Two years ago, when Elon Musk first proposed Hyperloop as a faster, cheaper, and more entrepreneurial alternative to California High-Speed Rail, I explained in depth what was wrong with the proposal. The curve radii were too tight for passenger comfort, and any attempt to fix them would require more expensive civil infrastructure. In general, the cost estimates in the plan were laughably low. Musk has moved on, but another team has been trying to build the system. It is planning to build a test track in the next three years, a distance of 8 km, for $150 million.
Let us analyze these costs. The per-km cost of this scheme is about $19 million, which if costs don’t run over is reasonable for HSR flat terrain, if anything a bit low. California HSR’s Central Valley segments, in more urbanized areas, are about $24-27 million/km, ex-electrification and systems (which don’t add much). This, in principle, suggests the system could be built for about the same cost as conventional HSR. Of course, it’s already far more expensive than Musk’s original estimate of $6 billion for about 650 km (including tunnels), but it still sounds like a good deal – in theory.
In practice, I’d like to go back to my often-quoted sentence in my post from two years ago, that Hyperloop would be a barf ride. The plan is to run capsules at their full speed, but only when empty. Tests with passengers would be restricted to 160 mph, or about 260 km/h. If the picture in the article describing the test track is accurate, the turn looks like its radius is perhaps 800 meters. Passengers can’t ride through this at very high speed. Even at 260 km/h, it requires full canting, and will make passengers feel noticeable extra gravitational push, about 0.2 g.
The importance of this is that any attempt to build tracks at higher speed will run into problems with both horizontal and vertical curves very quickly. The picture depicts sleek viaducts in empty land; imagine much taller viaducts, to allow the track to curve more gently than the terrain. Once the terrain becomes problematic, as it does on the approaches to the mountain crossings from the Central Valley to both the Los Angeles Basin and the San Francisco Bay Area, costs go up. This is true for any mode of transportation, up to and including mountain roads with hairpin turns, but the higher the speed, the larger the cost differential. In this situation, 4 km horizontal curve radii and 20 km vertical curve radii (about absolute minimum for conventional HSR) are expensive; 20 km horizontal curves and 230 km vertical curves are far more so. And within the urban areas, the inability of the system to leverage legacy rail tracks forces expensive urban viaducts.
Essentially I accept everything you write.
But, but, but … isn’t part of the concept that the journey will be so quick that ride comfort will be very much secondary, and doesn’t have to match existing ground transport. Humans regularly voluntarily put themselves thru much worse on fair-ground roller-coaster rides. And anyone signing up for a near-space flight won’t be expecting it to be like a Airbus A380 ride or a Shanghai Maglev for that matter.
Clearly Hyperloop is only worth considering if it is either cheaper & easier (including politically) to build and operate, or is bloody fast.
No, on the contrary! Shorter in-vehicle time makes the access and egress more important, and that makes things like the plan for airport-style security theater worse. Show up at Sylmar (since they couldn’t afford to build it all the way to Downtown LA). Strip for security. Ride the train, in worse-than-airline comfort. Get off at Oakland, and then take a taxi to San Francisco in Bay Bridge traffic. If you do that, might as well fly.
I agree but that seems to be a reply to a question I didn’t pose?
My point was that a certain level of passenger discomfort would be tolerable if the trip had the huge advantage of speed and time saved (which I agree has to be city-centre to city-centre).
Would it? The breakeven point for flying vs. ground transportation in market share is considerably longer than the point at which total travel time is equal. In Europe, trains and planes are about equal when trains take 4 hours, at which point even with access and egress time flying is like an hour faster. The sequence of standing in line repeatedly and then sitting in a cramped 737 or 320 is not favorable to passengers.
As for Space Mountain… that’s not what I want in my ordinary intercity or commuter transportation.
As an example, Seville-Barcelona air links lose share to train, in a 1.000 km trip, 1h35m by plane or 5h10m by train, access and egress is the key issue
If it was 15 or 20 minutes, why not? As you point out you would have spent longer in some other form of tedious transport/bottleneck getting to the station (and longer standing in the various check-in lines at airports). Again, my point is if hyperloop could really achieve that with merely the discomfort of a roller-coaster (an exaggeration), it would still be a success, yes? NYC to WashDC is 3h on Acela and would be about 1h15m by HSR (320 kmph)(on proper track), about 30mins by Maglev but about 15m by Hyperloop.
Your argument appears to be that it can’t do the speed because of pax comfort, but is it really true? And from memory, the current Amtrak NEC is, relative to the rest of the world’s TGV, HSRs and Maglevs, like a roller-coaster. Another exaggeration but the smoothness of TGV is critical, especially to people like me who are a touch too sensitive to read or use a computer with much unruly travel motion; but if a trip is super-fast and is over by the time I would hardly have settled in my (TGV) seat, then I won’t complain. Just like I don’t demand TGV-smoothness on any city Metro trip I take. I think the main point of hyperloop is forgotten by some commenters. And–I suppose your point–if it can’t be built to attain those speeds then there is no point building it. (Well, there is a political point: since it will be “made in America” it is more likely to get built which is no small point.)
However … I always recommend that people use the TGV from Paris to the south, even as far as Nice which is at least 5 hours, because it is a great trip, compared to flying (the last hour is not TGV of course but is a great amble along the coast, sometimes right on the sand!). I’ll certainly take the TGV from Paris to Barcelona, or vice versa, for the same reasons.
It’s closer to 35 than to 15-20.
New York-Washington is maybe half an hour by air. People rarely fly it O&D.
I’ve checked around and something like 30% of people are *prone* to motion sickness. That population will not be interested in a “Space Mountain” Hyperloop trip AT ALL EVER. So you just lost 30% of your ridership.
HSR is pretty smooth. Even people who are prone to motion sickness often don’t get sick on HSR.
Nathanael (2015/12/05 – 12:02)
I’d question that figure mostly because it is very conditional. For example I am prone to it (at least headaches) only if I try to read or use a computer etc on a bus or car. But not on HSR. Motion sickness is not induced by motion per se, but by a conflict in what your brain interprets in signals coming from your eyes versus your sense of balance (vestibular organ in ears). So there are contexts where even people prone to motion sickness can experience extreme motion turbulence, eg. mountain biking, without a hint of it. It also takes time to develop.
My point was that the duration of the journey is critical to all these complaints. You are not going to complain about ride quality on the world’s Metros are you? Do you see 30% of Metro riders feeling motion sickness?
Please, let’s stop referring to roller-coaster rides. I may have been the one to first cite Musk on that, but I withdraw it as it was always an inappropriate metaphor. Having said that I just watched a tv doco on trains that showed a real roller-coaster. It was a feature, “Extreme Railways”, by Chris Tarrant (a Brit radio host or something like that) on a part of the Thai-Burma railway that was beyond incredible in its bounciness. Hard to believe a train could do that without derailing, and it went on for maybe an hour or more. Due to leaching away of poor ballast over the decades by tropical rain.
A rollercoaster ride lasts a couple minutes at most. Having one that lasts 30 minutes would be much less acceptable for most people. Which is probably for the best, because it’s not like the Hyperloop will have a particularly high capacity anyway.
Alon (2015/12/02 – 23:36)
My calcs make it 33 minutes by a Transrapid Maglev performing the same as at Shanghai, so the Hyperloop would be at least twice as fast; and if it isn’t then it really is nothing special, right?
But everyone is getting a bit carried away by the Musk quote re roller-coaster ride. Clearly it wouldn’t be anything as wild, and the g-forces would be through your seat or back. We already have a working example of a train that every day (if not all through the day) travels at 430kmph and acceleration/deceleration and turning are barely detectable by the passenger (except perhaps by concentrating on the horizon out the window), so why cannot double this speed work too? The answer, as I think Alon is trying to say, is that to do so would simply cost too much. Perhaps. And compared to what?
The issue of capacity is quite open. Musk may have pitched his fantasy as a hybrid of mass transit but “in your own car” (driving it onto a pod) but that won’t have survived for long. Making a pod carry 30 to 40 people would transform the carrying capacity. Let the engineers work on the fantasy for a while longer I say.
I should add that the Chuo Shinkansen is halfway there. About two thirds of the thing is in tunnels (very tight-fitting with essentially sealed train compartments, I learned from Alon) and I’d bet that the Hyperloop idea of using vacuum to drive it will quickly give way to maglev (which was mentioned in the very first exposition of Hyperloop). The biggest limitation of Maglev performance is wind resistance, which is why the Shanghai maglev operates at reduced speed except at peak hours when it works at its design speed of 430kmph. Likewise the Chuo Shinkansen will not travel at its 500+ kmph capability most of the time. This because of the power law of increasing energy required at higher speeds to combat air resistance.
takes a lot of energy to suck the air out of a tube too. Even more to suck it out of the front of the train and use it to levitate the train.
Adirondacker12800 (2015/12/03 – 23:33)
Yep, and why the notion of using air/vacuum in a push/pull system like those intra-office systems seems so unlikely to work on scale-up. And whatever the drive force it will still need a very robust guide system which I reckon means maglev. When you look at current hovercraft one is not impressed though I suppose they would behave a lot better in a enclosed tube.
Initial pumping out most air would be energy-expensive but maintaining it doesn’t have to be. In any case it would not be a vacuum but more like low-pressure, say equivalent to 30,000 ft or bit higher that planes fly in (though their height limits have as much to do with their need for oxygen).
Like most, I’m pretty sceptical of the Hyperloop idea but I support the research being done. The Japanese have about 48km of operational maglev track that could be a test bed for this idea.
The plan is to evacuate the air in the tube to 0.001 atm; planes fly at an altitude with maybe 0.25 atm.
The research is great! They’re just not going to do it faster-better-cheaper than conventional high-speed rail. That’s ridiculous thinking by software people who think everything is like social networking sites or e-commerce.
@ Michael.r.james and Alon
Most passenger planes have service ceilings between 29,000 ft (CRJ) and 45,000 ft (747, or B-52). This is set by primarily by the amount of air required to run a jet engine with sufficient thrust (more of a problem for a CRJ), and partly by Mach drag increasing relative to the plane’s stall speed (more of a problem for a 747, 777 or well-powered jet aircraft with high ceilings). At these altitudes, atmospheric pressure is around 0.05 to 0.15 atm.
Evacuating a volume to 0.001 atm isn’t terribly difficult and can be achieved with simple one-stage scroll pumps. Multi-stage high-volume centrifugal or turbine pumps could also work fairly cheaply. There would be some fairly significant out-gassing from water in order to get to 0.001 atm initially (at room temperature, water boils at about 0.01 atm).
There are other engineering challenges in addition to maintaining a good vacuum seal to running a vacuum railway. For instance, air cooling of heat generating components doesn’t exactly work when there’s no air. There are engineering solutions to these problems, but they have to be thought out and tested.
Fbfree (2015/12/04 – 11:04)
In a 500 km tube with profile of a train? And with trains (pods) moving at 1000+ kmph acting as the seal between 0.001 atm and high-pressure on the other side to drive it? Good luck with that.
I know the pressures at commercial flight altitude is of that order which is why I suggested it (to reduce resistance for maglev trains, not as motive force as in original Hyperloop concept). I don’t really know, but I would guess that might be possible without deploying the output of a power station to run vacuum pumps on a volume of about 14 million cubic metres (in Oz we would say that is 0.03 of a Sydharb (vol of Sydney Harbour is about 500GL) so maybe not so big?).
If they can get this included with the Six Flags annual pass I am game.
Great stuff, Alon. Especially liked reading all the other articles about HSR. Another issue that should be brought up about the Hyperloop is capacity issues. Musk stated that the Hyperloop would have a capacity of 840 passengers an hour; that’s still a far cry lower than the N700 Shinkansen that can fit 1200 passengers on one train, in relative comfort – and these trains leave every couple of minutes. Granted LA doesn’t nearly the population density as Tokyo, however with population increasing the US faster than other MDCs in relation, the need for capacity is a large reason why California and other states are going to simply ignore the Hyperloop as a viable option (apart from the fact that it doesn’t exist at the current moment).
Here’s a video I created on the Hyperloop that may interest you: https://www.youtube.com/watch?v=-hGcgW0N_Lk
As well as a documentary on HSR in the US with interviews from All Aboard Florida: https://www.youtube.com/watch?v=cyON0VPE5BA
A roller coaster ride is not tolerable for many people. How would the hyperloop comply with the ADA?
Probably the same way Leap did ;).
maybe Musk should tie-up with FedEx and do a trial on couriering Cargo between Los Angeles and San Francisco? I wonder if there is a business case for that, even if as a prototype/trial ?
Why would the route be different for Hyperloop vs HSR?
Different curve radii.
An analysis of costs vs. performance of a transport system has to be based on the reduction of total travel time in proportion to the investment made in building and maintaining the transport system. Even if hyperloop could be built and would not be too expensive, it suffers from some major flaws: it can only service a minimal amount of stations. What that means is that in most journeys, most of the time is spent in slow transport to get to the entry station or to go from the exit station to final destination.
The extra speed a hyperloop has, in most cases, therefore would not compensate for the loss of time you have for going to or from a hyperloop station.
Increasing the amount of stations in the case of hyperloop either makes no sense (it would seriously bring down the average speed) or means you have to double the infrastructure (you can not re-utilize a tube/track for two different services, what normal rail can because you can implement switches, and have a fast train service – not stopping every station – and a slow service – stopping every station – can partly reuse the same track) which means doubling the costs.
Outside isolated use-cases where this kind of scenario makes sense (two very populated areas) in the general case, and for a general public transport network, hyperloop does not make sense.
This is not a surprise, as realistic calculations for maglev transport system turned out to be less favourable then normal highspeed rail in cases where it was considered (europa/germany and china). The only maglev line ever built only connects a large city (Shanghai) with the airport.
Please see UltimateTiltTrain.com. My proposal is for a half-tube uTrack Train with no vacuum, no fixed rails, and no strong magnetic fields. This train could handle curve Tilts up to 45 deg and zoom up hills with Grades of 12 percent. Passenger comfort is foremost with flexible, lower routing casts.