Buckling of a Rail Car Tank under an internal vacuum.

This video shows the folly of an inadequate design and/or incorrect operating procedures. Apparently the rail car tank had been 'steamed out' and it was very hot inside; when it rained heavily; this caused it to rapidly cool inside and form an internal vacuum. The tank had a vent designed to release the surplus internal pressure; but not to 'release' an internal vacuum! Also, as the design of the tank was to operate at an internal pressure, it had no vacuum support rings on it (i.e. It was not ring-stiffened or corrugated; like a typical vessel under external hydrostatic pressure). The collapse occurred very quickly, as we have found with our experiments at the University of Portsmouth; see my home website on:

http://homepage.ntlworld.com/carl.ross/page3.htm

Under external hydrostatic pressure, a thin-walled circular cylinder can buckle (implode) at a small fraction of the internal pressure to cause the same vessel to explode [1].
Reference.
[1] Ross, C.T.F, (2001) "Pressure Vessels: External Pressure Technology", Horwood Publishers, Ltd., Chichester, UK.