The Iron Horse - Season 2 Episode 12
T Is for Traitor

Although Calhoun discovers that the man who saved Julie and Barnabas from ambush is a former railroad engineer branded as a traitor during the Civil War, he still decides to hire him, despite Daves objection and his own suspicions. Unfortunately, the man still has his old associates riding with him and they are all planning to steal the gold that the train is carrying.