This Twentieth Century Fox motion picture was filmed between Durango and Silverton, Colorado, on the Denver & Rio Grande Western Railroad Silverton branch. The Silverton branch became land-locked in 1971 when the track south of Durango was removed. The present Durango & Silverton Narrow Gauge Railroad purchased the line in 1981.

The movie is a musical comedy released on 19 May 1950 with principal actors Dan Daily, Anne Baxter, Walter Brennan, and Rory Calhoun. There's a cameo appearance by Marilyn Monroe that's barely noticeable.

The story line takes place in 1876 Colorado where the fictitious Tomahawk & Western Railroad is expanding through the Rockies. In order to retain its charter the railroad must have a train, with at least one paying passenger, reach Tomahawk from Epitaph (actually Silverton in both cases) by 5 Sep 1886. However, there's a gap in the tracks so the locomotive is hitched to a team of horses to be pulled over a mountain pass into Tomahawk. Several stagecoach operators, fearing a loss of revenue, try to stop the train along its route, but it all ends happily ever after, of course.

The entire movie, which may be viewed on YouTube, is about 90 minutes in length.

Rio Grande Southern locomotive number 20 was used during the filming but disguised with various features such as a baloon stack to imitate an earlier engine plus lettering as the Tomahawk & Western. It was named Emma Sweeny. Filming was created operating the train along the "High Line" of the Animas Canyon at one point.

A full-size mock-up of the Emma Sweeny for the motion picture was constructed mainly of wood for appearance in the movie and to be pulled by a team of horses. Later the wood model appeared as the Hooter Cannonball in the television series "Petticoat Junction". It then moved about the country through several owners being lettered as the Amador Cannonball in Jackson, California. Since 2017 it's been located at Santa Rita Park in Durango, Colorado, where it has been painstakingly restored, including some real craftsmanship wooden parts, back to its Emma Sweeny appearance since its arrival there in 2011.