Shay locomotive

No. 7 Sonora Class C (three driven trucks and articulated tender)
Drive side of the Class B Shay locomotive No. 1 Dixiana at the Roaring Camp and Big Trees Narrow Gauge Railroad, Felton, California
Accessory side of the No. 1 Dixiana

The Shay locomotive was the most widely used geared steam locomotive. The locomotives were built to the patents of Ephraim Shay, who has been credited with the popularization of the concept of a geared steam locomotive. Although the design of Ephraim Shay's early locomotives differed from later ones, there is a clear line of development that joins all Shays.


Ephraim Shay (1839–1916), was a schoolteacher, a clerk in a Civil War hospital, a civil servant, a logger, a merchant, a railway owner, and an inventor who lived in Michigan.

In the 1860s he became a logger and wished to devise a better way to move logs to the mill than on winter snow sleds. He built his own tramway in 1875, on 2 ft 2 in (660 mm) gauge track on wooden ties. This was much more efficient than his competitors because he could log all year round.

Two years later he invented the Shay Locomotive. In about 1877 he developed the idea of having an engine sit on a flat car with a boiler, gears, and trucks that could pivot. The first Shay only had two cylinders and the front truck was mounted normally while the rear truck was fixed to the frame and could not swivel, much as normal drivers on a locomotive. He mounted the 3-foot (914 mm) diameter by 5-foot (1,524 mm) tall boiler centered on the car with the water tank over the front trucks and the Crippen's engine mounted crossways over the rear trucks. Shay experimented first with a chain drive from the engine through the floor to the truck axle. It is not known if he powered one or both axles, but he soon found that the chain drive was not practical and he next tried a belt drive. It did not take long for the idea to become popular.

Shay applied for and was issued a patent for the basic idea in 1881.[1] He patented an improved geared truck for his engines in 1901.[2]

Lima Locomotive Works of Lima, Ohio built Ephraim Shay's prototype engine in 1880.[3] Prior to 1884, all the Shays Lima produced weighed 10 to 15 short tons (8.9 to 13.4 long tons; 9.1 to 13.6 t) each and had just two cylinders. In 1884, they delivered the first 3-cylinder (Class B) Shay, and in 1885, the first 3-truck (Class C) Shay. The success of the Shay led to a major expansion and reorganization of the Lima company.[4] When Lima first received the Shay idea it was not impressed, until John Carnes influenced the company to use the idea, resulting in the classic Shay design.

In 1903, Lima could claim that it had delivered the "heaviest locomotive on drivers in the world", the first 4-truck (class D) Shay, weighing 140 short tons (120 long tons; 130 t). This was built for the El Paso Rock Island Line from Alamogordo, New Mexico to Cox Canyon, 31 miles (50 km) away over winding curves and grades of up to 6 %. The use of a two-truck tender was necessary because the poor water quality along the line meant that the locomotive had to carry enough water for a round trip.[5]

Lewis E. Feightner, working for Lima, patented improved engine mounting brackets and a superheater for the Shay in 1908 and 1909.[6][7]

After the basic Shay patents had expired, Willamette Iron and Steel Works of Portland, Oregon, manufactured Shay-type locomotives, and in 1927, Willamette obtained a patent on an improved geared truck for such locomotives.[8] Since "Shay" was a trademark of Lima, strictly speaking it is incorrect to refer to locomotives manufactured by Willamette and others as "Shays". Six Shay Patent locomotives, known as Henderson-style Shays, were built by the Michigan Iron Works in Cadillac, Michigan.


Shay locomotives had regular fire-tube boilers offset to the left to provide space for, and counterbalance the weight of, a two or three cylinder "motor," mounted vertically on the right with longitudinal drive shafts extending fore and aft from the crankshaft at wheel axle height. These shafts had universal joints and square sliding prismatic joints to accommodate the swiveling trucks. Each axle was driven by a separate bevel gear, with no side rods.

The strength of these engines is that all wheels, including, in some engines, those under the tender, are driven so that all the weight develops tractive effort. A high ratio of piston strokes to wheel revolutions allowed them to run at partial slip, where a conventional rod engine would spin its drive wheels and burn rails, losing all traction.

Shay locomotives were often known as sidewinders or stemwinders for their side-mounted drive shafts. Most were built for use in the United States, but many were exported, to about thirty countries, either by Lima, or after they had reached the end of their usefulness in the US.


Approximately 2770 Shay locomotives were built by Lima in four classes, from 6 to 160 tons between 1878 and 1945.

Note: Two 15 ton Shays were built with two cylinders and three trucks.

Twenty Class D shays were built. They were no more powerful than Class C, but had greater fuel and water capacity, resulting in improved adhesion.

Four Shays were built left-handed, all special ordered for the Sr. Octaviano B. Cabrera Co., San Luis de la Paz, Mexico.


The "Leetonia No. 1" at the Railroad Museum of Pennsylvania

Only 118 Shays survive today, some a combination of parts of two Shays.[9] Herewith a partial list:

Ely-Thomas Lumber Company No. 6 operating at New Jersey Museum of Transportation
Midwest Central Railroad Three-Truck Shay Number 9
Meadow River Lumber Co. No. 1 in August 1970



  1. Ephraim Shay, Locomotive-Engine, U.S. Patent 242,992, June 14, 1881.
  2. Ephraim Shay, Locomotive-Truck, U.S. Patent 706,604, August 12, 1902.
  3. "Shay" Locomotives at Work, The Locomotive, Vol XV, No. 198 (February 15, 1909); page 37.
  4. Angus Sinclair, Development of the Locomotive Engine, New York, 1907; page 566.
  5. H. C. Hammack, A Remarkable Locomotive -- Heaviest on Drivers in the World, Locomotive Engineers' Monthly Journal, Vol. XXXVII, No. 1 (Jan. 1903); page 51.
  6. Lewis E. Feightner, Locomotive Crank-Shaft Bracket, U.S. Patent 879,617, Feb. 18, 1908.
  7. Lewis E. Feightner, Superheater for Locomotive Boilers, U.S. Patent 939,237, Nov. 9, 1909.
  8. Albert Claypoole, Geared Locomotive, U.S. Patent 1,622,765, Mar. 29, 1927.
  9. "116 Known Surviving Shays." Accessed 2010-02-14.
  11. "sn-3345" Accessed 2010-02-21.
  12. Chappell, Gordon. "Meadow River Lumber Company No. 1". Steam Over Scranton: Special History Study, American Steam Locomotives. National Park Service. Retrieved March 13, 2012.
  13. Cook, Roger; Zimmermann, Karl (1992). The Western Maryland Railway: Fireballs and Black Diamonds (2nd ed.). Laurys Station, Pennsylvania: Garrigues House. ISBN 0-9620844-4-1.


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