In Episode 1 of The Saint, "The Talented Husband" from 1962, the action takes place in Cookham, on the single track branch between Maidenhead and High Wycombe. The ungodly gets on the train at what I'm pretty sure is the real Cookham station, and thunders down a double track main line past upper quadrant signals behind a Black 5, although we see the end of the real Western Region branch train leaving the platform. He changes from his suit into his disguise as the female housekeeper, gets off at the next station, presumably Furze Platt Halt, and goes home to prepare the evil deed. Later in the day, back in disguise, he gets on the train again to go to London.
That night he leaves Paddington station behind a BR standard of some sort that magically changes into a Black 5, and returns home.