Right side view photo of a Heisler three truck locomotive with a diamond type frame with motor installed and waiting for the boiler at Erie, Pennsylvania. Photograph by Schauble.

Right side view photo from the rear of a Heisler three truck locomotive with a diamond type frame with motor installed and waiting for the boiler at Erie, Pennsylvania. Photograph by Schauble.

Right side view photo of a Heisler three truck locomotive with a diamond type frame with motor installed and waiting for the boiler at Erie, Pennsylvania. Photograph by Schauble.

Right side view photo of a Heisler two truck locomotive with a diamond type frame being assembled with motor installed and waiting for the boiler at Erie, Pennsylvania. Photograph by Schauble.

Left side view photo of a Heisler two truck locomotive with a "I" beam type frame with motor installed and waiting for the boiler at Erie, Pennsylvania. Photograph by Schauble.

Photo from the side of outside frame truck for Heisler narrow gauge geared locomotive at Erie, Pennsylvania. Photograph by Schauble.

Photo from the side of outside frame truck for Heisler narrow gauge geared locomotive at Erie, Pennsylvania. Photograph by Schauble.

Builder photo of Construction Number 1036 showing right side of Sierra Railway Company of California 50 Ton Two Truck Heisler Geared Steam Locomotive Number 9 at Erie, Pennsylvania in December 1899. Some of the early models were built with a water tank over the boiler. Photograph by Schauble.

Builder photo of Construction Number 1036 showing right front side of California 50 Ton Two Truck Heisler Geared Steam Locomotive Number 9 at Erie, Pennsylvania in December 1899. Some of the early models were built with a water tank over the boiler. Photograph by Schauble.

Builder photo of Construction Number 1349 showing right side of Smith Powers Logging Company 75 Ton Three Truck Heisler Geared Steam Locomotive Number 8 at Erie, Pennsylvania, October 1916. This locomotive was used for logging near Powers, Oregon. Photograph by Schauble.