The Heisler locomotive is one of the three major types of geared steam locomotives and the last to be patented. Charles L. Heisler received a patent for the design in 1892, following the construction of a prototype in 1891. Somewhat similar to a Climax locomotive, Heisler's design featured two cylinders canted inwards at a 45-degree angle to form a ' V-twin' arrangement. Power then went to a longitudinal

drive shaft A drive shaft, driveshaft, driving shaft, tailshaft ( Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power and torque and rotation, usually used to conne ...

in the center of the frame that drove the outboard axle on each powered

truck A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame constructi ...

through bevel gears in an enclosed gearcase riding on the axle between the truck frames. The inboard axle on each truck was then driven from the outboard one by external side (connecting) rods. In 1897, Heisler received a patent on a three-truck locomotive.Charles L. Heisler, Locomotive
U.S. Patent 585,031
June 22, 1897. As with Class C

Shay locomotive The Shay locomotive is a geared steam locomotive that originated and was primarily used in North America. The locomotives were built to the patents of Ephraim Shay, who has been credited with the popularization of the concept of a ''geared s ...

s, the tender rode on the third truck. Unlike the Shay, Heisler's design did not have a continuous string of

line shaft A line shaft is a power-driven rotating shaft for power transmission that was used extensively from the Industrial Revolution until the early 20th century. Prior to the widespread use of electric motors small enough to be connected directly t ...

ing running the length of the engine. Instead, the tender truck was driven by a line shaft above the shaft driving the main engine trucks, connected to it through spur gears. This patent also covered use of a 4-cylinder 'vee four' cylinder configuration. The Heisler was the fastest of the geared steam locomotive designs, and yet was still claimed by its manufacturer to have the same low-speed hauling ability.

Builders

The first Heislers were built by the Dunkirk Engineering Company of

Dunkirk, New York Dunkirk is a city in Chautauqua County, New York, United States. It was settled around 1805 and incorporated in 1880. The population was 12,743 as of the 2020 census. Dunkirk is bordered on the north by Lake Erie. It shares a border with the vi ...

, at the time producer of their own design of geared locomotive (called th
Dunkirk
, of which the Heisler could be considered an improvement. They did not adopt the Heisler design, but in 1894 the Stearns Manufacturing Company of

Erie, Pennsylvania Erie (; ) is a city on the south shore of Lake Erie and the county seat of Erie County, Pennsylvania, United States. Erie is the fifth largest city in Pennsylvania and the largest city in Northwestern Pennsylvania with a population of 94,831 ...

started to produce Heislers, and did so until 1904. Reorganised as the

Heisler Locomotive Works The Heisler locomotive is one of the three major types of geared steam locomotives and the last to be patented. Charles L. Heisler received a patent for the design in 1892, following the construction of a prototype in 1891. Somewhat similar to a ...

in 1907, it produced locomotives of the Heisler design until 1941. A & G Price of Thames, New Zealand received an order for a Heisler locomotive in 1943 from Ogilvie and Co, sawmillers of Hokitika, who wanted to purchase a Heisler locomotive but were unable to do so as production of Heisler locomotives had ceased in 1941. The resulting locomotive, maker's N^O 148 of 1944, was the last Heisler-design steam locomotive to be built, and closely followed Heisler practice but with the addition of a Belpaire firebox and front-mounted water tanks that featured a unique curved leading edge.

Variants

Heislers were produced mostly in two- and three-truck variants in sizes ranging from . There was one single-truck, narrow gauge Heisler built, Lake Shore Stone Products Co. #7 for the Lake Shore Stone Products Co.
Lake Shore Stone Co., Milwaukee, Wisconsin?

Notable survivors

Roughly 625 Heislers were produced, of which some 35 still exist. Approximately eight of these survivors are currently operational.

Advantages and disadvantages

The Heisler locomotive's gearing was inside the frame and thus protected, unlike that of a

. However, the Heisler's drive shaft, which was located in the center of the frame, limited firebox space. For this reason, when A & G Price built their Heisler, in 1943, they used a Belpaire firebox, to mitigate problems with burning wood and accommodating the drive shaft.

References

External links