Quickly releasing liquid from the bottom of the sealed tank could draw enough vacuum inside to crush it as well, so long as the weight of the liquid causes the pressure at the drain to greatly exceed atmospheric pressure.

(@Kent, Nice explanation, thanks — but do you mean you mean bulkhead rather than bulwark? A bulwark is a defensive wall, like a fortification; a bulkhead is a partition, usually inside a boat or submarine, that strengthens it and prevents leaks or fires from spreading.)

Seriously funny.

By the way, thats an railroad tanker from Eva Eisenbahn Verkehrsgesellschaft AG ( railroad traffic corporation ) from Germany. It is used to transport crude and heavy fuel oil from northern german oilfields and refineries.

No heat >50°C involved here.

I’m with you. It was obviously an invisible fist, for there’s no force in nature that could wreck that kind of havoc. We must find the invisible fist, befriend it, and make it protect us from the far unfriendlier invisible foot, and the deadly invisible stream of urine.

Obviously Kent knows the distinction between pressure and force, but it’s like nails on a blackboard (or people saying “less” when they mean “fewer”) when I hear them interchanged.

To withstand that kind of pressure, a tanker car would need to be built like a submarine with massive steel walls and internal bulwarks. Of course they are not, which is why they must be vented when being pumped dry of liquid so the atmospheric pressure inside and outside the car remains equalized.

By the way, anyone can demonstrate this same principle in their own kitchen. Take an empty aluminum soda can, pour a few spoonfuls of water into it and heat it on the stove until the water is boiling. Then use a pair of salad tongs to take the can, turn it upside down and insert it into a bowl of ice water. The aluminum can will instantly crush with a satisfying crunch.

I’m so easily amused these days. And I agree with LJames…it does look like a huge fist just punched it!

Try that (bad video quality but you get the gist of it) :
http://www.youtube.com/watch?v=qbakZL62d6U

Doesn’t take much.

Take a metal container (paint thinner container, used up, rinsed out outside, clean), pour some water in it, boil it on a stove, once it’s steaming… screw the cap back on. Kill the heat. Watch it implode.