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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?
you will die. really no ifs ands or buts about it.
have you seen my sig? there are many others like it but none that are the same
IF the system started to have a slow leak the pod would have time to slow, air resistance would do it naturally if nothing else.
Also it's not like it cannot have basically "landing gear" that would be able to slow the pod from 700 MPH in the perfectly smooth sealed tube in the case that a real breach presented itself - but you do all realize that a pressure breach would not be instantaneous across the enter length of the tube, right? Then we are back to the case where pressure changes can be reacted to and the system brought to a gradual halt.
I sweat Slashdot has become a bastion of luddite nut-jobs, who seem to purposefully ignore physics. Shameful to see such a virulent example of this on the home page.
You all sound like the people who wouldn't get into the first automobiles... or modern day Amish who still will not, but at least the Amish people are generally useful.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
Worst case scenario is everyone dies, which isn't much different than a plane crash.
Evidently you aren't aware that 95.7% of surviving an accident in a plane. The vast majority of people actually do survive. When the National Transportation Safety Board studied accidents between 1983 and 2000 involving 53,487 passengers, they found that 51,207 survived.
It's unclear what the statistics might be for hyperloop but assuming instant fiery death is probably not going to be correct for the majority of failure modes.
think of the pressure wave of air rushing in and what that will do to any near by vehicle
There are engineering solutions to that - the most obvious would be emergency vents that open up in the event that pressure is lost in any part of the tube. You can also make the tube larger than it needs to be to let air circulate around the car (like in a regular subway) rather than pushing it like a piston through a tight cylinder. Even a total vacuum is only 1 atm, 14lbs sq in, or 100 kPa lower than ambient - so it's not like we're developing pressures beyond what large brakes could not overcome.
My critique is that the engineering solutions are all going to be complex, expensive and make the thing a white elephant - but it's completely feasible from a technical standpoint.
W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
If a hyperloop tube suffers a catastrophic breach, think of the pressure wave of air rushing in and what that will do to any near by vehicle.
A lot less than you'd think. The incoming air (in a worst-case breach) will be traveling at about the speed of sound, so with the train traveling at ~700mph, it'll be like a ~1400mph headwind for a half-second or so. Aerodynamic craft like airplanes can handle that easily, and I see little reason the hyperloop (which will also likely be aerodynamic, for technical reason) would be much different. It'll also be fairly heavy, which means a lot of inertia, so the brief pressure wave won't have much effect on the train's speed, either. After that, it'll just be traveling into a regular atmospheric headwind, which without propulsion will result in fairly rapid, but gradual, slowing to a halt, so no danger there. And that's a massive worst-case breach, where an entire section of vacuum tube completely vanishes. Sort of a large explosion, that'll never happen (and if you have access to a significant quantity of explosives there are much, much easier and more devastating targets to hit).
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
I suspect that if the vacuum failed at the moment the pod was drawing near, it would feel more like hitting a big air cushion, like at an amusement park. Not fun, but not fatal. We're talking about a multi-ton carriage with relatively small frontal area. If the rupture occurred further on down the line, the effect would be less violent, because in a tube, you're going to get a pressure gradient, not a "wall" as most people are describing it. Ironically, if the rupture occurs behind the pod, it would probably have no effect at all, as the pod would be outracing the pressure wave, and if the pod happened to not be traveling at full speed, the air would be trying to accelerate the pod, not slow it down.
Which has more power: the hammer, or the anvil?
The whitepaper described how to handle loss of pressure in the pod. Basically it boiled down to this:
1) If the leak is small enough, compensate with onboard emergency air supply until the destination is reached
2) If the leak is big enough, initiate a system-wide emergency stop and rapidly repressurize the tube.
You could arguably repressurize the tube faster than an aircraft could descend to a safe altitude.
Do you know how much kinetic energy a moving trainset has at 200mph, let alone 700mph? If there is an accident, that energy has to go somewhere, and wherever it goes, it will have the potential to do something that will kill people.
:. Ultimate Control Dedicated/VM Servers
Vacuum expansion joints are a thing. In those scenarios that awesome* force of vacuum gets contained by .... a small flexible polymer.
*Vacuum isn't an awesome force.
One atmosphere is 13psi.
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