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4-4-4-4
A 4-4-4-4 steam locomotive, in the Whyte notation for describing locomotive wheel arrangements, has a four-wheel leading truck, two sets of four driving wheels, and a four-wheel trailing truck. While it would be possible to make an articulated locomotive of this arrangement, the only 4-4-4-4s ever built were duplex locomotives—with two sets of cylinders driving two sets of driven wheels in one rigid frame, essentially a 4-8-4 with divided drive. Usage The first locomotive built with this arrangement was the Baltimore and Ohio Railroad's sole class N-1 #5600 ''George H. Emerson'', constructed at the B&O's own Mount Clare Shops in May 1937. To reduce the fixed wheelbase, this locomotive had the two sets of cylinders at opposite ends, so that the rear pair were beside the firebox. This proved to be a poor design, as it restricted the firebox size and exposed the cylinders to dust and dirt, causing premature wear. The locomotive was not considered successful enough to duplica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pennsylvania Railroad Class S1
The Pennsylvania Railroad, PRR S1 class steam locomotive (nicknamed "The Big Engine") was a single experimental duplex locomotive of the Pennsylvania Railroad. It was designed to demonstrate the advantages of duplex drives espoused by Baldwin Chief Engineer Ralph P. Johnson. It was the longest and heaviest rigid frame reciprocating steam locomotive that was ever built. The streamliner, streamlined Art Deco styled shell of the locomotive was designed by Raymond Loewy. The S1 had a unique 6-4-4-6 wheel arrangement, meaning that it had two pairs of cylinder (engine), cylinders, each driving two pairs of driving wheels. To achieve stability at fast passenger train speeds (above 100 mph), articulation was not used. The S1 was completed on January 31, 1939, at Altoona shop, and was numbered 6100. At overall, engine and tender, the S1 was the longest reciprocating steam locomotive ever; it also had the heaviest tender (451,840 lb / 205 tonnes), highest tractive effort () of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
