I'm also a little unclear how humans could survive a 100mph crash even if their container makes it through. If they were wearing a 4-point harness, I guess? Do they build crumple zones into train cars? Or... just rely on utterly demolishing anything they hit so the deceleration is kept under control? (https://www.reddit.com/r/BitchImATrain/)

Some nice analysis of survivable deceleration here (with restraints): https://aviation.stackexchange.com/questions/16545/even-afte... (100mph=44m/s)