Classic Streamliners - TRAINCYCLOPEDIA
CPR No. 4. the "T. D. Judah", a locomotive rebuilt as a 4-2-2 by the Central Pacific Railroad.
A schematic drawing of the 4-2-2 steam locomotive wheel arrangement. Four leading wheels on two axles, two powered driving wheels on one axle, and two trailing wheels on one axle. Front of the locomotive on the left.
4-2-2 "Bicycle" Steam Locomotive
Under the Whyte notation for the classification of steam locomotives, 4-2-2 represents the wheel arrangement of four leading wheels on two axles, two powered driving wheels on one axle, and two trailing wheels on one axle.
Like other steam locomotive types with single pairs of driving wheels, they were also known as singles.
The 4-2-2 configuration offered designers eight wheels to spread the weight of a larger locomotive, but prior to the introduction of bogies, created a long rigid wheelbase with limited adhesion. As a result, the type was relatively rare until the 1870s. The first steam locomotive made by Borsig of Berlin in 1841, the Borsig No 1, was a 4-2-2, but the company quickly reverted to the more common 2-2-2 configuration.
The T.D. Judah locomotive was built as a 4-2-4 by the Cooke Locomotive Works in 1863. It was purchased for use on the Central Pacific Railroad and in 1872 was rebuilt as a 4-2-2.
By 1900 typical loads on express trains had grown beyond the capabilities of 4-2-2 locomotives and the configuration was superseded by the 4-4-2.
Text: wikipedia.org. Images: Public Domain; http://www.commons.wikimedia.org (unless otherwise specified) and 17 U.S. Code § 107 fair use. References: Lewis, Robert G. The Handbook of American Railroads. New York: Simmons-Boardman Publishing Corporation, 1951, 2nd Edition 1956. Site Map Contact webmaster HERE.
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