Andyroo:
The big square bit and the bit with the wheels come apart.
Thats usually called “an accident” and “it was like that when I got it” and “who left that low bridge there” 
MrFlibble:
el gordo 78:
newbie question alert - what’s a demount?A demount is where the box containing the goods can come off the chassis which carries it. Almost the same as a container, except that you get curtainside versions, etc. and they have their own legs so that you can just drive underneath them to pick them up/drop them off.
You mean, in a “Controlled Manner” rather than doing a RoRo impression 
A demount is when the shunter does not lock the body on to the unit and sets off and turns to fast. and it falls offand lands on it 's side… laugh… not much
Probably not the same thing but I’ve seen the remains of a car an Iso container fell onto. The car used to be a top-of-the range Range Rover. I was quite surprised at what was left visible…