Largely OT British Transport Films railway nostalgia porn.
However, it is beautifully filmed - none of that silly stiff-upper lift "how we'll beat Jerry" sort of production, it's got quite a swinging-sixties feel to it and a rather awesome Dick-Dale-esque soundtrack.
Anyway, my point is that it shows what they could achieve with the limited technology of steam trains backed up by an army of men in bunnets with shovels in the 1960s. No fluorescent vests required. Note also that the odd-few diesel trains are also running and the passengers are enjoying a traditional novelty activity called sitting.
And if that's not enough, there's always Snowdrift at Bleath Gill from 1955 -