Hot Lead (1951)

Recently released from prison, nice guy Dave Collins finds himself unwillingly mixed up with his old outlaw acquaintances Turk Thorne and his gang as they try to use his telegraphy talents to zero in on the arrival of a gold shipment on the local train. Taking a liking to Collins, cowboys Tim Holt and Chito Rafferty get him to agree to help set a trap for the train robbers