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Ask Slashdot: What Would Happen If a Hyperloop Train Failed?
dryriver writes: I've been following Elon Musk's Hyperloop initiative with great interest. The idea of getting from one city to another at 700 MPH without having to suffer through an airport and all that jazz is revolutionary. I'm glad that somebody is trying to innovate in the area of land travel. My question though: When conventional trains going at much slower speeds derail or crash, the result is often serious injuries or deaths. What happens if something goes wrong with a 700 MPH Hyperloop train/pod or with part of the track? Would a Hyperloop accident at that speed even be survivable?
I should think a hose and shovel should do the job nicely.
We will bankrupt ourselves in the vain search for absolute security. -- Dwight D. Eisenhower
Trains derail because of a century-old standard makes them very badly attached to its rail. If you run into a tube, even if the tube cracks a bit, there is a good chance you still continue in the same direction the same way I can run peas in a straw with crack. I don't think catastrophic can't occur. I just think it's inherently more secure to run in a 360 degrees boundary tube than 2 littles track with no grip else than your own weight.
We don't know what will happen because it hasn't been engineered and built yet. Determining how it handles various types of failures will certainly be part of the engineering process. Worst case scenario is everyone dies, which isn't much different than a plane crash. But just like with a plane, plenty of fail safes will be there to allow for managed failures. Most catastrophic failures will probably just cause the train to come to a gradual halt.
-- All that is necessary for the triumph of evil is that good men do nothing. -- Edmund Burke
Ask a Medical Doctor in 1820 what would happen if a steam locomotive crashed... all manner of mayhem, injury and likely death - that's what the experts all said. Falling off a running horse is bad enough, but the speeds that are possible with rail transportation are far worse.
Hatch doors... which would be separate failure points along the way for the pressure difference to be changed.
Assume perfect seals and no malicious or accidental misuse of even a single hatch door. A tech team is sent out to to assist the passengers in getting out. You can't just open the hatch, you've 14.7 lbs of pressure per square inch trying to keep that door closed, assuming it swings out. Now you've got to pressurize either the entire system (so largely shutting it down), or the particular leg you are on. How long does this take? Now how long does it take to undo these steps?
Short of a 9/11, when there is an airplane crash, even an entire airport (or state) is shut down due to weather, the rest of the system keeps going.
This also aside from all of the issues related to thermal expansion & contraction of the materials, making the sealing even more difficult.
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The mortality rate for national newsworthy and international newsworthy airplane accidents is near 100%, hence the cognitive disconnect.
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Air fills the vacuum at the speed of sound.
Yes, exactly. Sound is not all that fast (six seconds to travel just a mile), mostly the pod would be so remote from the source of the leak it would have plenty of time to slow down to a reasonable speed before substantial pressure reached it. Also if we are talking about small leak its not like it would INSTANTLY be a huge volume of air in front of the pod, it would be a gradual loss of vacuum and therefore simply not the "wall of air" you are scare-mongering about.
And of course, the leak would have to occur in front of a moving pod instead of behind it to even be that much of a potential danger...
A wall of air hitting you at that speed would likely kill you.
Not at 70MPH instead of 700MPH, you blithering retard.
Also I've not seen any arguments for why emergency vacuum pumps placed along the tube would help eliminate the danger from common leaks? But you didn't even think that far you were just like YABBER YABBER YABBER FLOOM DOOM!! *throws hands in air and waves frantically like muppet on acid*
"There is more worth loving than we have strength to love." - Brian Jay Stanley
Actually, I suspect the most likely fatal failure is going to be loss of passenger pressurization, resulting in *loss of cargo*. Cabin depressurization of an airplane is bad, but still not as bad as being exposed to total vacuum, and a plane can dive to regain air pressure. When a hyperloop pod looses pressure, there's no place to run.
Which has more power: the hammer, or the anvil?
Perhaps a more salient question is sabotage.
Explosive charges attached to the tube that detonated five seconds before the arrival of a pod would likely kill everyone on board.
The space station's pressure, such as ISS, is kept at sea level (kind of surprised, but...). That means that you have 101 kPa of pressure differential, on THIN ALUMINUM.
Seriously, all of the space stations have had leaks. Most were caused by micrometeorites that hit them. How many have blown apart because of that? NONE.
For those that are claiming that hyperloop will blow up, note that the tubes will actually be STRONGER than any of the stations.
And for those claiming that physicists are saying otherwise, I would suggest that they are NOT working in the field since they are too stupid to know.
I prefer the "u" in honour as it seems to be missing these days.
Only got through about half the video, but it was pretty much entirely sensationalistic bullcrap. Take the idea that the car is going to tear through the vacuum chamber in case of failure. Why would it? The car is traveling forwards. Even if it got hit with the strongest pressure wave imaginable, it's going to be entirely from the front: none of that is going to translate into sideways motion that would result in significant stress on the tubing from the car. It's literally high school physics. Perhaps worst of all is this idea that a 1 atmosphere pressure wave will automatically "kill everyone in the car". Again, why would it? The car has significant forward momentum, and the momentum imparted by the pressure wave will be relatively tiny compared to that. People inside the car would feel a jolt, sure, but not a blast wave. We know the car can withstand 1 atmosphere of pressure, because it's a pressurized vehicle inside a vacuum: 1 atmosphere of stress is it's normal operating condition. And that's worst case scenario: in practice any holes will be much smaller than the diameter of the tube, so the inrush of air will be gentle breeze, not a pressure wave.
As for people suffocating in the tubes after a failure, that's even dumber. Failure almost always means loss of vacuum, and in cases where it doesn't the system can be repressurized while the emergency is dealt with. The only way people would suffocate is a failure in the vehicle itself resulting in that depressurizing, and there are ways around that. I will agree the idea of propelling the system with a turbine is a little silly, I can't see that being a practical final design.
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
Engineers tend to think statistically -- which is a good thing. But it can produce judgments which are contrary to common intuition. That's because intuition is, from an engineering standpoint, crap.
Take automobiles. Three thousand Americans die annually in cars -- that's like a 9/11 attack every year. Plus car accidents produce a bountiful annual crop of disfigurations and crippling injuries. Yet nobody is concerned about getting in a car. Planes on the other hand are much safer. Now as an engineer trained to use numbers as your yardstick, the natural way of thinking is this: "Since cars are acceptably safe to the public, if I can get the deaths/mile figures for airplanes down to the same level my job is done." Except that plane failures are often spectacularly horrific. People are naturally terrified of them. It's common sense to be afraid of something that moves at hundreds of mile per hour thousands of feet in the air.
So people demand very high levels of safety for aviation, which drives the cost of air travel up. OK, then; that means rationally they should also want the same deal for automobiles, which are by every measure much more dangerous. Except no, every time someone proposes making safety improvements people resist the cost, even though on a dollar per life saved basis the make much more sense than trying to make airliners even safer.
Conclusion: the natural human emotional response to risk and cost is hopelessly borked.
Now the Hyperloop is a novel form of transportation, and our bias against novelty when it comes to fear means that people will demand it be designed to be much safer than air travel even. And by design it probably is. But given the physical nature of the thing, lurking out on the tail end of the probability curve there are no doubt potential events of spectacular carnage. But they are so unlikely that given the number of people who are expected to ride the system it makes no sense.
I don't know specifically what those scenarios are; I'm not a Hyperloop engineer. But if they do exist it may be that I'm literally better off knowing.
It has nothing to do with statistics or common sense.
It has to do with control. Getting into a car meaning you or the person you trust to drive you has a great deal of control over the situation, from driving to knowing the reliability of the vehicle to avoiding external threats from other idiots on the road. Getting into the plane means you have no control and have to trust a stranger for everything.