What could be wrong/immoral in sending one or two NwR people out (as well as relief driver for TOC), photographing the scene for potential evidence etc then covering the body until the evening when it can be properly recovered at the end of service?
You are not dealing with a body though, the last one I saw (I wasnt directly involved) the train was doing about 50 (down Brighton Fast through Clapham jn) and the body was in about 6 distinct bits, I saw 3 of them including the main bit so if the body is disassembled to that degree at 50 imagine what would happen to it at 90 (or more) mph.
Hint, there was one at Woking on the up fast (100 mph) and he was scattered over 3 platforms (and lots of passengers).
The rest of you (very good) post has already been answered.
Anyway enough of the gruesome details, I firmly believe that somebody who is going to do the deed will either do it in private or in a public way but quickly, they will not wait for an audience.
Some will obviously disagree with me but that is my view and I am unanimous in that belief.
Incidentally for anyone wondering if there is some suicidal nutter driving trains (thats me before you get all arsey

) my episode was 22 years and 3 months ago so quite a while ago and life is now very good ta very muchly.