So about that hyperloop

[Josh]

Zoom

Almost a year after Elon Musk, chief executive of Tesla Motors (TSLA) and SpaceX, first floated the idea of a superfast mode of transportation, he has finally revealed the details: a solar-powered, city-to-city elevated transit system that could take passengers and cars from Los Angeles to San Francisco in 30 minutes. In typical Musk fashion, the Hyperloop, as he calls it, immediately poses a challenge to the status quo—in this case, California’s $70 billion high-speed train that has been knocked by Musk and others as too expensive, too slow, and too impractical.

In Musk’s vision, the Hyperloop would transport people via aluminum pods enclosed inside of steel tubes. He describes the design as looking like a shotgun with the tubes running side by side for most of the journey and closing the loop at either end. These tubes would be mounted on columns 50 to 100 yards apart, and the pods inside would travel up to 800 miles per hour. Some of this Musk has hinted at before; he now adds that pods could ferry cars as well as people. “You just drive on, and the pod departs,” Musk told Bloomberg Businessweek in his first interview about the Hyperloop.

Musk has built his entrepreneurial career attacking businesses he deems inefficient or uninspiring. He co-founded PayPal in a bid to shake up the banking industry, then used the fortune he made selling the startup to eBay (EBAY) to fund equally ambitious efforts in transportation. Tesla Motors, for example, has created the highest-performing, highest-rated all-electric car and a complementary network of charging stations scattered around North America. Meanwhile, SpaceX competes against entire nations in the market to send up satellites and resupply the International Space Station.

In the case of the Hyperloop, Musk started focusing on public transportation after he grew disenchanted with the plans for California’s high-speed rail system. Construction on the highly political, $70 billion project is meant to begin in earnest this year, with plans to link cities from San Diego to Sacramento by 2029. “You have to look at what they say it will cost vs. the actual final costs, and I think it’s safe to say you’re talking about a $100 billion-plus train,” Musk says, adding that the train is too slow and a horrendous land rights mess.

Musk thinks the Hyperloop would avoid many of the land issues because it’s elevated. The tubes would, for the most part, follow I-5, the dreary but direct freeway between L.A. and San Francisco. Farmers would not have swaths of their land blocked by train tracks but could instead access their land between the columns. Musk figures the Hyperloop could be built for $6 billion with people-only pods, or $10 billion for the larger pods capable of holding people and cars. All together, his alternative would be four times as fast as California’s proposed train, at one-10th the cost. Tickets, Musk says, would be “much cheaper” than a plane ride.

As for safety? Musk has heard of it. “There’s an emergency brake,” he says. “Generally, though, the safe distance between the pods would be about 5 miles, so you could have about 70 pods between Los Angeles and San Francisco that leave every 30 seconds. It’s like getting a ride on Space Mountain at Disneyland.” Musk imagines that riding on the Hyperloop would be quite pleasant. “It would have less lateral acceleration—which is what tends to make people feel motion sick—than a subway ride, as the pod banks against the tube like an airplane,” he says. “Unlike an airplane, it is not subject to turbulence, so there are no sudden movements. It would feel supersmooth.”

The Hyperloop was designed to link cities less than 1,000 miles apart that have high amounts of traffic between them, Musk says. Under 1,000 miles, the Hyperloop could have a nice edge over planes, which need a lot of time to take off and land. “It makes sense for things like L.A. to San Francisco, New York to D.C., New York to Boston,” Musk says. “Over 1,000 miles, the tube cost starts to become prohibitive, and you don’t want tubes every which way. You don’t want to live in Tube Land.” Right?

In the months since Musk first mentioned the Hyperloop, there has been plenty of speculation. Critics, dealing with limited information, have contended that the specifications laid out by Musk would be nearly impossible to achieve. Such a long, pressurized tube would require an immense amount of energy while also producing tons of air friction and heat.

Now Musk argues that the Hyperloop represents a type of middle ground that other people have yet to consider. Instead of being a complete vacuum or running at normal conditions, the Hyperloop tubes would be under low pressure. “I think a lot of people tended to gravitate to one idea or the other as opposed to thinking about lower pressure,” Musk says. “I have never seen that idea anywhere.”

Inside the tubes, the pods would be mounted on thin skis made out of inconel, a trusted alloy of SpaceX that can withstand high pressure and heat. Air gets pumped through little holes in the skis to make an air cushion, Musk says. The front of the pod would have a pair of air jet inlets—sort of like the Concorde. An electric turbo compressor would compress the air from the nose and route it to the skis and to the cabin. Magnets on the skis, plus an electromagnetic pulse, would give the pod its initial thrust; reboosting motors along the route would keep the pod moving. And: no sonic boom. With warm air inside the tubes and high tailwinds, the pods could travel at high speeds without crossing the sound barrier. “The pod can go just below the speed of sound relative to the air,” Musk says.

So, science, or science fiction? About a dozen people at Tesla and SpaceX have helped Musk with the design and checked the physics behind the Hyperloop. I briefed Martin Simon, a professor of physics at UCLA, on some of the Hyperloop details, and he declared it feasible from a technological standpoint: “It does sound like it’s all done with known technology. It’s not like he’s counting on something brand new to be invented.”

Simon points out that the acceleration methods proposed by Musk are used at amusement parks to get a roller coaster going. Other companies have looked at these techniques for passenger and freight vehicles. What sets the Hyperloop apart, though, is the use of the air cushion to levitate the pods. “He has separated the air cushion and the linear induction drive, and that seems new,” Simon says, adding, “It would be cool if they had transparent tubes.”

The critics of California’s high-speed rail may be dismayed to learn that Musk does not plan to commercialize the Hyperloop technology for the time being. He’s posting the plans and asking for feedback and contemplating building a prototype. “I’m just putting this out there as an open source design,” he says. “There are sure to be suggestions out there for making this better, correcting any mistakes, and refining the design.” Musk maintains that he has too much on his plate to deal with bringing the Hyperloop to fruition. “I wish I had not mentioned it,” he says. “I still have to run SpaceX and Tesla, and it’s fucking hard.”

Musk says he would support another person or organization that wanted to make the Hyperloop a reality.

“It is a question of finding the right person and team to get behind it,” Musk says. “Creating a prototype is not that expensive.” But if no one advances or acts on Musk’s ideas, he may come back to the Hyperloop in a few years’ time and pursue it as part of Tesla. “Down the road, I might fund or advise on a Hyperloop project, but right now I can’t take my eye off the ball at either SpaceX or Tesla.”

I want this to be a thing. I want it to be a thing that can happen and does happen.

I'm sure nobody is really asking 'Why?' but I'll pretend one of you did.

Why? Because we need a bitchin' large-scale engineering project in this country. We need something cool as shit, and functional, and in direct denial of the insidious 'Can't-do' attitude that a lot of people are plagued with.

I'm not an engineer, but to me this certainly seems a lot less daunting that going from the basics of putting people in orbit to putting Armstrong on the moon in a decade or so.

[rhoenix]

I agree with Josh here, and for the same points. It has been quite a while since we as a people have felt inspired by something our country is attempting to be accomplish, and large-scale projects like this are an excellent way to do so.

[Hotfoot]

No, no, no, a thousand times no.

Let's get a high speed rail set up, let's repair and revitalize the rail industry.

THIS SHIT? Fuck me this is a bad idea, at least the way they're planning on doing it. Yeah, let's set up thousands of miles of highly specialized, high technology electromagnetic propulsion tubes that are kept at less than one atmosphere that will hurtle people at hundreds of miles an hour, potentially thousands if they get their way, and best yet, let's make it elevated above ground. Why? Because we haven't killed a bunch of people this way yet, we have to get stupid ideas in transit bingo before the Japanese do!

He's got balls, I'll give him that, but this is the point where I really see him getting in over his head. Never mind that if there's a problem with your ride, you can't get out of it or you'll probably die.

[Josh]

How much have you read on this?

The above-ground portion is to create the minimum surface footprint in order to avoid disrupting farmland and cut down on the land usage fights.

As proposed, this would not involve over a thousand miles of tubeway anywhere because the design doesn't work over a thousand miles. It's strictly a regional transit system that would do stuff like LA-Frisco or NYC-DC.

In the event of pressure loss they will have oxygen masks to deploy just like an airline, in the event of complete depressurization the tube will re-pressurize and the vehicles will be manually exited.

There'll be issues, sure, and unforeseen problems. But that's going with any new technology. Basically the same complaints could be applied to air travel, which still manages on occasion to kill a few hundred people in a go.

[Hotfoot]

1. Land usage rights be damned, you still need the thing to be supported and deal with things like settling into the ground warping the tubes, access for repair and maintenance crews, to say nothing of emergency services should a disaster happen. The biggest issue being the first, because this is not going to be light and you've got to find land in "as the crow flies" sort of territory that will be capable of supporting this multi-ton monstrosity that subjects itself to massive stresses under normal operation every few minutes over thousands of miles. Roads and train tracks can afford to have the difference of a few inches here and there because they're not attempting supersonic or near-sonic transit speeds. Never mind that you're still going to have most if not all of the same land rights issues anyway, and if simply elevating it solves that problem, then why don't they do the same thing with the trains?

2. The cost of rail technology is relatively well known because we've been working with it worldwide for well over a century. It's very efficient and the biggest issue here in the US is that we're not terrible fond of it anymore because it's not zoomy enough. This is brand new shit that's never been done before. The prices cited by the guy wanting to do it are frankly bullshit, because they don't KNOW the technical issues that they're going to face until they try. Yes, the concept is technically possible, but the cost of it is almost certainly going to be astronomically higher than whatever it is he's quoting here. The difference between SpaceX and this is that every major nation in the world has achieved some level of spaceflight within the last 100 years. This is entirely unproven territory.

3. When someone tells me that magnetically catapulting someone through a tube is somehow more energy efficient than using mechanical forces to take advantage of gravity or air pressure to move something, I have to laugh a little because where in the world is the mechanical advantage in fighting both inertia AND gravity?

4. Planes, trains and automobiles all have bulk transit options for carrying goods instead of people on the same transport mediums that people go on. This does not, which cuts down on its general utility as well as it's income/expansion potential. Yes, I understand that they could also add cargo pods, but once the size of the tube is set, you can't just go and magically make it bigger to handle various bulk cargo containers, you have to make a new one or repackage everything as it comes in. Like it or not, that has some inertia to it as well, welcome to the reason our automobiles are roughly wide enough to be pulled by a pair of horses.

[Hotfoot]

And yes, I realize I'm still talking about the cross-country version of this thing, because that's what was originally proposed, and they've been hemming and hawing over it for a while now. A smaller scale test is what they should be doing, clearly, but what's true over thousands of miles is still going to be true over hundreds, just not as much.

[Josh]

1. I'm no expert on the specific construction that would be involved on the pylons, vis a vis surface loads and ground compression and so on, so I'll have to concede that aspect. But with regards to land usage with regards to the surface disturbance, the specific point he's making is that pylons will be less disruptive than track laid out across the land for farms and livestock. As to why they don't do that for trains, maybe it's the issues you've raised for load and handling or it's the fact that elevation would take an already astronomically-expensive project and jacking it through the roof. The rail project was budgeted at sixty bil and they're already admitting it's going to overshoot that by a fair margin.

2. This aspect is the least worrisome to me, honestly. Yeah, I know that it'll jump his price margin and I can live with that. Even if it jumped the margin by tenfold it'd still clock in cheaper than the existing proposal. Given that the rail project currently proposed is likely to become another much-hated boondoggle, I'd rather throw the pennies at a project that would at least get more attention to service due to being novel and inventive. The fact that we know rail sp well points toward the fact that we've pretty much pushed rail to the limits of how it will likely be utilized in this country. There's an actual risk/reward to this project that interests me.

3. What I know of the energy efficiency on this relates to the ability of the design to recycle energy on the deceleration phase.

4. Adding a parallel cargo tube system alongside down the road would actually be advantageous, if the initial passenger system were to prove out. The main problem I see with the passenger system is that it is single point of failure in nature- if a tube is compromised, the loop is fucked and the best you can do is run shifts going back and forth on the single remaining track. A parallel cargo system would allow some traffic to be shifted onto that network to keep a level of service going.


In terms of safety and emergency response, this in many ways comes across as theoretically safer-by-the-numbers in terms of human exposure. As designed, the typical mishap will involve a unit with a max load of twelve people. Given the distance between the units, if something mashed up or blew up one unit, the others behind it would stop and make their way back to the point of origin via the emergency system while the ones ahead use the same system to proceed to their destination.

That compares favorably to the disaster potential from the average passenger airliner crash or loaded passenger train derailment scenarios. Given that you're routing this between major cities loaded with air assets, I'd expect the response plan to lean heavily on choppering people out in the event of a stranding. Banging it on the basis of difficulty of recovering people is akin to banging on intercontinental air travel for having the same potential problem on a much larger scale.

However, you are correct that maintenance access will be greatly complicated by the nature of this proposed construction. I'd expect that in other areas that aren't so contentious on land use as California, they'd probably go in for a more grounded system.

But really we won't get a true feel for the concept unless he or somebody else goes ahead with a prototype version to give us a functional proof of concept and gives us a much better picture of the actual function and bugs in the design.

To that end I'm not proposing that the current rail plan be scrapped, at least not in exchange for this. But I do want to see it tested because it could be fucking awesome.

[Hotfoot]

1. If the budget for the high speed train is reasonable or not I can't say. I have no idea how they came to that number nor do I care to really find out, because I'm sure it will frustrate me in some way shape or form. It's entirely possible the lands rights issues artificially drove up the price, it's possible someone is trying to pull a fast one, or it's possible this is just really expensive for some reason. Not sure why, but I'm pretty sure higher complexity untested stuff will end up costing more by the end of the day just on rebuilds alone.

2. The proposal listed, I sincerely doubt, is going to take into account all of the things already included in the existing proposal. It's like those computers that come out to be really good deals, only they don't include speakers, monitors, keyboards, mice, or any cables. Here's the thing though, you still have to do considerable testing and R&D before you can really roll this out, and there hasn't been any indication that this has been done yet. When they've got a couple of 10 mile lengths of tube for proof of concept, I'll be a little more interested in the prices they're quoting.

3. That can be done in any properly constructed system these days, from cars to trains to, well not planes YET, but give it time, I'm sure. The issue is that for propulsion of this sort, you have to either fight gravity or friction in some fashion or other. Either you're levitating the capsule, or you're dragging it. Now, if you've got some low-drag wheels or low friction rails, that's good, you've lowered the necessary amount of energy you have to use fighting those things, but you're not doing away with it entirely. Existing ground vehicles move by employing gravity and friction to help them move. There's energy lost, sure, and there's only so fast you can go before you start losing control of your propulsion method, but to hit the speeds they're talking about here you need to reduce the effects of friction and gravity as much as possible, that's why they want as much air as they can out of the tub, less air resistance. Throw in having to levitate the capsule and the cargo, which is likely to be anywhere from half a ton to two tons, depending (more if they build ones capable of carrying cars), and now you have to spend energy keeping that capsule away from the bottom of the tube, which you simply can't get back from slowing down because it was never used to speed up. If they use low friction materials, that brings up another issue, one of the friction created at high speeds. What's described as one of the possible methods is a set of low-friction skis at the bottom of the capsule. Problem is, low friction isn't no friction, you're still losing energy dragging it along the bottom of the tube, energy that is converted into heat along the bottom of the pod and the tube itself, and that as well is energy you're just never going to see again barring some new technology. Depending on the speeds involved, the number of pods flying by every minute, you could very rapidly end up with another problem entirely, that of very mismatched temperatures at different points in the tube, which can create additional stresses as well as another safety concern should someone need to exit the tube in an emergency.

4. Then we run into the issue of light rail versus heavy rail, I suppose. Not insurmountable, but we'll see.

The issue I have with the emergency services thing is that with the speeds they're planning on using, I'm not sure the distances involved are still safe. They're basically planning to throw people down a pipe at supersonic speeds, getting around the sound barrier by removing air so they can go faster without building up a shockwave. At the stated speeds above (roughly 800 MPH), you're looking at a mile every 4.5 seconds. At a five mile gap, that means that between pods is ~22.5 seconds. Let's say it takes half a second for the system to detect the fucked pod ahead of you, and it's a worst case scenario, it came to a dead stop. Now, assuming there is no damage to the rest of the tube, it has to bring you to a dead stop in 22 seconds from 800 miles and hour. It's doable, but it's not trivial. Moreover, it needs to be doable if there is total power loss within the system, or you've got a pileup potential just as bad as any airliner or train.

I'm not against them testing this technology and building proof of concept, but frankly I'm tired of guys like this promising the moon instead of, you know, doing it. Space X was really fucking cool, mostly because it put its money where its mouth was and did it. They didn't promise and plead with us that cool things were down the pipe, it showed us a cool thing that worked. This is a quite literal pipe dream that's been around for decades with everyone saying "man, it'd be cool if...".

[Josh]

Well that's what it looks like it's going to shape up as. Musk has essentially said he's probably going to go ahead with a proof of concept, and we'll see how it goes from there.