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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. Great Western Railway No. ...
Explanation and rationale
The steam locomotive, as commonly employed, has its pistons directly attached to cranks on the driving wheels; thus, there is no gearing, one revolution of the driving wheels is equivalent to one revolution of the crank and thus two power strokes per piston (the steam locomotive is double acting, unlike the more familiar internal combustion engine). Great Western Railway No. ...
piston + connecting rod In general, a piston is a sliding plug that fits closely inside the bore of a cylinder. ...
A crank is a bent portion of an axle, or shaft, or an arm keyed at right angles to the end of a shaft, by which motion is imparted to or received from it; also used to change circular into reciprocating motion, or reciprocating into circular motion. ...
On a steam locomotive, a driving wheel is a powered wheel which is driven by the locomotives pistons (or turbine, in the case of a steam turbine locomotive). ...
A colorized automobile engine An internal combustion engine is an engine that is powered by the expansion of hot combustion products of fuel directly acting within an engine. ...
The maximum rotational speed is fairly fixed for a given engine technology. Given the lack of any variable-ratio transmission between the piston engine and the wheels in the locomotive, the designer is forced to choose one compromise between desired torque and desired maximum speed; the radius of the driving wheels determines this. The radius of the crank affixed to the wheel is of course less than this; its radius determines the length of the piston stroke. This cannot be too large, for the locomotive will be unable to generate enough steam to supply those large cylinders at speed; it cannot be too small, or the starting torque and thus tractive effort will be too small, and the locomotive will not be able to start a train. In mechanics, a transmission or gearbox is the gear and/or hydraulic system that transmits mechanical power from a prime mover (which can be an engine or electric motor), to some form of useful output device. ...
A locomotive is a railway vehicle that provides the motive power for a train, and has no payload capacity of its own; its sole purpose is to move the train along the tracks. ...
The concept of torque in physics, also called moment or couple, originated with the work of Archimedes on levers. ...
Tractive effort is the pulling force exerted, normally by a locomotive, though the term could also be used for anything else that hauls a load. ...
Many applications required a low speed locomotive with ample starting tractive effort; industrial use, mines and quarries and logging operations, steeply graded lines and the like, especially when the track is cheaply built and not suited to high speeds anyway. Unfortunately, although the tradeoff of speed versus torque can be adjusted in favor of torque and tractive effort by reducing the size of the driving wheels, there is a practical limit below which this cannot be done without making the piston stroke too short on a directly driven locomotive. For another article about a different type of logging, see data logging. ...
The solution, of course, is to separate the crank from the wheels, firstly allowing for a reasonable piston stroke and crank radius without requiring larger than desired driving wheels, and secondly allowing for reduction in rotational speed via gearing. Such a locomotive is a geared locomotive. Most were and are still single speed, but some did employ a variable ratio gearbox and multiple ratios.
Types of Geared Locomotive Notable geared steam locomotives included: - The Shay locomotive, featuring an offset boiler with a multiple-cylinder engine affixed to it on the opposite side, driving a longitudinal shaft geared to the axles via bevel gears(see also Ephraim Shay, inventor).
- The Class B Climax locomotive, with two inclined cylinders driving a transverse crankshaft, geared to a longitudinal driveshaft placed centrally on the locomotive and driving the powered trucks via internal gearing. There was also an earlier Class A Climax with a vertically-mounted marine-type steam engine, working through a similar drive-line, via a two-speed gearbox.
- The Heisler locomotive, with a 'Vee-Twin' style steam engine, one cylinder each side of the boiler, affixed to a centrally located longitudinal driveshaft, again geared to the wheels.
- The Willamette locomotive was a clone of the Shay locomotive produced after key patents expired. West coast logging customers were clamoring for improvements in detail design and the application of more modern locomotive technology to the geared locomotive; Lima (manufacturers of the Shay) were dragging their heels. The Willamette was the response to that.
The vast majority of geared locomotives in the world were built to one of the first three designs, whether licensed and official, or clones built after the expiration of key patents. Of the types, the Shay locomotive was the most numerous and best known. The overwhelming majority operated on the North American continent, but with a number in use in various parts of South America and a fair number in Australia and New Zealand, including home-grown types. The Shay locomotive was the most popular and best-known type of geared steam locomotive. ...
Ephraim Shay, 1861 Ephraim Shay, 1880 Ephraim Shay in this later years. ...
Small Class B Climax locomotive owned by the Oregon Lumber Company. ...
A Heisler locomotive The Heisler locomotive was the last on the scene of the three major types of geared steam locomotive, Charles L. Heisler receiving a patent for the design in 1892 following the construction of a prototype in 1891. ...
The Willamette locomotive was a geared locomotive of the Shay type, built by the Willamette Iron and Steel Works of Portland, Oregon. ...
World map showing location of North America A satellite composite image of North America North America is a continent in the northern hemisphere, bounded on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the south by the Caribbean Sea, and on the west...
South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ...
European engineers preferred cogs to adhesion when force is an issue, possibly because the locomotives can be much lighter. Cog locomotives can also employ down-gearing. A satellite composite image of Europe Europe is geologically and geographically a peninsula, forming the westernmost part of Eurasia. ...
The rack rail on a cog railway. ...
Today Nowadays, none is in commercial use; however, one can still catch a geared locomotive in operation on numerous tourist lines. The Cass Scenic Railroad in West Virginia is probably the best example worldwide, being entirely hauled by geared locomotives, and featuring the largest Shay locomotive in existence, former Western Maryland #6, a 162-ton monster that is effectively still brand new, having seen only four years of operation before retirement. The railroad also owns a Climax locomotive and a Heisler locomotive, enabling all three types to be seen. Also a good place to see geared locomotives is the Roaring Camp and Big Trees Narrow-Gauge Railroad in Felton, California which has several operational Shays; the Georgetown Loop Railroad in Colorado also has operating Shay locomotives. State nickname: Mountain State Other U.S. States Capital Charleston Largest city Charleston Governor Joe Manchin (D) Official languages English Area 62,809 km² (41st) - Land 62,436 km² - Water 376 km² (0. ...
Western Maryland is the portion of U.S. state of Maryland that consists of Frederick, Washington, Allegany, and Garrett counties. ...
The Roaring Camp & Big Trees Narrow-Gauge Railroad is a narrow gauge tourist railroad in California that starts from the Roaring Camp depot in Felton and runs a loop up nearby Bear Mountain. ...
Felton is a census-designated place located in Santa Cruz County, California. ...
This is the article on the state. ...
There is a Class B Climax operating at Puffing Billy Railway in Victoria, Australia, and at least two in New Zealand, at Shantytown and at The Pukemiro Line. Shantytown also have a Heisler, whilst there are two Heislers and a Price Cb (Class A Climax clone) at Pukemiro.
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