I know that there is a Pentrax video titled Journey to Yesterday on the making of the movie Denver and Rio Grande.
In the video it shows the 319 being painted red as a locomotive for the Santa Fe affiliate Railroad. In the movie it is a quick shot when they get the flat car and load it with TNT. In the Pentrax video it talks about how the locomotive was painted quick over night and then repainted back to the yellow.
Also the 319 or the 345 was a stand in when the 268 hits a rock slide early on in the movie. You can easily spot it by the panel cab vs the smooth side of the real 268
Always liked that movie.
Dan