Thanks for the acceleration explanation Max.

And other folks
Crush end loads. Chatsworth- the first car was telescoped by the locomotive- lots of improvement possible from those early Metrolink Locos in energy absorption and override protection. The coaches that had to deal only with each other fared well- the rear cars didn't even derail. Metrolink , again, derailment after hitting an auto- albeit well off the crossing- near Glendale, then the train hit a standing UP, so not all car-train collisions are a simple butting condition.

Hmm, the question of shorter platforms/trains is also interesting- The recent dicussion/explanation of BARTD headway limits, plus staff expenses, seems to indicate shorter is not better where capacity is needed.