Montana Western Steam Locomotive Number 10 at Conrad, Montana, 1339.

Montana Railroad 4-4-0, steam locomotive, circa 1890. Photo from J.M. Fredrickson Collection. Other Subject Classes: steam locomotive, railroad crew

Mon-Road (formerly Alaska Railroad) Steam Locomotive 557 at Moses Lake, Washington, undated. Photograph by Wade Stevenson. The Mon-Road was the fictional railroad name for the collection of Monte Holm in Moses Lake, Washington.

Mon Road Baldwin 2-8-0 steam locomotive number 557 (construction number 70490, built in December 1944 as United States Army 3523) at Moses Lake, Washington, circa 1995. It came to Alaska Railroad in 1945 and was retired in June 1963. It was sold to Michaelson Steel & Supply Co in 1964 and became Mon-Road 557 in 1965 and was taken out of service circa 1995. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, passenger train.

Builder photo of Construction Number 1251 showing right side of Moline Lumber Company 20 Ton Two Truck Heisler Geared Steam Locomotive Number 1 at Erie, Pennsylvania, May 1912. This locomotive was used for logging near Malvern, Arkansas. Photograph by Schauble.

1.5 inch scale model of a Heisler geared locomotive truck posed next to an actual truck with Heisler General Manager George L. Swabb at Erie, Pennsylvania. Photograph by Schauble.

1.5 inch scale model of a Heisler geared locomotive built for display at the 1915 Panama-Pacific International Exposition at Erie, Pennsylvania. Photograph by Schauble.

1.5 inch scale model of a Heisler geared locomotive built for display at the 1915 Panama-Pacific International Exposition with Heisler General Manager George L. Swabb to the right at Erie, Pennsylvania. Photograph by Schauble.

1.5 inch scale model of a Heisler geared locomotive built for display at the 1915 Panama-Pacific International Exposition with Heisler General Manager George L. Swabb at Erie, Pennsylvania. Photograph by Schauble.

Builder photo of Construction Number 1161 showing right side of Mississippi, Arkansas and Western Railway 23 Ton Two Truck Heisler Geared Steam Locomotive Number 11 at Erie, Pennsylvania in June 1909. This locomotive was controlled by the Bliss-Cook Oak Company and was used to haul logs near Blissville, Arkansas. Photograph by Schauble.