Round-up on the Hyperloop

On Monday, Elon Musk released details of his Hyperloop proposal for 780-mile-per-hour travel between Los Angeles and San Francisco, and it landed with all the hype and hyperbole expected from someone with such stature. While articles around the world oo'd and ahh'd over the proposal - it will only cost one-tenth of California High-Speed Rail (CAHSR)! And only 35 minutes from LA to San Francisco! - observers with experience in transportation approached the concept with a cold eye. Taking into mind that good transportation projects, like all good projects, start with goals rather than technology, the response from them was overwhelmingly negative on Twitter and on the blogs.

Roughly speaking, the sketch of the Hyperloop's operations are full of sleights-of-hand and outright falsehoods. Perhaps the best overall analysis of the project comes from James Sinclair of Stop and Move. Sinclair writes, "Problem is, taking a look at the documents that came with the announcement, it seems to be a fantastic joke. [The Hyperloop's] claims do not appear to be true - his own proposal doesn't even get close to supporting them. "

Foremost in Sinclair's list of six problems is the claim that the Hyperloop extends from Los Angeles to San Francisco. That, according to the maps provided with the proposal, isn't true. Instead, the Hyperloop goes from Hayward to Sylmar, about an hour's travel time outside either city's center.

So that 35-minute ride? It's actually about 2:35, 6 minutes longer than the travel time for CAHSR. While we could move the stations, that would dramatically increase the cost. Most of CAHSR's costs are in the approaches to each downtown, and there's no reason it wouldn't be the same for the Hyperloop.

Sinclair goes on to examine the political and cost assumptions, which is to say, Musk has made none. Musk builds his whole cost estimate on the assumption that, because the Hyperloop's tubes will be built on viaducts, people won't have a problem with them crossing their property. Sinclair goes on:

To assume that people will willingly grant your line of support columns an easement is an exercise in the absurd.  Worse is the assumption that an aerial structure is popular.

Remember Cape Wind? It was a Massachusetts proposal to build an off-shore wind farm. Far away from homes and property, way out in the ocean. It got held up for years and years and years by lawsuit after lawsuit.

You know what the problem was? Views. Aesthetics. People didn't want to look at these things way out in the ocean.

People love their views. Farmers love their views. To assume that an aerial structure is your golden ticket out of years in the courtroom is plain idiocy.

The technology, arguably the most difficult piece to evaluate, was tackled by Alon Levy, the author of Pedestrian Observations. Levy first examines the assumption that an all-elevated system would save money. In short, the answer is no, building a bridge across the entire state would cost at least 10 times as much as Musk says, or roughly $60 billion. While less than the $63 billion of CAHSR, it's not much cheaper. And, as far as comfort goes, the Hyperloop ride won't be all that grand.

The extremely high speeds of the vacuum-tube technology the Hyperloop is built on will impose some significantly uncomfortable sideways and vertical jerks over the course of the journey, up to about o.5 gs. This is far, far higher than the maximum on any train the world, something that will certainly spill your coffee. Levy summarizes by saying, "Motion sickness is still to be fully expected in such a case."

Matt Johnson, one of the writers for Greater Greater Washington, found yet another way the Hyperloop comes up short: capacity.

According to Musk, pods would depart LA and San Francisco every 30 seconds during peak periods. Each pod can carry 28 passengers. That means that under the maximum throughput, the Hyperloop is capable of carrying 3,360 passengers each hour in each direction.

For context, a freeway lane can carry 2,000 cars per hour. A subway running at 3 minute headways (like the WMATA Red Line) can carry 36,000 passengers per hour. The California High Speed Rail, which this project is supposed to replace, will have a capacity of 12,000 passengers per hour.

That means that Musk's proposal can carry only 20-25% of the passengers of the California High-Speed Rail under ideal circumstances. But are those ideal circumstances reasonable? Probably not.

The Hyperloop pods will travel at up to 760 miles per hour, just under the speed of sound, with pods traveling about 30 seconds apart in the tube. They will have a maximum deceleration of 0.5 gs, which is equivalent to 10.9 mph per second. At that rate of braking, it will take a pod 68.4 seconds to come to a full stop.

That's a pretty significant issue because safe vehicle operation means never getting closer to the vehicle ahead than the distance it will take you to stop. If pod A were to experience a catastrophic air-skid failure, crash into the tube wall, and disintegrate, pod B, 30 seconds back, would not be able to stop short of the wreckage. In fact, pod C would also likely hit the wreckage of pods A and B.

That means that the minimum separation between pods is probably closer to 80 seconds or more. Not a big deal. It still means 45 departures per hour. But that's only 1,260 passengers per hour in capacity. That's 10% of what the California High-Speed Rail can carry.

With a capacity of 1,260 passengers per tube, that means that the Hyperloop would need 10 tubes in each direction (not 1) to move the same number of passengers as the proposed high-speed line. And that would push the cost up by 10, which is actually more than the cost of the HSR.

If we factor in Levy's arguments about the cost of the Hyperloop's viaducts, we end up with a 100-fold increase in cost to have equivalent capacity to CAHSR. As a reminder, that rockets a sane $6 billion to an absolutely absurd $600 billion.

There are other problems with the proposal, too. Robert Cruikshank of California High Speed Rail Blog addresses some of the criticisms of CAHSR by Musk (which is to say, many of them are simply falsehoods), while Clem Tillier, of Caltrain-HSR Compatibility Blog, brings a list of 8 show-stoppers in a comment on the same post, including issues with branches and resetting the system.

But why would Musk, a successful engineer and entrepreneur, put forward such a proposal? Sinclair speculates that it is, in fact, an attempt to draw away support from CAHSR by presenting "the mother of all false choices." Levy speculates instead that it's an exercise in hubris:

It’s possible to discover something new, but people who do almost always realize the context of the discovery. If Musk really found a way to build viaducts for $5 million per kilometer, this is a huge thing for civil engineering in general and he should announce this in the most general context of urban transportation, rather than the niche of intercity transportation. If Musk has experiments showing that it’s possible to have sharper turns or faster deceleration than claimed by Transrapid, then he’s made a major discovery in aviation and should announce it as such. That he thinks it just applies to his project suggests he doesn’t really have any real improvement.

I write this not to help bury Musk; I’m not nearly famous enough to even hit a nail in his coffin. I write this to point out that, in the US, people will treat any crank seriously if he has enough money or enough prowess in another field. A sufficiently rich person is surrounded by sycophants and stenographers who won’t check his numbers against anything.

Yet Musk, he says, is one of the people who are constantly told they don't need to build on the successes of others, and "that they’re smart enough they can reinvent everything and that the world will bow to their greatness."

To me, the Hyperloop is, as I said at the outset, an example of people putting technology before goals. We want to move a lot of people quickly between California's major population centers. High-speed rail, not Hyperloop vacuum train technology, is arguably the most cost-effective and safest way to do this.

Hyperloop technology may have use elsewhere, perhaps as point-to-point very-high-speed travel between two far-removed destinations, but, with only as much capacity as the Larkspur ferry (and a far less comfortable ride), it does not meet the needs of California. There can absolutely be improvements on CAHSR. Its alignment to enter the Bay Area and LA Basin is poor, it will likely restrict Caltrain operation, it's overpriced, the Transbay Terminal is a mess, and more. But at least it accomplishes the goals it sets out to do. The Hyperloop, as presented, cannot.