AllMovie

Ralph Lewis stars as "Jovial" Joe Ryan, an aging but still vital railroad engineer. Suffering from failing eyesight, Joe is victimized by Bert Allen (George Cheseboro), a younger man who covets both Joe's job and the old man's pretty daughter Grace (Jean Arthur). Reduced to working as a flagman thanks to Bert's chicanery, Joe devotes his spare time to developing a block signal, which will automatically stop a train in case of emergencies. As a result, Joe gets his old job back, his young rival is booted out, and Jean is able to marry the man of her dreams, bridge-builder Jack Milford (Hugh Allen). The Block Signal might be worth seeing if only to watch a very young Jean Arthur in one of her first major roles.