Death Train

A man is supposed to guard a shipment of diamonds being sent by rail. But a man robs the train and kills the men guarding the diamonds. The robbers derail the train and hope to get away with their crime. The robbers get caught in Mexico and are sent to prison by rail. The robbers take over the prison train they are on. Will these robbers get away with their crime or will the bodyguard kill all of the robbers and reclaim the train?