Transport Expert Insists 'Don't Dismiss Wacky Hyperloop'

DavidGilbert99 writes "Since Elon Musk announced the details of Hyperloop earlier this week, we've seen a number of experts debunking the technology involved, but at least one is more upbeat about the possibility of 600MPH train travel. Speaking to Alistair Charlton at IBTimes UK, professor Phil Blythe from the Institute of Engineering and Technology said: 'My gut feeling is, don't dismiss it out of hand just because it sounds a bit wacky,' adding 'You're always going to have long distance travel, and if there was something that could replace air travel between cities and hubs, and is low carbon [with] low energy requirements, it make sense to explore it, it really does.'"

Comments

Sure it's a loopy idea

[serviscope_minor]

It is a loopy idea, but not fundementally unsound in any way.

Every aspect of it, from the induction motors, to the earthquake proofing to the aerodynamics to the solar power is all well understood.

The difficult bit is really the engineering on a large project and developing all the parts and actually building the thing. I wouldn't trust most people with it and the usual suspects for government contacting would surely make a massice hash of it and cause a 50x budget overrun.

But that's nothing to do with the project per-se. Musk does have the kind of track record showing he can pull off big, complex engineering projects which are generally regarded as difficult and expensive applications of existing tech. Not only pull them off but do them well, quickly and cheaply.

So please, don't bring up arichair engineer objections to the design without first reading that big, long document which covers most of them and actually providing some reasoning.

Re:Sure it's a loopy idea

[gweilo8888]

Land is going to be what kills this project, before it even gets as far as anything technical. How do you acquire the land for the route as a private entity, without eminent domain?

Every time you buy a parcel of land the neighboring parcels know they're suddenly worth a fortune to you, because you can't just go around them at 800 mph. You have to stay within safe and comfortable G-force maxima for your passengers, which means no more than gentle changes in routing -- and that means you'll have hundreds of hold-out roadblocks in the midst of your route, refusing to sell unless you can provide them with an instant and very comfortable retirement. And if you can't persuade them to sell... well, somehow you have to find a route around them, and buy even more property to make your new route happen.

And then there's the neighbors whose property you aren't buying who will mire you in lawsuits because they don't want an ugly Hyperloop system at the end of their property.

Re:Sure it's a loopy idea

[beelsebob]

Land is going to be what kills this project, before it even gets as far as anything technical. How do you acquire the land for the route as a private entity, without eminent domain?

If you had even read the basic media coverage of this, you would know that he is proposing mounting this over the central reservation on freeways, so no land purchasing would be necessary.

Re:Sure it's a loopy idea

[beelsebob]

It doesn't matter if they were designed for it or not. They happen to be straight enough anyway, bar a very few locations. This simplifies the land grab issue thousands of fold. Given that this is being proposed as an alternative for a rail link that requires a land grab along its entire route, that's a massively simplified problem.

Re:Sure it's a loopy idea

[Black Parrot]

It is a loopy idea, but not fundementally unsound in any way.

Ah, but that's irrelevant. The underlying plan is to build a prototype, get it panned on Top Gear, and sue them for lots of money.

Re:Sure it's a loopy idea

[beelsebob]

A quick look at the freeways between LA and SF shows that they are mostly straight, with only very minor turns occasionally. A quick look shows that there's only two places where the route curves more tightly than the 14km radius turn required to keep under 1g acceleration at 800mph. Both of these locations are close to the end points, where the thing would still be under acceleration anyway, and if you really wanted to run at 800mph through them, there are 14km radius turns available in the area.

Re:Sure it's a loopy idea

[rasmusbr]

Land is going to be what kills this project, before it even gets as far as anything technical. How do you acquire the land for the route as a private entity, without eminent domain?

Why would you?

There are 200+ national governments out there. Convince one of them that it makes sense partnering with you. Once the first hyperloop system is built other governments will follow, including the state of California sooner or later, assuming the system is vastly better than high speed rail. Governments are pretty thick but most of them won't turn down an obviously awesome offer that's going to create profits for businesses and jobs for citizens.

It does need to be really good to overcome the inertia of government stupidity coupled with big corporate lobbyism. There is already a maglev system called Transrapid that is somewhat better than HSR in almost every way (50% faster, slightly cheaper to operate, etc), but governments prefer to build steel on rails because it brings profit to several existing large corporations and their many lobbyists, as opposed to bringing profit to just the corporation that owns Transrapid and their (fewer) lobbyists.

Re:Sure it's a loopy idea

[bruce_the_loon]

Uh. nope. The passenger-only capsule is 15,000kg and the passenger+vehicle is 26,000kg. The only number close to 3,500lbs in the documents is the 3,500kg weight of the capsule external structure.

Re:Sure it's a loopy idea

[VortexCortex]

"Enhance."

Re:Sure it's a loopy idea

[beelsebob]

Why would you go anywhere near Santa Clara? The proposal is to go up the I5. And no one claimed there would be no deviation from the freeway, just only minor deviation. If you'd actually read the documentation you'd also see that where you do deviate the issue is far less of an issue than for a conventional railway, because being mid-air, the farmer only has to put up with a few pylons being placed in his field, rather than a 30m wide swath that he can't cross. The bottom line is that it is substantially easier to get this across the country, and requires substantially less land purchasing. Where it does involve land purchasing, it's much easier to convince the owners that it's okay, due to not cutting their land in half, and not taking a large section of it; and it's substantially cheaper because you only need to buy the land to site the pylon bases.

Generally, it's a win all round compared to railways.

Re:Sure it's a loopy idea

[fearofcarpet]

I'm not an armchair engineer, but I am a real scientist. And while I have never seen anything at this scale, I have read a lot of proposals. This one did not set off my general bullshit alarm.

I really, really like that Musk has everyone talking about the Hyperloop and the ancillary discussions of public transportation in general, but there are a couple of details that are glossed over in the big, long document. One is the acceleration/braking by linear induction motors. Correct me if I'm wrong, but he seems to jump from idea that they already work in rotary engines and that MVA inverters are already commercialized (in mining equipment and trains) to the conclusion that they therefore will work in the linear configuration shown in the document. The wording there was sneaky.

The second is holding a vacuum, ~0.001 Atm., through the whole tube. Has that ever been demonstrated on such a large scale? He shows some metrics from commercial pumps, but then seems to assume that they will scale constantly with volume... how many pumps? Spaced how? What sort of maintenance requirements? How long to pump down the shunts at stations where modules are loaded/unloaded? Vacuum is non-trivial at commercial scales. Perhaps this sort of thing is commonplace and I have just never seen it (and I have seen vacuum chambers that would accommodate a pickup truck). But it felt to me like he was making a lot of assumptions about how easy it is to work with vacuum at those scales.

Those are both issues that can be demonstrated/prototyped, but it is as naive to say that the proposal was anything more than a whitepaper as it is to dismiss the whole thing out of hand.

Re:Sure it's a loopy idea

[mobby_6kl]

Why not just look at Elon's PDF, which already has a map with all the radius circles drawn on it?

Re:Sure it's a loopy idea

[nojayuk]

The Japanese maglev testbed runs at 500km/h regularly, with record speeds of over 550km/h in open running, not in a vacuum tube. Most TGV/HSR/shinkansen fast rail tops out at about 320km/h -- I think there's some Chinese HSR that goes a bit faster on scheduled runs. The planned Tokyo-Nagoya maglev will start operating at 500km/h but they're laying out the track to go faster in the future as the engineering improves. That's not "slightly faster" than TGV.

Freight doesn't run on LGV, or if it does then the operators are crazy. Heavy freight cars would destroy the track which is optimised for high-speed passenger transport and slower freights would collapse the passenger scheduling to the point where delays and cancellations would be frequent, not a good selling point for HSR. I've made a lot of shinkansen trips over the past few years, only once did I end up on a delayed train. The rest arrived and departed on schedule to the second (and I mean that, the second-hand on the platform clock reaches "12" and the train starts moving.)

Re:Sure it's a loopy idea

[bondsbw]

Ever considered underneath the ocean? We are talking about connecting cities that are on the coast.

Re:Sure it's a loopy idea

[Anonymous Coward]

Without fail, every time some complex idea is written about on slashdot here come the slashdotters who spend two minutes thinking about it and are convinced they've thought of something obvious that somehow the people involved never considered.

Never fails. Smart people looking foolish by their own overconfidence. Yes, we know you're way smarter than the average knucklehead around you. And they have lame brained ideas all the time that you can quickly point out how dumb each idea is. It happens to all of us. But it only works with your local knuckleheads.

So just stop it. At the very least phrase your objection in the form of a question. And realize that the more obvious it seems to you the more likely it is that you are the one overlooking something.

Re:Sure it's a loopy idea

[tibit]

Correct me if I'm wrong, but he seems to jump from idea that they already work in rotary engines and that MVA inverters are already commercialized (in mining equipment and trains) to the conclusion that they therefore will work in the linear configuration shown in the document. The wording there was sneaky.

An acquaintance has a small demo unit made as an (expensive) novelty item sitting on his desk. It's an aluminum pendulum and a 3 phase linear motor (just because, as he says). Runs off a couple AA rechargeable batteries. The pendulum is a disk and can be converted to a balanced disk by removing a weight. Once converted, you flip a switch and instead of going back-and-frth, it can spin up to 20kRPM in about a minute. The configuration is entirely immaterial, it's really a very basic thing, electrodynamically speaking. After you press the brake button, it similarly stops in about 40 seconds, while recharging the batteries.

10% of the capacity of high-speed rail

[jfruh]

An actual transit engineer crunches the numbers here:

http://greatergreaterwashington.org/post/19848/musks-hyperloop-math-doesnt-add-up/

And finds that while the journey for individuals may be faster, the system as a whole would have one-tenth the capacity (i.e., the ability to move people in numbers) than the planned high-speed rail system. You could solve this problem by building 10 times as many tubes, of course, but that would eliminate the 90% cost savings Musk is touting.

The radically reduced travel times vs. HSR are also deceiving. The maps Musk released show the system travelling from the fringes of the Bay Area to the fringes of the LA area, because it's hard/expensive/impossible to get land for the straightaways you'd need for the project within densely built up urban areas. To get from San Francisco to the hyperloop station, or from the hyperloop station to downtown LA, you'd have to switch to local transit or drive, which will double or triple travel time. Not coincidentally, must of the construction and expense that adds to HSR's very high price tag will come in SF and LA urban areas, since that system goes from downtown to downtown.

Re:10% of the capacity of high-speed rail

[nblender]

The actual transit engineer certainly doesn't know how to think outside of the box ... And if you read his credentials, he's not a transit engineer (is there even such a thing?)... He's a civic planner who's been employed in his field for a short 7 years.

He says the headway is essentially restricted by the amount of time it takes for each pod to decelerate to a stop, close an airlock, pressurize the container, open the other airlock, etc ... Then trying to get the old arthritic passenget in/out of the pod in 60 seconds. Even I, a lowly firmware guy, can conceive of a few different ways to handle that. These are not huge obstacles on which to form the basis of analysis and reject the idea.

Re:10% of the capacity of high-speed rail

[Rakishi]

The maps Musk released show the system travelling from the fringes of the Bay Area to the fringes of the LA area, because it's hard/expensive/impossible to get land for the straightaways you'd need for the project within densely built up urban areas.

Most people in the Bay Area do not live or work in SF. In fact San Jose which is the south end of the Bay Area alone has almost 1 million people (and growing) compared to 800k in San Francisco (and not growing).

Not coincidentally, must of the construction and expense that adds to HSR's very high price tag will come in SF and LA urban areas, since that system goes from downtown to downtown.

That's because HSR needs to go to downtown to be even remotely competitive with airlines and thus viable. It's so much slower than an airplane it just can't be remotely as fast unless you add in all the commuting to station/airport time. The Hyperloop does not. It is as fast as an airplane if not faster. That's from station/airport to station/airport. So it can be just as fast an an airplane destination to destination despite not going to downtown since airports also don't go directly to downtown. If people care later on it can be expanded but initially it can compete on price for example.

Re:There's a big difference between

[tibit]

What do you crash into? There is a big difference between a head-on collision, and merely a slide along the tube without air cushioning. When you're in a tube, the only other thing you can crash into is another train that goes the same way (or has stopped). Since there's no on-board propulsion, there's no scenario in which a train can propulsively overtake and hit a train in the front. It can only happen if the train in the front brakes, and somehow this doesn't get the trains behind it to stop. Very, very unlikely. The braking systems would be entirely passive, so basically if you blow the fuses on all the on-board batteries, the thing mechanically brakes an in entirely passive fashion. Also, for the trains to stay unbraked, they must be in constant communications with the control center. Presumably if the communications are lost for more than a 100ms, the brakes come out.

Oh, and they are not stupid, they did plan the route in detail, with bend radii and speed profiles all included.