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Comment by gene-h | Hacker News Reader

Here's a bit more on the specs of MIT's design: http://hyperloop.mit.edu/

From the lift to drag ratio(14) and cruising speed provided(110 m/s), we can compare it's performance to other forms of transportation(neglecting air drag) using the Von Karmen Gabrielli diagram[0]. Using the inverse of the L/D ratio as the specific tractive power and using the updated Von Karmen Gabrielli diagram in [1], we find that performance is expected to be a bit better than that of a commercial plane.

This is pretty promising. Although power required for stabilization and overcoming air drag should be taken into account.

[0]https://en.wikipedia.org/wiki/Von_K%C3%A1rm%C3%A1n%E2%80%93G... [1]http://www.ingenia.org.uk/Content/ingenia/issues/issue22/Imp...

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But 110 m/s - that's 396 km/h or 246 mph - about the speed of a high speed train in Asia or Europe, give or take. And that is when the pods are empty. Sure, without the friction of the rails and the air you save energy, and maybe you can build the whole thing cheaper, and that's lovely and all.

But wasn't the ambition to go much faster than a train? I thought this was about reaching speeds of airplanes...

If we are at speeds around or below 200 mph when the pods are full, SF - LA would still take a couple of hours. A French wheeled TGV could have done that 35 years ago. A Japanese wheeled Shinkansen could have done that even before. A Japanese or Chinese maglev version of the last 1-2 decades could easily beat that. And that's without being stuck in a dumb tube. By the time the hyperloop becomes a reality, if ever, there will be tens of thousands of miles of high speed rails around the world.

The hyperloop is a sizeable amount of current hype and a future loop with pods that barely match yesterday's high speed trains. These high speed trains, engineering wonders that actually exist, don't receive any attention in press. I'd say that the hyperloop has been remarkably good at sucking the air out of the room.

I don't understand all these comments talking about how these prototypes are inferior to existing transportation technologies. You're comparing something completely new, that's barely started the transition from thought to physical reality, with technology that's half a century old.

The Wright Flyer was slower than a contemporary ship, let alone a train, yet this technology quickly became the fastest transportation available.

Hyperloop is supposed to average about 600MPH and hit a top speed of 760MPH. Now, that's a far-off estimate of something totally unproven and could be way off, but if you're going to compare it to alternatives you need to compare what it will become, not what it currently is. You might disagree on what it could become (I have no idea how much of the supposed specs are feasible and how much is just wishful thinking, and it wouldn't surprise me at all if it couldn't achieve its goals) but you can't just look at some first-try barely-works prototype and assume that's the end state.

People compare it to what's currently available, because if it's not any better there's no reason for customers to use it, which means there's no continued revenue stream to fund developing something better.

The Wright Flyer was far cheaper than the Hyperloop will be to develop, and airplanes had uses beyond just transporting people (namely military, which meant government-subsidized development).

Might as well complain about the lack of seats, then (somebody in this comment thread did!) since no passengers means no revenue for further development.

Your comment makes sense, when applied to the first commercial deployment. Which is years out at best and nobody knows what it would really look like. This stuff right now is not even a prototype, it's barely a proof of concept. Complaining about the specs is on essentially the same level as taking a wind-tunnel model of an airliner and saying that it's not big enough to fit any people.

> A French wheeled TGV could have done that 35 years ago. A Japanese wheeled Shinkansen could have done that even before. A Japanese or Chinese maglev version of the last 1-2 decades could easily beat that.

On very few select tracks – the Shinkansen could drive 500 km/h, but is still limited to 320 because of a lack of suitable high-speed tracks. Same goes for the TGV, and the Germans don't even bother with trains faster than 250 km/h.

Speaking of which, Germany sold their maglev technology to Japan and China in the first place because there was nowhere to put it at all. With Germany's winding railroad network it's impossible to reach speeds high enough to justify maglev.

400 km/h sustained, over tracks longer than 400km, would already be a massive improvement over the status quo.

Assuming, of course, the Hyperloop will be able to build a sufficient rail/tube network.

Assuming, of course, the Hyperloop will be able to build a sufficient rail/tube network.

Given that assumption, existing trains could also sustain something in the vicinity of 400 km/h by your own words.

Germany rebuilt and supplemented some of its railroad network for the ICE, at enormous cost (e.g. Wikipedia says the 250 km from Hannover to Berlin cost around 2.5 billion EUR, not adjusting for inflation). Of course that's nothing compared to rebuilding an entire transit network from scratch. I'm not sure any western country has even attempted to do that post-WW2, I guess China's recent investment into high speed rail is the closest modern example.

Another interesting point of comparison with existing rail networks aside from average speed is efficiency. A well utilised high speed train is more efficient than a car, but it still uses a heck of a lot of energy (with corresponding emissions, somewhere). Given the reductions in drag, I'd assume -- hope -- that a Hyperloop train will use less energy per passenger kilometer than existing trains.

That's the thing: This pod could potentially go 396 km/h given that they are able to lease, buy or expropriate land in a straight enough line allowing them to construct mostly straight tubes miles after miles and given that there are no natural barriers like hills, mountains, rivers etc. that prevent this either. But those same conditions are the main obstacles for traditional trains reaching high speed. It's really hard to find land for straight rails nowadays. Railroads tend to go from city to city, not from one point in an empty desert to the other. So they have to bend and twist and turn or go through tunnels. Most of the efforts on getting higher speed in Europe is about straightening out the rails and laying down modern rails.

Maybe the hyperloop can do sharper turns at high speed, and probably next generation of the pods or the loop allows for higher speed in general. But that the winner of the first attempts promises 396 km/h and not the +1,000 km/h we heard about before, does deflate the whole idea.

You are forgetting that the hyperloop design naturally lends itself towards being placed on separate, comparatively cheap pylons, since the structural rigidity and relatively low weight of the tube sections allows them to be far more self-supporting than maglev tracks or even traditional rail tracks.

This essentially removes the requirement of flat land from the equation.

Also, remember that the hyperloop is really much more geared towards the American need: large cities are separated by much greater distances than Europe, meaning that a faster and cheaper per kilometer solution is needed than high speed rail.

Here is a map showing high speed railway connections in Europe. German ICE trains usually peak at 300 km/h on selected tracks while the French TGV can go up to 320 km/h.

https://en.wikipedia.org/wiki/High-speed_railway_line#/media...

There is a huge project upgrading existing railway tracks throughout Germany to make it possible getting from Berlin to Munich in under 4h by 2017.

http://www.vde8.de/---_site.project..ls_dir._likecms.html

> German ICE trains usually peak at 300 km/h on selected tracks

So selected, in fact, that the DB is currently procuring over 300 ICEs limited to 250 km/h, and a grand total of 17 (with an option of up to two more!) that peak at 320 km/h.

I'll call myself lucky if the train manages 180 km/h on my usual routes.

You dropped the small detail that those new ICEs are going to replace IC and EC trains first. And those usually run below 250 km/h. And only in a later phase they are going to replace ICE 1 and ICE 2 trains, which can only go 280 km/h.. so not a huge downgrade.

They are not a replacement for those trains running fast services (with legs with 300 km/h in them).

Your numbers are a bit wrong, German high speed trains (ICE) go up to 300km/h. That's for scheduled connections, not tests.

There's several types of ICEs, only two manage 300/330 km/h – they make up less than half of the current inventory, and are scheduled to be reduced even further.

Meanwhile, the more ubiquitous current 280 km/h models are scheduled to be replaced with a more economical 250 km/h one – and they won't even reach 200 km/h on most tracks.

Yes, ICE 1 and ICE 2 "only" go 280 km/h, only ICE 3 (403/406/407) can do 330 (320 for the 407).

ICx / ICE 4 are meant to replace the IC/EC trains first (which are slower than ICx) and later ICE 1 and 2. It seems that their slightly lower top speed shouldn't matter because of improved ac-/deceleration and relatively frequent stops (every ~70km). ICE 3 would do the 300km/h bits with longer distances. That seems like a good idea to me.

I'd like to ask on a source for your claim that ICE 3 "are scheduled to be reduced even further." The series 407 trains are just being rolled out.

Also, by definition most tracks will always be slow because there are many local / less-used tracks where such speeds simply don't make sense. Most long-distance tracks are pretty fast, and lots of upgrades are being built or in planning. I find your point misleading.

I'd say that the hyperloop has been remarkably good at sucking the air out of the room.

Could that be a positive feature, though?

It seems that in America, and particularly in CA where they're currently arguing heatedly about light rail, there are interests that have captured the industry - it's impossible to construct and operate these conventional technologies for anything short of insane amounts of money.

Perhaps it's possible to sidestep all the rent-protecting regulations, etc., by making the conversation about a technology whose regulation has not been thoroughly captured.

Well that boondoggle they are building in California isn't light rail. Light rail systems in many cities stifle mass transit effectiveness by sucking all the money out through build out and maintenance that would be better spent on more effective busing and other alternatives.

Hyperloop is a heavy rail competition and the one planned in California is a disaster on many fronts, it is pure political in need and desire and hasn't got a viable economic case.

The only reason I would see to support a hyperloop is that if it is commercial driven and supported. We don't need more of the same, we need a real game changer that shows true potential to replace other long distance forms of transport.

With regards to rail, for all the belly aching about the US not having a large number of people traveling by that means you need to realize that the US by far makes up for this with the freight that moves this way. Also for a much longer time the US had a much cheaper and easier transport by plane than Europe has but even now that is ramped up and continuing to do so.

Rail changes behavior, buses don't. Rail builds cities in a way that bus systems never have. It's not a simple optimization problem.

On the other hand, buses can adapt to changing needs. You can easily add or move stops where the activity warrants. Rail demands that everything else conform to its physical installation.

Adaptability means unreliability: the fact that bus stops represent minimal investment is part of the reason they don't drive changes in behavior.

All of the replies are missing the main point here, which is:

We are not even at the prototype stage. This is still the design stage, and of only a single design to boot. Do not expect 110 m/s to be the maximum speed limit of this technology. We're just barely getting started.

The potential to go much, much faster is still there.

Nonesense - The whole point of this tech is to eliminate air drag?? Initial idea is that some air is left in tubes, because it's easier than creating a complete vacuum and the small amount of air can help lift the pods or train. Longer term less air more vacuum better maglev - allows UNLIMITED speed ie we're talking 20,000 kph + . Energy efficiency vastly improvement since for high speed trains 95 % required to overcome drag. This would of course revolutionise transport - will require a new paradigm of construction and manufacturing based on just using robots and software, I think we're close to a tipping point that will realise this sooner than most expect, probaly within 25 years.

This design requires a rail down the middle of the tube? Am I reading that right?

Yes. Furthermore, there is no air hockey.

The winning design is a maglev.

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