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.

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.

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.

Builder photo of Construction Number 1511 showing right side of 36 inch gauge Morrison, Gross and Company 24 Ton, Two Truck Heisler Geared Steam Locomotive Number 2 at Erie, Pennsylvania, October 1924. This locomotive was used for logging near Wallman, Maryland. Photograph by Schauble.

Builder photo of Construction Number 1190 showing right side of Mountain Timber Company 42 Ton Two Truck Heisler Geared Steam Locomotive Number 103 at Erie, Pennsylvania in February 1910. This locomotive was used in logging near Kalama, Washington. Photograph by Schauble.

Builder photo of Construction Number 1209 showing right side of Mountain Timber Company 26 Ton Two Truck Heisler Geared Steam Locomotive Number 104 at Erie, Pennsylvania, October 1910. This locomotive was used in logging near Kalama, Washington. Photograph by Schauble.

Builder photo of Construction Number 1212 showing right side of Mountain Timber Company 42 Ton Two Truck Heisler Geared Steam Locomotive Number 105 at Erie, Pennsylvania, May 1911. This locomotive was used in logging near Kalama, Washington. Photograph by Schauble.

Builder photo of Construction Number 1340 showing right side of 42 inch gauge Mowbray and Robinson Company 53 Ton Two Truck Heisler Geared Steam Locomotive Number 8 at Erie, Pennsylvania, June 1916. This locomotive was used for logging near Quicksand, Kentucky. Photograph by Schauble.

Builder photo of Construction Number 1456 showing right side of National Soapstone Company 22 Ton, Two Truck Heisler Geared Steam Locomotive Number 1 at Erie, Pennsylvania, February 1922. This locomotive was used for mining soapstone near West Jefferson, North Carolina. Photograph by Schauble.

Builder photo of Construction Number 1286 showing right side of Native Lumber Company 42 Ton Two Truck Heisler Geared Steam Locomotive Number 1 at Erie, Pennsylvania, September 1913. This locomotive was used for logging near Howison, Mississippi. Photograph by Schauble.