File:Heisler-type geared steam locomotive 3 (27704363341).jpg

This is a rare Heisler-type geared steam locomotive in the collection of the Railroad Museum of Pennsylvania in the town of Strasburg. The engine was built in 1918 by the Heisler Locomotive Works. It was used by various lumber companies before being retired from service in the mid-1960s.

From museum signage: "When North Carolina logging line operator F.A. Addington approached the Brooks Locomotive Works of Dunkirk, New York, for a new locomotive in 1891, the project was handed to mechanical engineer Charles Heisler. When a later change in management forced Heisler and his design out of the company, he looked elsewhere for a firm to manufacture his locomotives. Burnham, Perry and Williams, better known as the Baldwin Locomotive Works, referred Heisler to the Stearns Manufacturing Company in Erie, Pennsylvania. Stearns was already well known and respected for their stationary steam engines and saw mill components. Although the name of the company came to reflect the inventor, Stearn's own employee, George Swabb, deserved credit for perfecting Heisler's design and making it a success.

The Heisler was set apart from other geared engines by three features. First was its "V" type motor engine that uses two steam pistons to turn a central drive shaft to the two trucks. Second was the use of connecting rods on the outside of the truck frames to power the second axle. Lastly, the use of a heavy-cast gear case protected the gears and ensured the longevity of the locomotive. This protection made the Heisler much more suited for mining and quarry operations than locomotives offered by other builders.