http://www.youtube.com/watch?v=E_hci9vrvfw
If it is real, then there is some serious forces going on there.
I’ve seen still pics of that before but never a video, It’s showing the need to properly vent a tank car.
It’s real. I’ve seen the same thing happen to septic tank pumpers if the pressure inside the tank is too far below the pressure outside. It doesn’t take much of an imbalance either. Just a difference of a few psi can be get it going, and once it starts it doesn’t stop until the pressure equalizes.
I’d hate to be the guy who had to clean up that mess.[:O]
True enough, Jeffery. A 1 psi difference is 144 pounds per square foot. A 6 psi difference is over 1/2 a ton per square foot. Considering all the square feet on the surface of a tank car, it’s easy to see how it could be crushed when the internal pressure drops.
Nature abhors a vacuum… so does my wife [(-D]
I’m sure it’s real, but also staged. Given the large number of observers standing around in hard hats I suspect there was some sort of test going on at the time. Either they were deliberately trying to find out what kind of pressure differential it took to implode the tank. Or they were trying to test something else and things went terribly, terribly wrong. [:O][banghead]
I think I saw this before and the accompanying text said it was a staged HAZMAT training session for the people who empty tanks filled with hazardous chemicals, and for firefighters, demonstrating for them what can happen if the tank is not properly vented.
Nature abhors a vacuum… so does my wife 
A vacuum cleaner is one of those rare devices that is only effective when it really, really sucks.
Andre
Standard tank cars can contain high pressure - up to 75 psi in some cases. They can’t tolerate more than a few psi of differential if their inernal pressure falls below the outside pressure.
This was demonstrated in a classic engineering blunder. When the Yosemite Valley’s bridge across the Exchequer Reservoir was being dismantled, the contractor rigged up a bunch of tank car bodies to act as pontoons, so the bridge could be floated to shore and dismantled for scrap. When the span hit the water the pontoons were forced down to a depth where the pressure differential was too great. They imploded, one after another - and the bridge span sank into the depths, lost beyond any hope of economic recovery.
Chuck (Modeling Central Japan in September, 1964)
After watching that video the only think I can think to say is “sorry about your tank car, I’ll try and be more careful the next time”.
That would make a pretty nifty diorama. Shown at a point just before they load the span onto the floating tank car bodies.
-George
It would also be neat to model an imploded tank car at an unloading facility. All you really need it a donor (preferably a very cheap model- my Walthers Gold funnel flow is a little to pricey for a volunteer…) and a hammer! [:D]
Hmm, methinks I just got an idea…
Also note that the video is in real time, not speeded up; the term is catestrophic implosion. [:O] The Mythbuster guys would love to be there for that demo!
For years, there used to be a squashed truck trailer like that stored conspiciously at a local trucking company’s site. I assumed it was some sort of object lesson/visible reminder.
Real. Thats why there are TWO Hoses to a tank car. One to suck and one to vent.
But what if it really, really sucks?
Me and my brother and father had a long argument a while ago when I mentioned that the vacuum sucked; guess I should have said the vacuum was crap…