Trivia

The 'Thunderbolt' is a genuine veteran locomotive, its real name is "Lion". It was built for the Liverpool and Manchester railway in 1838, making it 115 years old when it was used in the film.

The credited driver, fireman and guard were not actors, they were British Railways employees from Westbury depot and were originally to be uncredited extras. After director Charles Crichton spoke to them on location and realized they looked and sounded the part, they were given speaking roles.

Writer T.E.B. Clarke ("Tibby") was inspired to write the Titfield Thunderbolt saga after a 1951 visit to the volunteer-operated Talyllyn Railway, which carries passengers along the Cambrian coast between Tywyn and Abergynolwyn, in Wales. "The Titfield Thunderbolt" reflects Clarke's fascination with the volunteers' preservationist spirit there.

Godfrey Tearle was 68 years old at the time of filming, and despite his age, he was required to perform heavy labor like shoveling coal and pushing the Titfield Thunderbolt up the hill with George Relph. Soon after filming, he died of a heart attack.

John Gregson had never driven a car before making this film.