Shay locomotive
Geared steam locomotive From Wikipedia, the free encyclopedia
Geared steam locomotive From Wikipedia, the free encyclopedia
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 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. Shay locomotives were especially suited to logging, mining and industrial operations and could operate successfully on steep or poor quality track.
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Ephraim Shay (1839–1916), was a schoolteacher, a clerk in an American 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 wanted 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, allowing him to log all year round. Two years later he developed the idea of having an engine sit on a flatcar 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 with an engine supplied by William Crippen 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][better source needed]
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] These became known as Willamette locomotives. 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.
According to Lima Locomotive Works in 1925, "The Shay Geared Locomotive has a wide and varied range of service, being used in industrial, quarry, contractors, logging, mining and plantation work; (also on branch lines and mountain sections of trunk-line railways). It is especially adapted to industrial railroads in and around large manufacturing plants. Its value as a switching engine is due to the rapidity with which it will accelerate a load and to its ability to spot cars in a minimum of time. It is designed to take any curve on which standard cars can be operated."[9] The company emphasized its performance on "steep grades", "uneven track", and "track too light for a direct engine of the same axle load".[9]
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 lies in the fact 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 30 countries, either by Lima, or after they had reached the end of their usefulness in the US.
Approximately 2,770 Shay locomotives were built by Lima in four classes, from 6 to 160 short tons (5.4 to 142.9 long tons; 5.4 to 145.1 t), between 1878 and 1945.
Two 15 short tons (13 long tons; 14 t) Shays were built with two cylinders and three trucks.
Four Shays, 600 mm (1 ft 11+5⁄8 in) gauge, were built left-handed, all special ordered by the Sr. Octaviano B. Cabrera Co.,[10] San Luis de la Paz, Mexico.
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116 Shays survive today, some a combination of parts of two Shays.[11] This is a partial list:
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