In preference to removing various walls from the sets, director Richard Fleischer decided to make extensive use of a handheld camera that could be brought into rooms; this was one of the first films to do so. To save money, the train sets were rigidly fixed to the floor and the camera was moved to simulate the train rocking.
The soundtrack of the movie is diegetic: its only music comes from a few brief moments from a radio and phonograph.
Filmed in 1950 but not released until 1952. According to director Richard Fleischer, when the film was finished, RKO Pictures owner Howard Hughes heard good things about it and ordered that a copy of it be delivered to him so he could screen it in his private projection room. The film stayed in the projection room for more than a year, apparently because the eccentric Hughes forgot about it.
The movie was shot in 13 days, and the only part filmed on board a train was a few seconds of the arrival at the Los Angeles' Union Station.
According to a May 1952 Los Angeles Examiner item, the film cost approximately $200,000 to make and was a sleeper hit for RKO. Reviewers praised the picture's tautness and imaginative camera angles. Many film historians consider the film to be one of the best pictures ever produced at RKO and a quintessential example of the film noir genre. Well-received at the time of its release, the production was made as a model B movie and, in fact, was RKO's biggest money-maker of 1952.