Elon Musk's Hyperloop

It's been a bit of a wait, but Elon Musk has now published a design study for his Hyperloop transport system. There's a 57 page PDF in which he (and others apparently, but there are no authors listed) describes a magnetically accelerated hovercraft that travels inside a very low-pressure (but not vacuum) steel tube at high subsonic speeds, all driven by solar power. It'll get you from LA to SF in 35 minutes, at only 9% of the cost of the recently proposed high-speed train link. Good idea?

(And for all you folks who like to post wild technological dreams on the internet, this is how you do that )

I've emailed Mr.Musk and sent him messages on google+

I think my idea is stage 10 (Zeropto)

this is stage 1

Bureaucrats crack me up... probably didn't even realize how silly he sounded trying to defend his expensive and anemic rail project.

Do you think "The Head of the California High Speed Rail Project" is an elected position? If so, could we convince Elon Musk to run?

He has better things to do. Apparently this is just something Musk thought up and did the study on more or less on his own and the MSM picked it up and gave it the gravitas that only a billionaire gets. Not exactly a new idea. The first subway systems were pneumatic. He's not even proposing it as a business venture like SpaceX or Tesla.

Honestly, I was a bit disappointed. Electric motors (both conventional ones and linear induction motors) and turbines have been around for over a century, hovercraft date back to the first world war, there are thousands of miles of steel tube around in the form of pipelines, and the prior art for concrete pylons dates back to the Romans. It's boring! Of course, that's why it has a chance to actually work.

I don't agree that it's comparable to a pneumatic subway system though, not at those speeds and distances.

Lourens, you have to keep in mind that in our age and time a lot about innovation doesn't relate to inventing completely new things, but about combining existing things to achieve something new.

Internet? A new way to spread information over existing networks.
Smartphones? Combination of things that existed before.
SpaceX? They haven't invented anything radically new (yet), they just did basically the same thing others have done before, but in a new, more efficient way.
Tesla? Electric Cars date back to the 19th century!

Nothing about the hyperloop may be new by itself, but I still think it would be a worthy alternative to todays train systems.

(In Europe, the situation with trains is bad, because even for ~500 miles journeys a plane ticket can be bought for about as much as the train ticket. And even with modern bullet trains, traveling by plane is a lot quicker than by train. As far as I know, the situation is even worse in the US, where trains aren't even a real option in a lot of areas).

Pretty much. US regional or national passenger rail is pathetic, a token shadow of what it once was only kept alive by governmental support. What is worse than the cost is the speeds our old slow trains travel at. Completely untenable at the pace of modern life except to those who have plenty of time.

That is where Hyperloop has a potential to (re)create the passenger "rail" system. However there are lots of entrenched transportation interests that will resist it tooth and nail. Everything from the above mentioned functionaries and politicians to the entire existing planes, trains, and automobiles ecosystem that they are beholden too.

Marcus: why yes, of course. As an engineer I'm very pleased with the fact that it doesn't need any revolutionary new technologies. If you can create revolutionary new capabilities using proven technology, so much the better. But from an entertainment perspective, a revolutionary new technology would have been much more interesting .

I also agree with your examples, with perhaps the exception of the Internet (or rather packet-switched networks in general) which was quite a departure from the circuit-switched networks run by the telcos that we had before.

James: Amen, alas. I'm sick of the 20th century. Let's get the 21st on the way already!

I think it's brilliant. I've read it, and I think it'll work. There are three crucial parts to this proposal:

1. The partial vacuum. This is old news.
2. The compressor in front. It's such a simple idea, and it solves a big problem in an elegant way.
3. The air hockey idea. Makes hyperloop much cheaper than maglev, while keeping friction low.

While there's nothing really revolutionary here and anyone with some engineering and physics knowledge could have dreamt it up, Elon was the one who did it. He also had the resources to refine it and run simulations to bring it closer to reality.

The solar/battery twist is a result of Elon's environment; Tesla Motors, SolarCity and California. If this was to be built in Norway, we'd probably have ditched the solar panels and reduced the number of batteries.

You'd just connect the tube to the outflow pipe of one of your hydro plants .

There's been quite a bit of criticism of the financial side of this plan. Elon doesn't seem to have thought about how to take the thing into the city centres, and if you need another hour on each side to get from downtown to the Hyperloop station then the speed advantage rapidly disappears. If you do put the station downtown, it's going to be a lot more expensive. On the other hand, people seem to be assuming that the high speed rail link is actually going to be delivered at its current budget, which seems questionable to me as well.

There are also some technical issues: how to pressurise the airlocks quickly enough, time needed to board, and I haven't seen a design for a split (point, switch) in the track either. I think the technical issues can be solved though, for example if you turn off your front fan a while before entering the station, air will pile up in front of the vehicle, and if you time it well and slam the door closed behind you, you've got a pressurised airlock right there and a braking system to boot. Time needed to board can be increased by building extra platforms (build up as well as sideways!) and handling the vehicles in parallel. Add some actuators to the side air bearing supports and the vehicle can push itself into the right direction in a split; some way of making that passively safe would be nice though.

Anyone seen any other problems with it?

Any problems? Who is gonna pay for it? It costs even more than elon musk has! Unless you can make money off of it. . .

Well, I know it sounds revolutionary, but perhaps you could sell tickets? You'd need investors to build it of course, and to get those you need a solid business case. But there's plenty of precedent in toll bridges and roads, and alternatively the government could do it, just like with the high-speed rail project. Good infrastructure benefits everyone.

If they're considering building a new railway then they will need to fund that somehow. If they can get more benefit for less money by building Hyperloop then why not?

I don't know what the engineering challenges with the airlock depressurization are going to be. I do think it's just a matter of having enough pumps. Perhaps the interior of the airlock can have a shape that hugs the capsule with very tight clearance, to minimize the volume of air that needs to be pumped out. I'm sure Elon has the basics figured out and the numbers duly crunched :)

Ahhh, good idea! You'd just make the tube more narrow as it approaches the station, no need to turn off the fan and time it just right to brake and pressurise. Or perhaps do both.