The Shay locomotive was the most widely used geared steam locomotive. The Roaring Camp & Big Trees Railroad is a narrow gauge Tourist Railroad in California that starts from the Roaring Camp depot in Felton Felton is a Census-designated place (CDP in Santa Cruz County, California, United States. The Roaring Camp & Big Trees Railroad is a narrow gauge Tourist Railroad in California that starts from the Roaring Camp depot in Felton Felton is a Census-designated place (CDP in Santa Cruz County, California, United States. A geared steam locomotive is a type of Steam locomotive which uses reduction gearing in the drivetrain as opposed to the common directly-driven design They were built to the patents of Ephraim Shay, who can be fairly credited with the popularization of the concept of a geared steam locomotive. Ephraim Shay ( July 17 1839 &ndash April 19 1916) designed the first Shay locomotive and patented the type Although the design of Ephraim Shay's early locomotives differed from later ones, there is a clear line of development that joins all Shays.
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Builders
Shay locomotives were built by Lima Locomotive Works of Lima, Ohio, USA, although six Shay Patent locomotives, known as Henderson style Shays, were built by the Michigan Iron Works in Cadillac, Michigan, USA. Lima Locomotive Works was an American firm that manufactured Railroad Locomotives from the 1870s through the 1950s Lima (ˈlaɪmə is a city in the US state of Ohio and the County seat of Allen County. Cadillac is a city in the US state of Michigan and is the County seat of Wexford County. Geared locomotives built by Willamette and other manufactures are often incorrectly referred to as Shays.
Overview
Shay locomotives had regular fire-tube boilers offset to the left to leave room for 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. A fire-tube boiler is a type of boiler in which hot gases from the fire pass through one or more tubes within the boiler These shafts had universal joints and square sliding slip joints to accommodate motion of swiveling two axle trucks. A universal joint, U joint, Cardan joint, Hardy- Spicer joint, or Hooke's joint is a Each axle was driven by a separate bevel gear and used no side rods. Bevel gears are Gears where the axes of the two shafts intersect and the tooth-bearing faces of the gears themselves are conically shaped
Driving all wheels, even those of the tender, together with small diameter wheels were the strength of these engines, their entire weight developing tractive effort. Tractive Effort (abbr TE is the pulling force exerted normally by a Locomotive, though the term could also be used for anything else that pulls a load 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 on molten steel.
Shay locomotives were often known as sidewinders or stemwinders for their side-mounted drive shafts. Most were built for use in the United States, while many found their way to 30 additional countries, territories or provinces.
Problem
Although the Shay was the most common geared locomotive, it had a significant flaw that was not recognized or corrected by the manufacturer. Because the drive shaft lies outside the trucks, instead of in the center, truck rotation when following track curvature causes substantial drive line length change, unlike the central drive shafts of Heisler locomotives and Climax locomotives. The Heisler locomotive was the last variant of the three major types of Geared steam locomotive, Charles L A Climax locomotive is a type of Geared steam locomotive in which the two steam cylinders were attached to a transmission located under the center of the locomotive frame In modern drive shafts, this effect is accommodated by roller splines instead of bronze slip joints (shown between "Sonora's universal joints") that lose their ability to slide under high torque. Ball splines (Ball Spline bearings are a special type of Linear motion bearing that are used to provide nearly frictionless linear motion while allowing the member
Wreck photographs in logging literature show Shay locomotives, before or after uphill curves, where they failed to respond to change in track curvature, thereby running off the track "for no apparent reason. " Some texts refer to these locomotives as "rail spreaders" and "flange hounds," both characteristics of trucks that do not steer freely with heavy drive shaft torque.
Classes
2768 Shay locomotives were built by Lima in four classes, from 6 to 160 tons between 1878 and 1945.
- Class A: two cylinders, two trucks. Weights between 6 and 24 tons.
- Class B: three cylinders, two trucks. Weights between 10 and 80 tons.
- Class C: three cylinders, three trucks. Weights between 40 and 160 tons.
- Class D: three cylinders, four trucks. Weights of 100 and 150 tons.
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.
Survivors
Only 115 Shays survive today, some a combination of parts of two Shays. The oldest surviving Shay sn-122, built in 1884, is currently displayed in Redding CA, at Turtle Bay Exploration Park. Turtle Bay Exploration Park, located in in Redding California, is a museum complex that interprets the relationship between humans and nature The last Shay, sn-3354 built in 1945, still operates on the Cass Scenic Railroad State Park. Cass Scenic Railroad State Park is a State Park located in Cass, Pocahontas County, West Virginia. One of the largest Shays built, this 150 ton Class C locomotive was in service only five years when it was retired and placed in the Baltimore & Ohio Museum. In 1981 it was removed from static display, in exchange for a smaller Shay and a Porter locomotive, and placed in service on the Cass Scenic Railroad. Year 1981 ( MCMLXXXI) was a Common year starting on Thursday (link displays the 1981 H K Porter Inc (Porter manufactured light-duty Railroad Locomotives in the USA starting in 1866 It has now served in tourist and enthusiast service for a longer period than it did for its original owners. It is still in near-new condition. The Camino-Placerville & Lake Tahoe #2, a three-truck Shay, is on display at the Travel Town Museum in Los Angeles' Travel Town Museum. The Travel Town Museum is a Transport museum in Los Angeles, California. Los Angeles (lɑˈsændʒələs los ˈaŋxeles in Spanish) is the largest City in the state of California and the American West The Travel Town Museum is a Transport museum in Los Angeles, California. The Roaring Camp and Big Trees Narrow Gauge Railroad operates the class B Dixiana and the class C Sonora
Images
External links
- Cass Scenic Railroad
- Ephraim Shay website
- W&H Main Yards
- The Shay Locomotive at the Canada Science and Technology Museum
- El Dorado Western Railway blog Shay construction number 1896 under restoration
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