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A 4-4-2 Locomotive refers to the classification of locomotives under the Whyte notation for the classification of steam locomotives by wheel arrangement, where represents a configuration of four leading wheels on two axles, usually in a leading bogie with a single pivot point, four powered and coupled driving wheels on two axles giving tractive effort, and two trailing wheels on one axle, usually in a trailing truck which supports part of the weight of the boiler and firebox and gives the class its main improvement over the configuration. This wheel arrangement is commonly known as the Atlantic type, although it is also sometimes called a Milwaukee or 4-4-2 Milwaukee, after the Milwaukee Road which employed them in high speed passenger railroad uses. Other equivalent classifications are: * UIC classification: 2B1 (also known as German and Italian classifications) * French classification: 221 (also known as Spanish classification) * Turkish classification: 25 * Swiss classification: 2/5 ==Overview== While the wheel arrangement and type name Atlantic would come to fame in the fast passenger service competition between railroads in the United States by mid-1895, the tank locomotive version of the Atlantic type first made its appearance in the United Kingdom (UK) in 1880, when William Adams designed the 1 Class T of the London, Tilbury and Southend Railway (LT&SR). The is the tank equivalent of a 4-4-0 American tender locomotive, but with the frame extended to allow for a fuel bunker behind the cab. This necessitated the addition of a trailing truck to support the additional weight at the rear end of the locomotive. As such, the tank version of the wheel arrangement appeared earlier than the tender version. The tender version of the originated in the United States of America, evolving from the less stable 2-4-2 Columbia wheel arrangement, and was built especially for mainline passenger express services. One advantage of the type over its predecessor 4-4-0 American type was that the trailing wheels allowed a larger and deeper firebox to be placed behind the driving wheels.〔Ellis, Hamilton. (1949). ''Some Classic Locomotives''. London: George Allen & Unwin. .〕 The first use of the wheel arrangement for a tender locomotive was under an experimental double-firebox locomotive built to the design of George Strong at the Hinkley Locomotive Works in 1888. The locomotive was not successful and was scrapped soon afterwards. The wheel arrangement was named after the second American tender locomotive class, built by the Baldwin Locomotive Works in 1894 for use on the Atlantic City line of the Philadelphia and Reading Railway.〔Poultney, E.C. (1952). ''British Express Locomotive Development, 1896-1948''. London: George Allen & Unwin. p. 40.〕 Baldwin's ideas on 4-4-2 tender locomotives were soon copied in the United Kingdom, initially by Henry Ivatt of the Great Northern Railway (GNR) with his GNR Class C1 "Klondyke Atlantic" of 1898. These were quickly followed by John Aspinall's Class 7, known as the "High-Flyer", for the Lancashire and Yorkshire Railway (L&YR). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「4-4-2 (locomotive)」の詳細全文を読む スポンサード リンク
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