Being a railfan
(was one before I became an Elvis fan) I can tell you that this film is one definitely worth adding to your collection if you love trains or Johnny Cash music.
This film hits close to home for me, since some of the scenes were filmed here in Georgia. A few were filmed at the Six Flags Over Georgia Park's Steam Railroad and the Stone Mountain Park Railroad). Some other scenes were filmed in Chattanooga, TN at the railroad museum there.
Overall, a piece of Classic Johnny Cash...get this one if you can!