i've just went through 11 pages to check and i believe 'whatever happened to the likely lads' hasn't been mentioned!
blue DMUs over one of the bridges in the opening titles, but mainly the first episode 'strangers on a train'
mk1 SK action, then a buffet car of some sort. doesn't seem to fit any mk1 layout, an open bar counter next to a bay of seats, then the vestibule partition. the detail does seem to be quite good though, even for a TV mockup.
later on, hilarious platform mix-up ensues at doncaster
1st part here, click on links for the rest
Clip of series - Strangers on Train
just remembered, a later episode, with the competitive bike-ride, they end up at some station waiting room on a sunday with no trains?