Tony Bryer wrote in message ...
This is not my specialist subject, but surely it is the case
that the crumpling up makes them safer. Wasn't it the case that
a number of rail crashes a while back were made much worse
because the carriages were built off incompressible underframes
and so rode up violently in a collision?

I think its the old stock with bodies built on frames rather than
monocoque construction where that occurs. I'm not sure crumple zones
on carraiges are a terribly good idea since in the rush hour a dozen
people or more might be standing in the bit that crumples besides which
in a major accident carraiges tend to go all over the place and don't
always impact head on with whatever they hit. Better to make the whole
design strong so that it doesn't fly apart and hope for the best I would
have thought. Besides , if you're doing 125mph or even 180mph in a eurostar
and theres an accident I doubt a few feet of crumple zone would make a blind
bit of difference.

B2003