Desc: The Black Diamond Express: Directed by Howard Bretherton. With Monte Blue, Edna Murphy, Myrtle Stedman, Claire McDowell. Dan Foster (Monte Blue), the engineer of the Black Diamond Express express train falls in love with Jeanne Harmon (Edna Murphy), whose snobbish, high society mother, Mrs. Harmon (Myrtle Stedman), does not approve of the blue-collar, rough-at-the-edges Dan Foster as a suitable husband for Jeanne.