum problem as an engineering problem. A hard one, but engineering nonetheless.

The comment you link to [2] replies to someone claiming the original white paper calls for a 22:1 atmosphere:tube pressure ratio. I pointed out that the figure they're referencing, Figure 11, discusses the capsule and not the tube.

I'm skeptical about the economics of de-pressurising the tube, but that's an engineering problem and I've always held it as such. The materials problem is the thermal expansion of the top of the tube relative to the bottom.

[1] https://en.m.wikipedia.org/wiki/Space_Power_Facility

[2] https://news.ycombinator.com/item?id=15459820

> The materials problem is the thermal expansion of the top of the tube relative to the bottom.

What exactly is the problem here? Is it because the top of the tube is exposed to direct sunlight? I thought it was supposed to be covered in solar panels anyway. Is it still a materials science problem if the tubes are shaded, because providing a structure that shades something with expansion from direct sunlight exposure seems quite a bit easier than to do so while trying to keep vacuum to a particular level.

>The comment you link to [2] replies to someone claiming the original white paper calls for a 22:1 atmosphere:tube pressure ratio. I pointed out that the figure they're referencing, Figure 11, discusses the capsule and not the tube.

I happen to be that someone. :) You were talking about state-of-the-art axial compressors (the GEnx-2B67), so I assumed you were talking about the axial compressor on the front of the pod. Mea culpa. But then you drew an analogy to the pressures in the SPS ("To get a sense of the engineering differences between 6:1 and 1,000:1..."), as if the Hyperloop people were trying to make a 1000:1 axial compressor. As I pointed out in my reply,[1] rotary vane compressors can easily maintain those pressures.

>The materials problem is the thermal expansion of the top of the tube relative to the bottom.

If that were really a problem, no pipelines of any kind could be built. Again thermal expansion joints are the solution, since with the abandonment of air-ski levitation the pod walls no longer have a requirement to be ultra-smooth. Tiny leakage on these joints is fine, since it will be made up for by the pumps located along the track.

[1] https://news.ycombinator.com/item?id=15460061

> If that were really a problem, no pipelines of any kind could be built

The Trans-Alaska Pipeline system, which I believe is the largest at least in the United States, is 1.2m in diameter [1]. We're talking about a pipe almost 3 times wider that needs to hold itself against the atmosphere and keep capsules neatly contained.

Side note: long pipelines zig-zag to allow for thermal expansion and contraction [2]. You can't do that with the Hyperloop. (Bridges handle this with various ingenious methods, most of which will work for the Hyperloop's longitudinal expansion.)

> thermal expansion joints are the solution

Scaling pipe expansion joints where they maintain the near vacuum and deal with the structural stress of a capsule whizzing by will be difficult. By "difficult" I mean these are problems NASA (for the ISS) and Schlumberger (for pipes) have been grappling with for years and with billions of dollars in R&D.

[1] https://en.wikipedia.org/wiki/Trans-Alaska_Pipeline_System#/...

[2] https://www.quora.com/Why-do-oil-pipelines-that-transfer-oil...

>Unless you're proposing we build and seal the Hyperloop tubes in space before bringing them down, the analogy isn't appropriate.

I am not sure what your objection is here. Are you saying vacuum chambers can't be built on Earth? There are quite a few examples of large vacuum chambers, like the NASA Space Power Facility (23,400 m^3) or the Large Hadron Collider (9,000 m^3) https://scap.hq.nasa.gov/docs/Glenn_SpacePower.pdf https://lhc-machine-outreach.web.cern.ch/lhc-machine-outreac...

Both are pumped down to very high vacuum, not required for the Musk Hyperloop, (low pressure electric jet in a tube) but probably needed for the Hyperloop One. (maglev vactrain) And, obviously, both chambers were built terrestrially, and evacuated using conventional vacuum pumps.

> I am not sure what your objection is here. Are you saying vacuum chambers can't be built on Earth?

No, I specifically linked to the Space Power Facility in my original comment! The "materials science" problem I call out is in the tube's lateral thermal expansion.

The best solution I've come up with for that is to take a regenerative rocket engine [1] and make it a tube. Pumping fluid in spirals along kilometers of a vacuum tube isn't easy, but it isn't as hard as trying to invent a material that won't deform when the top gets hotter than the bottom, or the east side gets hotter than the west.

[1] https://en.wikipedia.org/wiki/Regenerative_cooling_(rocket)

How about wrapping the tube in insulating foam and using peltier modules to regulate temperature. Or even using double walled tubes. It would not be challenging to regulate the temperature, but nobody talks about it because it doesn't even seem necessary.

> How about wrapping the tube in insulating foam

At that point why not just bury it? It swaps the thermal problem for the water problem, but we know how to build tunnels.

>At that point why not just bury it?

Because foam is cheaper? A nice K.I.S.S. solution.

Having seemingly solved this thermal expansion problem "in the same category of problems separating us from a space elevator," I'll be expecting The Fountains of Paradise to come true soon. ;)

> We seem to have solved this thermal expansion problem

I guess I'll have to telegraph my buddies in Hawthorne and at NASA :).

Joking aside, no, foam doesn't solve the problem. You'll still have flexing. This is one of the limits on how long you can have a launch tank on the pad. Imperceptibly small flexing, but of the kind that weakens every metal we know.

>Joking aside, no, foam doesn't solve the problem. You'll still have flexing.

Of course the flexing isn't zero, but by adjusting the thickness of the foam you can drive the diurnal/solar heating thermal gradient arbitrarily low without compromising strength by making the steel walls thinner. That was your material science objection,[1] right?

>but of the kind that weakens every metal we know.

That's true, but misleading. It's true that every metal gets weaker, but in steel and titanium this weakening levels off (all other metals continue to get weaker until failure). Once these two metals are at the fatigue limit they stop weakening and have unlimited flexing cycles.[2] So you can set that as your final material strength and size the tube thickness accordingly.

So repeated flexing is fine, and flexing can be made arbitrarily small with insulation. Foam solves the problem.

[1] https://news.ycombinator.com/item?id=15460617

[2] https://en.wikipedia.org/wiki/Fatigue_limit

> Imperceptibly small flexing, but of the kind that weakens every metal we know.

This isn't a rocket. The tube wall is inch thick steel. It would rust into nothingness centuries before it would crack from distortion.

>The "materials science" problem I call out is in the tube's lateral thermal expansion.

I admire your method of argumentation.

The comment I replied to said nothing at all about thermal expansion. Your original comment, which I wasn't replying to, was mostly strange references to pressure ratios, and a single line about thermal problems, with no numbers cited. In that comment you did link to the Space Power Facility... as an argument against Hyperloop One! You did something similar downthread: https://news.ycombinator.com/item?id=15459777 But by asserting that you addressed the problem in your original comment, you make the person you're arguing with look like a bully, without having to actually address their points. Very efficient.

>The best solution I've come up with for that is to take a regenerative rocket engine [1] and make it a tube. Pumping fluid in spirals along kilometers of a vacuum tube isn't easy, but it isn't as hard as trying to invent a material that won't deform when the top gets hotter than the bottom, or the east side gets hotter than the west.

Using the phrase "regenerative cooling" in this context is another headscratcher. Regenerative cooling in rocketry is running propellant through channels in the nozzle, then either dumping it overboard, using it to power a gas generator, or burning it in the rocket. It's a great way to get rid of megawatts of heat.

None of these things would be useful for a hyperloop tube? You don't want to run kerosene/liquid oxygen/hydrazine/whatever through a cooling jacket then dump it on the ground, you don't need a gas generator for anything, and there's no way to feed the heated propellant to the actual hyperloop car. And if you could, you wouldn't want to, since if you combusted it in the car it would just dump the exhaust in the tube, killing the vacuum.

Presumably active cooling of a hyperloop tube would use a closed refrigerant cycle, which has little to do with regenerative cooling, besides the idea of cooling channels.

Talking about regenerative cooling in this context isn't wrong, exactly, it just betrays a rather shallow understanding of the problem at hand, as seen in your first comment.

> Regenerative cooling in rocketry is running propellant through channels in the nozzle, then either dumping it overboard, using it to power a gas generator, or burning it in the rocket

"Regenerative cooling" is a rocket term. It came to mind because I used to be an aerospace engineer. There's no requirement in the definition of regenerative cooling for the coolant to be dumped.

> Presumably active cooling of a hyperloop tube would use a closed refrigerant cycle

I don't think one can just presume that. You've already got lots of pumps for pumping air. Given (a) the seal on the tube will be periodically broken (for entry, exit and maintenance) and (b) a safety factor, you'll have more pump capacity than you'll need. Filtering and then compressing atmosphere, running it through a heat exchanger, and then letting it expand through the cooling channels before dumping it doesn't seem obviously worse than having kilometers of refrigerant running around.

> which has little to do with regenerative cooling, besides the idea of cooling channels

See above. Also, I assumed if you did this you'd use it to boost SpaceX's nozzles' economies of scale.

>"Regenerative cooling" is a rocket term. It came to mind because I used to be an aerospace engineer. There's no requirement in the definition of regenerative cooling for the coolant to be dumped.

Regenerative cooling in rocketry uses propellant. Propellant is always dumped overboard, because it's propellant.

Please show me a rocket that uses closed loop cooling of the rocket nozzle.

>Filtering and then compressing atmosphere, running it through a heat exchanger, and then letting it expand through the cooling channels before dumping it doesn't seem obviously worse than having kilometers of refrigerant running around.

My turn to be pedantic about definitions: this sure sounds like closed loop cooling to me! The working fluid is air, you draw it from a big reservoir, (the atmosphere) cool something with it, then return it to the reservoir. (Something you can't do with open-loop regenerative cooling of a rocket nozzle, since the coolant gets burned at the end of the cycle)

However, maintaining the air dryers and replacing the filters sounds like it wouldn't be any cheaper than conventional phase-change cooling, and having to build custom vacuum/compressor pumps for the hyperloop project is going to be more expensive than buying COTS vacuum pumps.

> Please show me a rocket that uses closed loop cooling of the rocket nozzle

The most famous one is the under-development SABRE [1], which includes a closed-loop helium cycle. For cryogenic rockets, closed-loop cooling of the nozzle has been explored [2] to avoid hydrogen embrittlement and oxidation of the nozzle channels, as well as to simplify plumbing.

In any case, we've devolved into arguing semantics.

> My turn to be pedantic about definitions: this sure sounds like closed loop cooling to me!

I was figuring on dumping the air once done versus worrying about a reservoir. That said, I haven't done any math on the benefits of saving the return piping (and reservoir cost and maintenance) versus using something traditional.

> maintaining the air dryers and replacing the filters sounds like it wouldn't be any cheaper than conventional phase-change cooling, and having to build custom vacuum/compressor pumps for the hyperloop project is going to be more expensive than buying COTS vacuum pumps

Fair enough. As you observe, it's a problem I haven't seen a suitable solution to (apart from burying, which trades the thermal problem for, in my view, the better water management problem and the scarier land-use problem.)

[1] https://en.wikipedia.org/wiki/SABRE_(rocket_engine)

[2] https://www.google.com/patents/US3516254?dq=closed+loop+rock...

>The most famous one is the under-development SABRE [1], which includes a closed-loop helium cycle.

From the linked article:

>>The 'hot' helium from the air precooler is recycled by cooling it in a heat exchanger with the liquid hydrogen fuel.

It's open-loop regenerative cooling, with helium as an intermediate coolant. The heat still ends up in the propellant, which gets dumped overboard. Not closed-loop.

That patent also specifies a heat exchanger to the propellant tank.

>I was figuring on dumping the air once done versus worrying about a reservoir.

A poorly telegraphed joke. The atmosphere, here, is the reservoir. I have edited my comment.

>However, maintaining the air dryers and replacing the filters sounds like it wouldn't be any cheaper than conventional phase-change cooling, and having to build custom vacuum/compressor pumps for the hyperloop project is going to be more expensive than buying COTS vacuum pumps.

Just want to point out a facet of such a project that you probably haven't considered. The EPA puts strict requirements on the operators of refrigerant systems, the way they categorize operator class is based on pounds of refrigerant. Thus even though a COTS phase change refrigerant system seems like the obvious choice for Hyperloop One, because of regulatory burden it would almost certainly unfeasible. A refrigeration system big enough to cool a hyperloop would have to have every inch of refrigerant line spray tested every 3 months or an insanely expensive monitoring system.

https://www.arb.ca.gov/cc/rmp/rmpcomply.htm#large

Heat tubes use distilled water as a refrigerant and do not use pumps

> We didn't pump air into the lunar module from the Moon. We carried it from Earth pre-pressurized. Unless you're proposing we build and seal the Hyperloop tubes in space before bringing them down, the analogy isn't appropriate.

It absolutely is appropriate, since the module was emptied and filled each time the astronauts left.

> Modern nuclear attack submarines collapse around 730m. Since for "every 33 feet (10.06 meters) you go down, the pressure increases by 14.5 psi," we're talking about water pressure of about 1,000 psi or about 72 atm.

Yeah- so building a hyperloop is structurally as complicated as building a tube that sits 33 feet under water. Hardly sounds complicated when put like that.

An evacuated tube on earth needs to sustain 1 atm.

The worst thing about the Hyperloop concept is how it takes different smart people with slightly different assumptions about what is being described, how it should work, and how it does work in the fields they are familiar with or experts in and the other fields they are only conversant in, and turns those people into rabid defenders of their own calculations that somehow lose the ability to reassess where mistakes might have been made. I'm not sure how or why this happens, because as far as I know none of this is theoretical science, it's just a matter of applying the principles accurately (which seems to be the sticking point). For example, here's a whole playlist of people arguing over the physics of it, which does devolve into name-calling at points.[1] There appears to be good science involved in the assessments though, but could be said for the most part about both parties. The interesting parts are where people step outside their areas of expertise and their unfamiliarity with the application of the principles causes mistakes.

1: https://www.youtube.com/playlist?list=PLSPi1JFx4_-Gz0Fm0qq2K...

We have oil pipelines stretching thousands of miles that are under far more stress. We can build a low-pressure tunnel that stretches without a problem. Nothing in the hyperloop is impossible - it's just incredibly expensive and unprofitable.

Solve the mass-scale construction and maintenance efficiency problem and we can get all kinds of cool things like hyperloops, space elevators, and fancy megacities.

The engineering has never been a problem, vacuum-tube trains are an idea that's been around for centuries. [1] Removing friction and air resistance is a simple physics problem, and there are already operational maglev [2] trains so putting them in a low-pressure tunnel is not a major revolution.

The real issue is the viability of such a transport because of the cost, complexity, and construction effort involved. We (in the USA) can barely build a high-speed rail line effectively so a Hyperloop competing with existing transportation options doesn't make economic sense currently. Take a look at what happened to the Concorde program for a similar example of great technology that just couldn't survive as a commercial service.

1. https://en.wikipedia.org/wiki/Vactrain

2. https://en.wikipedia.org/wiki/Maglev

EDIT: Yes, the engineering effort is not easy, but the science is pretty straightforward. We're not discovering new physics here...

"The engineering has never been a problem, vacuum-tube trains are an idea that's been around for centuries. [1] Removing friction and air resistance is a simple physics problem"

"simple"

Getting to Mars is a simple delta-v engineering problem. Nuclear fusion is a simple magnetic field engineering problem. Self driving cars are a simple programming problem.

Don't ever change, Hacker News.

Ok, we did get rovers to Mars decades ago so I'm sure you know what I mean here, but you seem to be making my point that it's not worth it.

Simple isn't the same as easy, but an evacuated train tunnel with air or magnetic tracks does not require new science. The physics are well understood and simple. The hard part is evolving the tech to be reliable and cheap so that people will use it and pay for it - but that doesn't seem to be within economic reach, and that's before factoring in construction and upkeep.

>so putting them in a low-pressure tunnel is not a major revolution.

>evacuated train tunnel with air or magnetic tracks does not require new science. The hard part is evolving the tech to be reliable and cheap so that people will use it and pay for it - but that doesn't seem to be within economic reach, and that's before factoring in construction and upkeep.

You seem to be suggesting that a) we could have done this before because the tech has always been there. b) we can't do this now because the tech is not reliable or cheap.

I'm not sure how you can rectify these two arguments since this tech is more reliable and cheaper now than it ever has been.

Yes it's possible to build, but no it's not cheap enough to make money on = not worth building.

We can build lots of fantastic things today but they would cost trillions so clearly are not a good idea. You also missed the ending about construction + maintenance, those will be the real costs and aren't likely to become radically cheaper.

To the generations that traveled the world on boats, constructing flying machines that move faster (and required more tech/maintenance) also probably seemed like an unknown of whether it would be prohibitively expensive or not. I'm grateful that they didn't wait long to explore the possibility, which is what Virgin is doing here.

Maybe I'm communicating poorly here but the tech is not the problem. We don't need to invent anything new, we know how to do it. It does need to get cheaper but the construction and maintenance costs are gigantic and that hasn't changed for any big project over the last century.

Jetliners are complex machines but it's the entire infrastructure of airports and traffic control that actually make it possible, which is only viable because people choose to pay for it. Massive infrastructure does not build or take care of itself, and if it did, that would be a far bigger revolution than just building a train.

I had the same reaction to the comment though I don't think I disagree with you. I think it was referring to engineering as simple rather than just calling the science and even a proof of concept as being relatively simple.

Reducing the amount of steel used in a bridge or a building is part of engineering. The Concorde wasn’t just a failure to understand what level of demand the world economy could support, it was that they didn’t solve the problems necessary to make it viable at scale. In that way it was not a complete product, it was a proof of concept.

Or, another example, it is not market dynamics alone that have changed the economics of what’s feasible with transistors. It is engineering that has made them viable at a massive scale.

In the end it's all the same. New science, tech, or strategies, it all takes investment which requires a return of some sort so it's hard to imagine any business take this on considering the alternatives that already exist (and are continuing to get better). Maybe governments can invest in this for public good but that seems unlikely politically.

For example, nuclear is a great power source and we can definitely invest much more but suddenly solar and wind have beaten the economic curve through constant evolution and are better candidates to explore today.

Thank you. It's always easy till you start doing it.

"We can barely build a high-speed rail line effectively...'

There is no high-speed rail line in the United States. The nearest thing to high-speed rail is the Acela Express, which hits 240kph on 40km of track. But this is weaksauce by modern standards.

And honestly, if you want to solve the USA's environmental problems, 200kph commuter rail would probably be a better investment than HSR or Hyperloops.

Definitely agree that more, better transit would have a much bigger impact.

But I'd say the problem of commuter rail is frequency, coverage station locations, acceleration, level boarding, dwell times etc etc. Given that line speed is dictated by acceleration and dwell times, top speed is really far down the list of priorities.

Also, top speed of commuter rail is already up to 200km/h (e.g. https://en.wikipedia.org/wiki/ALP-45DP).

I guess it's just my own experience in Ontario - the GO transit trains look like they travel at about 110kph or so, and once you figure in their slow acceleration and frequent stops that means they're quite slow. Outside of the worst part of Toronto rush hour (which is notoriously bad) they're actually slower than the comparable coach bus from my area (Hamilton).

The overall average speed is a paltry 50kph.

When the train is slower than the coach bus, why even have a train?

The average speed is governed by acceleration and dwell time - the issue for GO is lack of electrification (which increases acceleration), and lack of level boarding (which decreases dwell time).

50km/h average is actually quite fast. I mean, a radius 50km from downtown is a huge area already. We have to densify inside that radius, not sprawl people further out because the trains are so fast. This means for example we need more stations, so that more developable land is within walking distance of service.

> This means for example we need more stations, so that more developable land is within walking distance of service

That's what lrt and subways are for, not the big commuter GO trains.

That's the crux of what's wrong with commuter rail thinking in North America: "Serving the city is what the subway is for". Your original post, asking for 200km/h commuter rail, is a sign of it.

There's a meaningless separation of modes based on technology, and ascribing attributes to them. In Japan or Europe, the technologies are converging and so are the modes. Any infrastructure will have it's utilization maximized, and may function as what North Americans understand as 'commuter rail', subway' or 'light rail' all at the same time.

The result: more coverage, more service, better integration of services, more overall effectiveness, more ridership, less reliance on driving.

200kmh/h is the generally accepted threshold for high speed rail.

EDIT: from the UIC website:

"In any case, high speed is a combination of a lot of elements which constitute a whole "system": infrastructure (new lines designed for speeds above 250 km/h and in some cases, upgraded existing lines for speeds up to 200 or even 220 km/h),..."

http://uic.org/highspeed#What-is-High-Speed-Rail

>We (in the USA) can barely build a high-speed rail line effectively

We went to the moon. We send car sized rovers to Mars. We certainly can (in the technical sense) build a friggin' train. Its a political problem that keeps us from doing it. So its more like "we won't build high speed rail", and there are plenty of interesting reasons why this is so.

The point is that the mystical sounding Hyperloop might be just what the doctor ordered to shake up the political landscape and get something to budge because ooohh... futuristic! It might just be a brilliant end-run around the current political stalemate. At the most local level it has the potential to turn "nah, I don't want a train running through my back yard" to "oh wow, my community is part of the enlightened future of humanity!"

Sure, it's a combination of political/social/economic factors but "futuristic" doesn't seem to have much impact right now (if it ever really did). NASA's trip to the moon was funded by war motives and we've since had the decline of both the space station and the shuttle programs. It's great to see SpaceX doing new things but there's definitely profits in reducing launch costs (again driven by war and business motives).

What exactly is the Hyperloop going for? Short trips are already served by buses, subways and light-rail. World-wide trips won't be feasible against air travel anytime soon, and will probably require the same security procedures as flying because of the speeds and risks involved, especially if crossing national borders.

So connecting major metros is the potential scenario but airlines have already proven that the vast majority want wifi and food so we can be productive and entertained in transit rather than paying a big premium to save a few hours.

Yes airlines are the first thing that spring to mind when I think of wifi, food, and convenience during travel.

Call me an optimist but it's high time for something new to shake things up. I don't care if it's a magic tube train or just some really nice selfdriving busses.

You're obviously talking about transit for the mainstream in which case it's not perfect but airlines provide the best combination of speed, comfort, and service today. Let's not forget that you're actually flying in the air in an incredible machine.

We already have plenty of cheap bus drivers though so I don't see what self-driving buses will do...

Boeing has failed to build an hypersonic aircraft and as a result has done a lot of legislative lobbying to ban Concorde. Despite the petrol crisis and these annoyances, Concorde was still slightly profitable until the end of its life: https://www.quora.com/Why-was-the-Concorde-retired-in-2003-d...

Despite the fact there are more billionaires than ever, it's funny how small the group of bold innovators are. It always seems to be the same few people.

No, it’s different people doing it, but the same few people funding it. Like VC.

I'd argue that Bill Gate's work has a better return of investment for society.

IMO, we need both types - Gates' work improves society in our current world, while Musk and Branson's investment kickstart the scientific and technological advances needed to further our civilization.

When does Hyperloop One get a go on the Dubai - Abu Dhabi line?[1] That's quite feasible. Straight route across flat, open desert.

Hyperloop One is a maglev vactrain. It doesn't "fly" aerodynamically, like Musk's original plan. This means a more expensive track in the tube, but higher riding height. Musk's original plan required a ride height of 0.3mm to 1.3mm, which means a really smooth tube. Maglev clearances are typically 1-2 cm, which is much easier to maintain over many kilometers of tube. Also, only the track has to be flat; the tube can have seams and expansion joints, so it can be fabricated by standard piping techniques. Vehicles can draw power from the track; Musk's original design was battery powered. Maglev track is expensive, though. That's why maglevs are rare.

If somebody in Dubai has the money, there's no reason it shouldn't work. Japan already has 42km of maglev running, part of the Tokyo-Osaka maglev route under construction, with full-sized trains. That's mostly in tubular tunnels. Hyperloop One is easier than that.

Hyperloop One's test track uses a 3.4 meter tube, instead of Musk's original 2.4m tube. Maybe larger in the production version. Musk's very optimistic cost proposals are based on his undersized tube. Hyperloop One will work, but it may not be all that cheap.

[1] https://www.youtube.com/watch?v=3fu-6IDp3Fo

I see so many negative comments about this, but in my opinion everything has to start somewhere. It doesn't matter how crazy and impossible it looks, it will be done eventually (and we have plenty of examples).

Maybe we will not teleport in 2 seconds across the globe or this project will die, who knows if we don't try.

A little bit of optimism doesn't hurt. Just saying.

And for Virgin, it's not my money, if they want to invest in a black hole sure they can.

Right. Could you imagine what people thought/said around the advent of commercial airliners or heck, even automobiles?

Or turbojet trains[1]

[1] https://en.wikipedia.org/wiki/Turbojet_train

Or Ekranoplans[2]

[2] https://en.wikipedia.org/wiki/Ekranoplan

or flying cars, or jetpacks, or a million other ideas that just had "engineering problems" that were supposed to revolutionize transportation.

My favorite historical example of this is that of the nautical screw.

Orwell mentions it in one of his lesser-known essays when discussing the problems with arguing about economics(1).

>"When the nautical screw was first invented, there was a controversy that lasted for years as to whether screw-steamers or paddle-steamers were better. The paddle-steamers, like all obsolete things, had their champions. Finally, however, a distinguished admiral tied a screw-steamer and a paddle-steamer of equal horsepower stern to stern and set their engines running. That settled the question once and for all. And it was something similar that happened on the fields of Norway and of Flanders [referencing economic questions]."

1 - www.orwell.ru/library/essays/lion/english/e_saw

Totally with you.

I'm not saying it can't work and we shouldn't try our best.

However from what I have seen so far I am quite disappointed as even known issues aren't addressed at all. As if the people involved are blindly going at it instead of working with people who know something about pressure vessels etc.

Sure sometimes you need an outside perspective but not like this.

Care to elaborate?

Thunderf00t has a good video on the problems with it.

https://www.youtube.com/watch?v=RNFesa01llk

He has some other good videos (solar roadways) but tends to spend to much time bashing creationists.

Thanks for the video reccomendation, super interesting.

So much this. Especially when people chime in with some minor detail means it will fail because clearly 'must not have thought of it' if they didnt mention in some 400 word press release.

Its like Elon going into trucking and people saying the range isn't sufficient. The guy is pretty darn smart. I'm confident he understands trucking range and has some solutions, and simply isn't discussing it for secrecy and/or succinctness.

Yeah but in this case every solution appears to be turning it into a normal train so we aren't even getting anything novel out of it anymore.

> if they didnt mention in some 400 word press release.

There's a lot of in depth criticism of hyperloop based on Elon's 57 page paper. It is hardly a case of gut reactions to 400 word press releases.

It's been said before elsewhere, but HN is the place to go to find out why your project will never succeed. I've seen many successful projects crapped all over here when they were in their infancy / pre-success days. "Stripe?! 3% fees! So dumb. We already have lots of payment gateways. It's not hard. You just have to {list of many tedious manual steps}..."

My favorite is Dropbox. "Store all my personal and/or corporate files on some third-party server?! DOA."

I remember that thread. Hilarious.

One of my favorites is on Slashdot. If you go there and search for 'VMware' then you can find it.

When VMware was first announced and demoed, the commenters at Slashdot declared things like it was fake, it was stupid, it was a waste, it would never work, or that dual booting was a better solution. They largely concluded that virtual machines weren't a thing and happily congratulated themselves for their brilliant insights.

I'm on a tablet or I'd dig the link out for you. It's one of my favorite discussion threads on the Internet.

Thanks, I really need to check that one out.

I never tell people that they 'need' to do something, so I'll say I highly suggest you do.

So, to make it easier for you - I've grabbed a laptop and dug out the link:

https://tech.slashdot.org/story/99/02/11/0939233/multiple-os...

I absolutely encourage anyone/everyone to read the linked comments. It's one of my favorite examples when a number of discussions come up.

My preferred time to reference it is when people say things like, "Slashdot used to be so much better!" Or when they say things like, "We had much better commentary back in the day!"

No, no they did not. In fact, it was never as good as people recall it being. That is kind of what makes it so wonderful and why I love discussion sites.

I am, by no means, innocent or superior. ;-)

Reminds me, Im just as guilty. Check out my insights on Amazon introducing the Kindle: https://news.ycombinator.com/item?id=81804

Yeah, we've all got comments from our past that we wish we'd not made. Our seemingly brilliant insights aren't so brilliant after all.

Today's thread about Musk's "Hyperloop" is good fodder to bookmark and look back at in a decade. I have to wonder how many of the posters will admit they were wrong, should this reach fruition?

I dug the link out for another person who replied. You may want to take a look?

https://tech.slashdot.org/story/99/02/11/0939233/multiple-os...

There was a database glitch that messed up usernames (I think that was after they'd added accounts, my memory isn't that good so I'm not certain) but it's still an amusing read. It really is a good example for a variety of discussions. It's my favorite example, actually.

Thanks for that, belly laughing. One common thread of these "brilliant" dismissals, mine included, is that they undervalue how much people don't like going through technical hurdles with products and how much they will pay to avoid them and get on with what they want to do. Also, for ambitious goals like hyperloop, many assume technical challenges are insurmountable.

Yeah, there's at least one comment in there to fit most stereotypes. They range from disbelief to saying the product is no different than other products. There are price complaints to comments that don't seem to even understand - but the commenter was happy to add their opinion.

A few people actually understood and made comments, and some had seen a recent demo. Some speculated about patents and one was happy to point out that they had a whole notebook full of ideas. Some seemed to think the software could do things it couldn't actually do, and certainly not at that stage.

One person even complained that it wouldn't work for him because if his old hardware. Others complained that it didn't meet their needs. Some even seemed unhappy that it wasn't available to run on their obscure OS. Of course, they couldn't use a more popular OS and then virtualized their obscure OS.

Also, there are comments to complain about the site management, people insulting other people, and comments that hadn't a damned thing to do with the subject at hand.

For so few comments, it's like they managed to hit every stereotype. It's absolutely my favorite reference thread and it works for so many conversations. I actually made it a point to finally bookmark it on my tablet as I've been using it more than a laptop lately.

More like "uh, how is this different from rsync?"

"Pfff I could just set up my own FTP server and mount it with curlftpfs on my machine. I don't see what's new"

No, now it’s “why do they need 1500 employees for file syncing?!”

https://news.ycombinator.com/item?id=8863

> For a Linux user, you can already build such a system yourself quite trivially by getting an FTP account, mounting it locally with curlftpfs, and then using SVN or CVS on the mounted filesystem. From Windows or Mac, this FTP account could be accessed through built-in software.

This sounds like such an insane proposition relative to the Dropbox we know today.

The top comment is being pedantic that it doesn’t technically replace a USB drive because you have to install software and have access to the Internet. Hilarious in retrospect.

If the biggest complaint someone can have is “you have to have Internet” you’re doing OK.

> This sounds like such an insane proposition relative to the Dropbox we know today.

Does it? If you used WebDAV then you can mount a share in Windows or Linux even over the Internet, and windows at least is good at caching it while you're offline for short periods. For someone who has their own always-on Apache it seems like this would replicate most of the use cases for Dropbox. I think the point that's being missed is simply that most people would rather see a few ads or pay a small fee than administer their own Apache, not that what Dropbox offers is technically so far ahead.

> For someone who has their own always-on Apache

I’m just guessing on numbers, but that probably describes <1% of the population. Most people think Apache is a word used only to describe helicopters.

Absolutely, and that's why Dropbox is successful. But I don't think the part you quoted is wrong as such; the typical HN user really could put together a few components and get something that does most of what Dropbox does.

A small point really, but I'm not sure most people would only think it describes helicopters. I am guessing most people would think it is a tribe of Native Americans.

I admit that it's just a guess, but it does seem likely.

Again, not a major point.

There's also been plenty of valid criticism here as well...

"Hacker News hated Dropbox so..." Is a fun trope, but Dropbox still isn't profitable ;)

In seriousness I bet a lot of us go though the thought process that we want to give constructive criticism, since positive feedback isn't super actionable.

Feeling smarter than the rich people is always a good feeling too (and cheap, since we aren't even betting our own money )

Stripe is an amazing enterprise, but we've yet to see whether or not it will delivery steady profits, and profits anywhere close to the 20 PE that stocks trade at.

Your types of comment annoy me more than harsh criticism frankly, at least criticism can be constructive, your comment is just fluff.

I mean, let's apply your logic to its logical conclusion: we should never criticize anything, ever, on the off chance it could end up working and then people would look back on our comments and call us silly. On that note I'm just starting a gofundme to create my own interplanetary travel agency, don't forget to donate.

Yeah, HN was wrong about dropbox (although some of the criticism was a lot more specific and arguably accurate than some make it up to be). Now let's fetch the comment threads about color.com, about google plus, about the ubuntu phone, about whatever other failed product we've already long forgotten about.

If HN is wrong about hyperloop, so what? You'll be able to gloat about it in a few decades from your supersonic train seat. In the meantime there are real, practical questions that need answering and that's a much more interesting discussion than "wow this is so coool" or "I wonder what Elon Musk's armpits taste like".

Do you think that the Hyperloop One folks are going to read this thread and give up on the project? "Well, looks like we were wrong, shut down everything folks". I can get this argument for a small startup of one or two young entrepreneurs but for some reason I don't expect Virgin Group to be that insecure.

I only wish that HN was similarly skeptical about near-term Mars colonization. For a group of largely smart, educated people, too many are willing to suspend disbelief for a sufficiently charismatic person, or out of desperation.

Strawman

My instinct tells me negative comments aren't actually coming from the direction of "stupid idea! can't be done!". This isn't to say there aren't significant engineering roadblocks to the Hyperloop, but I don't think that's the root of the negativity.

People are pointing out the glaring flaws in the Hyperloop idea, not because they can't or won't believe that crazy ideas are possible, but in reaction to the media's reaction to Elon Musk's PR. Surely I'm not the only one who wants to upchuck every time that Musk makes a claim and the media drools all over whatever he says. It even goes beyond the media itself but how the public reacts to how the media reports Musk. Otherwise smart people I've met have likened Musk to a modern day Edison, or even Tesla. Musk's companies have achieved great things, but he has more in common with Barnum than famous inventors.

Testing impossible ideas is wonderful. Musk's PR being inflated by the media, creating an audience of believer sycophants, is a different story and I really don't mind people blowing holes in the Hyperloop theory if the newsprint-spewing public isn't going to get that from technology reporters. I'd bet Hyperloop critics actually like the idea at one level or another, and hate to see such ideas looked at with pollyanna eyes.

He operates the first-ever successful private spaceflight company. (You can quibble with this but it's something close to the truth). Likening him to Barnum is a little insulting.

That's not something I would contest, and I don't think I implied such a position. I(and presumably others) actually like impossible ideas but dislike the rampant lack of skepticism in the direction of Musk, therefore criticism of his company's proposals is justified and not necessarily coming from the direction of "it can never work".

Likening him to Barnum would perhaps paint him as a little more nefarious than Musk actually is, but I wouldn't consider that insulting. The man was a master promoter. But perhaps he's not a good analogue because their "products" are very different. People liken Musk to Edison, and they did both own technology companies that produced innovations, but that's where the similarity ends.

Let's be honest. People criticize because it's easy, makes them feel good, and because they have no skin in the game.

You might like the idea that it's some sort of reasoned rejection of Elon PR, but it's not. Just make a Show HN sometime.

> It doesn't matter how crazy and impossible it looks, it will be done eventually (and we have plenty of examples).

Or it won't. Most companies fail, I expect most ideas do too.

> A little bit of optimism doesn't hurt. Just saying.

Yes and no. Optimism is worthwhile but realism is important too. It's cool that private companies are pursuing these ideas and I wish them all the best, but when I see people claiming that e.g. California's high speed rail is overpriced/pointless because of hyperloop then I want to scream. We shouldn't let our enthusiasm over these hyped ideas detract from implementing the more pedestrian approaches that are proven to work and address our very immediate needs.

Hope it fares better than Virgin Galactic which is at least eight years behind schedule (first commercial flights proposed for 2010).

Didn't Virgin Galactic go on hiatus after the test pilot died?

....Are they going to rename it in the future based on the number of pods that have gone through its tubes?

I see they are using the term "extremely low pressure tubes" instead of vacuum tubes.

I know there are feasibility questions, but have you thought about how such travel could affect the course of U.S. politics?

One could feasibly live in Utah where land is cheaper, but still commute to California for work. This would both lead to a purpling of many red states, as well a providing a path for interior state natives to find good jobs in coastal city centers.

Knowing the status of American politics where highly populated coastal states are overpowered in the Senate by the seats of the near empty states in the interior, one can see that if the potential for hyperloops is realized, there will could very well be a massive shift of power back to the populace with more equally distributed representation.

Keeping a plain miles-long tube at at least 90% vacuum seems pretty hard to me, especially when needing to deal with evacuations and possible breakages. Why not divide the tubes into discrete sections gated by movable airtight caps that side away while passing through? If one section repressurizes due to evacuation or some other fault, so be it.

If you have a breakage or stopped capsule you anyway have to shut the whole thing down.

I could see investors wanting to fund this simply for the PR benefits; whether or not such a system is actually viable.

Or, perhaps they'll spin a few technologies out of it.

Or, perhaps they want to grow a network of related companies+technologies that they can re-purpose to another venture in the future.

Lots of comments about how this is not feasible, but wasn't spaceX's vision of a reusable rockets similarly not feasible at the outset and they've since been making some quite considerable progress towards this.

HN certainly did _not_ take a "not feasable" stance on spaceX's vision of a reusable rockets.

A reusable rocket was not just feasible, it had already been done with the Space Shuttle. "We'll do what the Space Shuttle did but 50x cheaper" is ambitious to be sure, but it's not at the same level as "we'll do this completely new thing that has never been done before".

I wonder if the tube could be continuously woven from carbon fiber and given an aerogel insulating wrap, then the interior coated with ceramic? This would perhaps mitigate heat expansion issues.

I bet with Hyperloop One becoming `Virgin Hyperloop One`, the hospitality and the customer care experience will surely be awesome, thanks to the Virgin Group :D :D

Imagine if half of these commenters were around when the Wright brothers were pioneering aviation?

This kind of skepticism would have been perfectly acceptable had the Wright Brothers wrote three pages of guesswork and napkin math instead of actually building a plane.

> instead of actually building a plane

https://www.youtube.com/watch?v=jjv7bB9hy0k

I have no doubt that there was just as skepticism about the invention of aviation.

I’ve been curious for a while if hyperloop and boring company are complimenting each other.

Didn't expect to see Dick putting his name on this one...

I guess one of the silver linings of living in a "cyberpunk neo-Gilded Age but with better UX than '80s cyberpunk" world is that dueling tech magnates might accidentally craft something that could help society.

Anyone else see Branson on Shark Tank the other night?

Great youtube video that presents huge barriers to the hyperloop:

https://www.youtube.com/watch?v=RNFesa01llk

I feel that name has got to be a double entendre.

Seeing as it'll be the first hyperloop? Or are you talking about the maiden voyage?

VH1 rises again.

How safe would the hyperloop be from tube implosion?

https://www.youtube.com/watch?v=T9bpUfWy8Wg

I guess it would depend on how well they engineer the whole system, but who's going to watch over the hyperloop building companies to do that right?

I wonder where this company would be if the original paper was written by pretty much anyone other than Musk.

Everybody talks about the engineering challenges, which have been beaten to death. Elon Musk has a pretty respectable track record of making things that seem technologically infeasible and making them happen. He's not in charge anymore, but I trust that he wouldn't put his name on something that's not possible. Even if it wasn't possible, I'm not the person to make that critique.

The bigger challenge, IMO, is economic. High speed trains make a lot of money, but their revenue has little to do with competing with airlines over significant distances between large cities, which is what the Hyperloop is attempting to supersede. The financial success of high speed trains has much more to do with their ability to rapidly start and stop in lots of intermediate urban areas within a corridor. I know this goes against the popular narrative about why high speed trains are popular (OMG they can compete with air travel!!!), but the narrative is wrong.

The revenue of HSR has a lot more to do with the number of cities that it services than the end to end speed. If you look at ticket revenues on successful HSR lines, terminus to terminus tickets typically make up <15% of total revenues. The rest is made up by the remaining cartesian set of city pairs. Even if you could add up all possible market share (trains, planes, cars) between terminus cities, it would still be less than the total revenue for that line, due to the additional cities it serves. Even with the gradual growth in power levels for high speed trains, with some now capable of 360kph, end to end speeds have basically gone unchanged. What has changed with more powerful trains? The lines have more stops now...they serve more cities, with the higher power levels used for faster acceleration and deceleration. More cities means more revenue, whereas higher speeds have already hit strongly diminished returns.

Maybe with Hyperloop being really fast could grow the market and monopolize market share between Alpha cities, but that would still be a stretch if the goal is economic viability. People see hyperloop, they crave its speed, but the costs are too high and revenues are too low to just serve the endpoints. But if you decide to serve intermediate cities, you slow it down, and it no longer becomes the object of technological lust, and nobody will want anything to do with it.

Among economic historians and really nerdy train enthusiasts like me, this isn't a contentious point. The same economic delusions were a primary causative factor in the overhyping of railways during railway mania, best exemplified in chapters 16-20 of Collective Hallucinations and Inefficient Markets: The British Railway Mania of the 1840s [0], which is a masterpiece of economic history IMO. Anybody in charge of building out some version of hyperloop should do themselves a favor and read it, and then work on not repeating history.

[0] http://www.dtc.umn.edu/~odlyzko/doc/hallucinations.pdf

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