Trivia about this movie:

The engine that crashes into a derailed engine was moving at nearly 60 mph. The crash was staged in the town of Acquigny, with extensive safety precautions and special insurance. Only one take was possible, and seven cameras were used.

The engine that we see from track level as it's derailed was moving faster than intended. Three of the five cameras filming the derailment were smashed.

The filmmakers hired a train to carry their equipment from one location to another, and this is the train we see as the art train in the film

The engines and tanks required for some scenes made so much noise that "action" and "cut" were signaled by codes on the engines' whistles.

The air raid on the yards was filmed at Gargenville yard, outside Paris. More than 50 people under Lee Zavitz needed six weeks to plant and wire all the charges, which were blown up in less than a minute. This was done by a special arrangement with the French National Railway, which had been seeking to modernize the yard but lacked the funds to do it.

The primary steam locomotives in the film are Class 230Bs, #739 (leads the military train Paris to Vaires), 517 (art train until Rive-Reine crash), 855 (rear engine in Rive-Reine crash), and 711 (art train post-crash). These engines were built from 1901 to 1912, and were nearing the end of their long service life in 1964.