Also worth noting that on another thread here recently it was reported that all three cars of the SWR class 159 involved in the Salisbury Tunnel collision have been cut up - I seem to recall there was some expectation that at least the seemingly unaffected rearmost coach might survive and see further service, but evidently not so.There weren’t any undamaged coaches in the collision, forces would have gone through both coaches in the set.
An example of this being the Clapham crash, the 12VEP that was on the Basingstoke train had a car written off in the middle of the train.