I think this might be the most grimdark show about #trains that I've ever seen, and I've watched one analyzing the 1998 Eschede derailment.
This isn't even meant to cover a disaster, it's a BBC documentary showing the day-to-day operation of King's Cross as they prepared to open the new departures concourse in 2012.
https://www.youtube.com/watch?v=FJtnfv1N80I
(Hat tip to @coryw for linking it in IRC.)