Play Safe (1927)

"Are Thrills Comedy? They Are When Monty Banks, Thrill king of Comedy, Puts Them on the Screen."

A gang of bad guys menace a feller's gal. She hides in a freight car and a misstep sends the otherwise-empty train out of the station with the lever pushed to full speed. As the train gains speed, the captive's boyfriend must board the runaway train, repel the pursing gang, get his girl out of the box car, and somehow get the two of them to safety. Tunnels, a water tower, a steep grade, and a frayed rope complicate the hero's task.