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Comment by 18172821 | Hacker News Reader

I've never been able to find an actual technical description of the hype-loop.

Wasn't it downgraded to maglev at some point?

The original air-supported Hyperloop concept, with clearances of a few millimeters between vehicle and tube, isn't looking good. The MIT prototype uses maglev suspension and more clearance, which is safer.

Maglev in vacuum or near-vacuum is not a new idea; it's been discussed for decades. The question was always whether the vacuum tube was worth the trouble. The Shanghai airport maglev reaches 250 MPH right now in normal operation, and air resistance isn't the limiting factor on speed. The Japanese L0 Shinkansen reaches 375 MPH in tests, with an operational speed of 315 MPH. The main problem with maglev is that the track costs too much.

The main claim for Hyperloop is that the tube is cheap. The original cost estimates assume using someone else's right of way and unreasonably cheap tunneling. Also, to get the straight right of way, the endpoints have to be somewhere inconvenient, well outside major urban areas.

> the endpoints have to be somewhere inconvenient, well outside major urban areas.

I imagine large urban areas will spring up around wherever a hyperloop endpoint is built. The builder might even be able to subsidize themselves by purchasing large radius of land around the endpoint prior to building it.

I think you underestimate how long it takes to build a sizeable city, big enough to support having a hyperloop station or endpoint.

Depends on the circumstances. Sizeable cities have emerged at a rapid pace before.

https://en.m.wikipedia.org/wiki/Shenzhen

http://www.newgeography.com/content/002862-the-evolving-urba...

Yes, but you can agree that Shenzhen is a little different from a station at the endpoint of a hyperloop. To have a city grow more or less organically it's going to take a lot of time.

It makes more economical sense to build a hyperloop between cities that already exist and can sustain it, than to think the world works like Transport Tycoon Deluxe.

Cities are like organisms, and as such, they only grow in the right "habitat" where conditions are right. Namely sites that are intrinsically important in some way, where there are numerous reasons for a city to be there. Proximity to transportation infrastructure is certainly one of the factors, but if that's all you have, lacking will be any of the others you'd find in a great city (most of which tend to be by-products of its having been there a long time, which usually means, maybe ironically, being near the transportation infrastructure we tend to associate with past centuries i.e. rivers, harbors).

Result: You can't create a truly vibrant city in an arbitrary location. You might be able to manage a bedroom community or suburb though.

An example like Shenzhen from a centrally-planned economy would tend to have limited applicability to the US, but this one is interesting because it's the exception that proves the rule. Shenzhen would've been an "important" place regardless, due to its being the first place in "mainland" China north of Hong Kong. Before 1980, the aforementioned central planning kept it from developing as fast as it probably would have otherwise. When they opened it for foreign investment, it took off like releasing a slingshot, hence the high growth rate.

As I said before, it depends on the circumstances. With regards to what those circumstances are, there are a few different combinations of circumstances that would drive rapid growth in a city, and whilst superior public transportation isn't enough on its own, improving infrastructure across the board can be, especially in an area with a high volume of economic activity. For example, look at the growth of Singapore and consider whether that growth would've been possible without a focus on infrastructure.

https://en.m.wikipedia.org/wiki/Singapore

The concept of a vacuum tube dates back further. You can look up Evacuated Tube Transport (ETT), which is basically the core of the Hyperloop idea.

There was one company that was proposing building an ETT between Chattanooga, TN and Atlanta, GA in the US; reducing the two and a half hour drive to less than twenty minutes. It never really got past the environmental planning phase (plus Chattanooga didn't want Atlanta commuters, because the South and anti-progress).

A successful tube transport system could be technologically ground breaking. Theoretically they'd be faster than airplanes and use a fraction of the fuel/energy (once they're constructed of course; not counting development costs).

But they have all the same design problems of monorails (the worst and least expandable form of public transportation). Difficult to switch lines and difficult to extend. Also you get the additional difficulty of turning, which apparently is very difficult in ETTs.

> But they have all the same design problems of monorails (the worst and least expandable form of public transportation). Difficult to switch lines and difficult to extend. Also you get the additional difficulty of turning, which apparently is very difficult in ETTs.

I see the fan group for monorails has a response on the switches http://www.monorails.org/tMspages/switch.html - what are they missing?

Monorails operate at relatively low speeds. It's much easier to switch something running 20 mph than something at 200 mph, particularly because you start running into issues with the acceleration curves and thus having the two lines angle off appropriately.

> A successful tube transport system could be technologically ground breaking. Theoretically they'd be faster than airplanes and use a fraction of the fuel/energy (once they're constructed of course; not counting development costs).

The track would also be far more expensive to operate and build than high-speed rail in pretty much any aspect of the project, the tolerances that need to be complied with for safety reasons are orders of magnitude smaller than the ones in high-speed rail, and it's impossible to ensure a human-tolerable ride.

It appears that everyone is caught in the romantic vision of the future that the Hyperloop salespeople are dedicated to sell to the public, but rarely are the fundamental problems even mentioned.

There are plenty of good reasons why maglev hasn't caught, and the concept being sold by Hyperloop's sales team is far more limiting and expensive to pull than the maglev concept.

What could be the challenge of maintaining many miles of near vacuum in California, where the ground will never move... /s

Elon Musk wrote a paper on it[0].

[0] http://www.spacex.com/sites/spacex/files/hyperloop_alpha.pdf

Just to add a company took the name and is trying to build something else. https://hyperloop-one.com. There has also been a lot of ideas on these lines. What made the original design different was low vaccume* which is vastly cheaper than high vaccume, and using the fan on front and ground effects to effectivly fly vs maglev or traditional rail.

Note in this context high vaccume is hard, low vaccume is cheap. http://www.npl.co.uk/reference/faqs/what-do-high-vacuum-and-...

The original announcement itselfwas a technical paper.

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