Elon Musk’s Hyperloop: a realistic alternative to high-speed rail?

The Hyperloop Is Not as Crazy as It Seems

The future of how we move.
Aug. 13 2013 5:35 PM

Believe the Hyperloop

Elon Musk’s wild vision of superfast transit is not as crazy as it seems.

Hyperloop passenger capsule version cutaway with	 passengers onboard.
A rendering of what a Hyperloop passenger capsule might look like.

Image courtesy Elon Musk/SpaceX

Two years ago I wrote that high-speed rail was dead in America, but that we shouldn’t mourn it too much, because the technology would soon be obsolete anyway. Since then, most states have in fact ditched their high-speed rail plans for good. The notable exception is California, where Gov. Jerry Brown has pressed on with plans for a 220-mph line from Los Angeles to San Francisco. His determination is admirable. But for a man once known as “Governor Moonbeam,” Brown’s vision today is looking a tad conventional, especially when you consider that China and Japan are already starting to build much faster trains using magnetic levitation. At this point, building California’s $68 billion “bullet train” might only solidify America’s status as a follower rather than a world leader in transportation infrastructure.

Will Oremus Will Oremus

Will Oremus is Slate's senior technology writer. Email him at will.oremus@slate.com or follow him on Twitter.

Hyperloop Alpha
Sketch of a capsule, indicating the air cushion it would create and ride on

Image courtesy Elon Musk/SpaceX

That really irks Elon Musk, the visionary CEO of Tesla and SpaceX. So much so, in fact, that he was moved on Monday to hold a press conference detailing his idea for a radically new form of long-distance people-mover. He calls it the Hyperloop. He claims that it would get people from LA to San Fran in a half hour flat, be entirely solar-powered, and cost less than one-tenth as much as high-speed rail. And if people keep doubting him, he just might prove it.

What’s a Hyperloop? As described in a 57-page paper put together by Musk and some henchmen from Tesla and SpaceX, it’s essentially a long, pneumatic tube through which passenger-carrying pods zip along at 700 mph on a cushion of air. It’s not a vacuum tube, exactly—Musk considered that but concluded it would be unworkable. Rather, the pods are propelled through a very low-pressure tube primarily by means of linear induction motors mounted along the tube. These would “reboost” the pods every 70 miles or so until it was time to slow down, at which point they would go into reverse, recapturing the energy expended in acceleration.* Oh, and the whole thing would be powered by the sun, with panels on top of the tube generating more than enough energy to run the system.

It sounds like science fiction—more akin to the sketches of Leonardo da Vinci or Jules Verne than a genuine policy proposal. Indeed, many in the press have been quick to dismiss Musk’s vision as pure fantasy. Among the mocking headlines: “Billionaire Unveils Imaginary Space Train.” The skepticism is understandable: Musk himself pooh-poohed the project in a recent Tesla earnings call, assuring investors that he had no plans to actually build it. "I think I kind of shot myself by ever mentioning the Hyperloop," he said, characterizing it as a potential distraction from his day jobs at SpaceX and Tesla.

But Musk is an indomitable fellow—a man who lives to do things that others dismiss as impossible—and his press conference on Monday suggested he is struggling, and perhaps failing, to resist the temptation. Where once he had insisted that he was just floating an idea for others to take up, he now says he might build the thing himself—or at least a working prototype of it. In fact, it sounded over the course of the call as if he were becoming more convinced by the moment:

“I have to say I am somewhat tempted to at least make a demonstration product. I think I would have to punt it for a little bit of time, so it's not immediate. ... But I've sort of come around a little bit on my thinking here. Maybe I could just do the beginning bit—create a subscale version that’s operating—and then hand it over to somebody else. Ironing out the details at a sub-scale level is a tricky thing ...

“I’m not trying to go make a ton of money on this but I would like to see it come to fruition, and I think it might help if I did a demonstration article. I think I probably will do that, actually.”

That unexpected U-turn led Dana Hull of the San Jose Mercury News to point out that this might require Musk to form a new company. In response, Musk reflexively reiterated that the Hyperloop idea is "low-priority relative to the core missions of Tesla and SpaceX.” Of course, he kind of has to say that, considering he’s the CEO of those companies. He mentioned again that he would be glad to see someone else take up the plans so he doesn't have to oversee it. But then he said once more, "I think it might help if I built a prototype ... There probably would be a company formed at some point." (Emphasis mine.)

Musk even went so far as to specify a possible location for the working prototype: SpaceX's facility in McGregor, Texas. A demonstration in a remote location would probably be wise, he added, since "you want to be able to iterate quickly on the design and address issues before putting it near something like the I-5" highway in California. And while the demonstration line would be much smaller than the real thing, it wouldn't be a Hyperloop for ants, as Derek Zoolander might say. Rather, "the demonstration article would itself be something you could ride on," Musk clarified.

Hyperloop capsule in tube cutaway with attached solar arrays.
Hyperloop tube with attached solar arrays.

Image courtesy Elon Musk/SpaceX

Musk acknowledged that ironing out some of the details would be tricky. That’s surely an understatement. So much could go wrong on the path from concept to completion that it’s highly unlikely anyone would attempt it unless Musk succeeded in his proof-of-concept first. (And if they did attempt it, it’s equally unlikely they would succeed. No one alive can match Musk’s track record of turning crazy transportation dreams into reality.) But if he does build it, and it works, California officials would be foolish not to at least consider the Hyperloop as alternative to the $68 billion rail line that it’s about to start building.

It’s not just that it would be faster and more futuristic. It’s that it would be—potentially, at least—far more practical. Whereas high-speed trains require either tunnels or elevated tracks built on a massive foundation, Musk believes the Hyperloop would be so light that it could be supported mostly by widely spaced pylons installed along California’s existing I-5 corridor. Where the interstate gets curvy, as in the winding Grapevine section, the Hyperloop would have to deviate from its path—no one wants to make a hairpin turn at 700 mph. But Musk points out that installing pylons on people’s land would be far easier and less intrusive than building train tracks on their property, as California is now fighting to be allowed to do. The effect at ground level, he insists, would be more like that of telephone poles than the “Berlin Wall” that some California residents fear with the bullet train.

No doubt this is all easier said than done, and I have a feeling some of the obstacles would be greater than Musk is letting on. When I pressed him on how the Hyperloop would deal with the twistiest and most mountainous portions of the route, he acknowledged that one might need to blast a few “short” tunnels. But he still thinks it will be far easier than high-speed rail. Predicting that the final construction costs will top $100 billion, Musk likened the line to "California's Amtrak" and suggested it would burden the state's taxpayers for generations. "That just doesn't seem wise for a state that was facing bankruptcy not that long ago."

Wise or not, California is unlikely to drop its plans just because one rich guy has a light bulb over his head. On the other hand, if Musk does build a demonstration line, and it's faster, cheaper, more energy-efficient, and requires seizing less private property than laying down train tracks, a change of plans might start to sound pretty appealing. That's a lot of ifs—but so is every big idea, in the beginning.

So, what should Musk call his new company?

Correction, Aug. 14, 2013: This article originally mischaracterized the primary propulsion mechanism that Elon Musk envisions for the Hyperloop. The pods would be propelled primarily by linear induction motors mounted along the tube, not by the nose-mounted electric compressor fan. The fan would play a minor role in propulsion, but its main purposes would be to prevent a build-up of air mass in front of the capsules and to supply the air needed for levitation. (Return.)

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