According to Ben Mankiewicz on TCM, Barbara Stanwyck did her own stunts during the waterfall scene, and despite becoming black and blue, never held up the production.
Warner Brothers also released this movie in 3-D.
According to a contemporary article in the Los Angeles Times, Alan Ladd and Kirk Douglas were being considered for the male lead in this film.
The locomotive used in this film is the "Sierra No. 3," built in 1891 by the Rogers Locomotive and Machine Works in Paterson, New Jersey. It is probably the most-filmed locomotive in history, being featured in scores of motion pictures and television productions in the 20th century. It underwent a three-year overhaul costing $1.6M and returned to service in 2010.
This is the third of four collaborations between Barbara Stanwyck and Fred MacMurray. In chronological order, the films are L'Aventure d'une nuit (1939), Assurance sur la mort (1944), Le voleur de minuit (1953), and Demain est un autre jour (1956).