The Block Signal (1926)
The Block Signal plot
Though aging, railroad engineer "Jovial Joe" Ryan (Ralph Lewis) is still vital. Due to some eye problems, Joe falls victim to Bert Steele (George Chesebro), a young man who is after both Joe's job and his beautiful daughter Grace (Jean Arthur). Because of Bert's meddling, Joe is demoted to flagman. But he now has time to develop a new signaling system that automatically stops a train in the event of an emergency. This invention reinstates Joe and returns him to his old job. His young rival is fired and Grace can now marry the man of her dreams, the handsome bridge builder Jack Milford (Hugh Allen).