Continuity mistake: The caboose and troop cars were decoupled. Later, after Rev. Peabody disappears, the train is shown chugging along with all the cars. (00:55:00)
Factual error: All the couples on the train are modern and not correct for the period. Trackwork back then wasn't very good, considering the speed that the back end of the train is going it probably would have derailed long before it did. The caboose and the rest of the train seen to be just shunted off the track for the dramatic crash, realistically it would have flipped over and gone over the trestle.
Answer: Ben Johnson and Charles During. Their characters had guns pointed at them, they stopped the train suddenly to knock them off balance. As soon as Bronson and the Major jumped off the train, Johnson and During took control of the engine.