|
Under the Whyte notation a 2-8-8-4 is a steam locomotive with two leading wheels, two sets of eight driving wheels, and a four-wheel trailing truck. Other equivalent classifications are: *UIC classification: 1DD2 (also known as German classification and Italian classification) *French classification: 140+042 *Turkish classification: 45+46 *Swiss classification: 4/5+4/6 *Russian classification: 1-4-0+0-4-2 The equivalent UIC classification is, refined for Mallet locomotives, (1′D)D2′. Such a long locomotive must be an articulated locomotive, and all the examples produced were Mallets, with a joint in the frame between the first and second groups of driving wheels. The superstructure of the locomotive was attached to the rearmost set and the forward set and leading truck could swing laterally on curves. The type was generally named the ''Yellowstone'', a name given it by the first owner, the Northern Pacific Railway, whose lines run near Yellowstone National Park. Seventy-two Yellowstone type locomotives were built for four different US railroads. The 2-8-8-4 was a common arrangement for the largest steam locomotives. All Yellowstones had fairly small drivers of . For greater speeds, the Union Pacific Railroad chose a four-wheel leading truck and drivers for its Big Boy 4-8-8-4 class. Several classes of Yellowstone, especially the Duluth, Missabe and Iron Range's locomotives, are among the largest steam locomotives, with the exact ranking depending on the criteria used. ==Northern Pacific== The Northern Pacific Railway was the first railroad to order a 2-8-8-4. The first was built in 1928 by ALCO; it was the largest locomotive built until then, and it had the largest firebox ever applied to a steam locomotive, some in area. The purpose was to burn Rosebud coal, a cheap low-quality coal. That firebed was too large for the available draft and the fire burned poorly. The problem was mitigated by blocking off the first few feet of the grates. Baldwin built eleven more for the NP in 1930. None were saved. 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「2-8-8-4」の詳細全文を読む スポンサード リンク
|