Danger Signal on AllMovie

This programmer came out of Columbia, which, during the 1920s, was just another Poverty Row studio. Cyrus Browning (Robert Edeson) disowns his son because he disapproves of his marriage. When the wife, Mary Browning (Jane Novak), is widowed, she hands one of her sons over to Browning. In his grandfather's care, the boy, Ralph (Gaston Glass) grows up to be a spoiled young man, while the other son, Robert (Robert Gordon), learns the value of hard work and is devoted to his mother. Robert gets a job on the railroad where Ralph, with his superior connections, has become superintendent. Both men fall in love with Laura Whitman (Dorothy Revier), and this causes Robert to lose his job. He proves his mettle when a convict commandeers an engine is shot to death at the throttle. Robert goes after the runaway train on a motorcycle and beats it to a crossing where he switches it over to a side-track. This keeps it from colliding with the oncoming express. Robert wins Laura, and he and his mother become reconciled with old man Browning.