The “s” shape of trains in collision, “rattle off on both sides” is a natural product of physics. As the front of one car leaves the track the car tends to pivot and steer the following car to the opposite side and will cause it to pivot which will then steer the following and on and on.
Barring other intrusions in the process
Excellent explanation, CH. I was going to offer to work out some vectors for DoughtyOne, but it’s really way too late in the day for me. (And I just got back home from a funeral.) ___ :-(
In fact, it can be seen in the pic in post 53 that several cars followed the engine off the track, but eventually the rear end of a car kicked to the left, and some following cars relatively (relatively!) unhindered thundered down the left side of the embankment.
It’s also worth noting that some of the rearmost cars may not have even been in the curve as the derailment and abrupt slowing began.
Someone mentioned that a simulation had already been done - a link would be most interesting...
I’M trying to imagine tooling down the highway and suddenly a train car or locomotive is coming at me!