Under the Whyte notation system, a steam locomotive that has four coupled leading wheels, twelve coupled driving wheels, and one pair of trailing wheels.
Under the Whyte notation for the classification of steam locomotives, 4-12-2 represents the wheel arrangement of four leading wheels, twelve coupled driving wheels, and two trailing wheels. Other equivalent classifications are: AAR wheel arrangement: 2-F-1 UIC classification: 2′F1′ French classification: 261 Turkish classification: 69 Swiss classification: 6/9 This arrangement was named the Union Pacific type, after the only railroad to use it. Only one type of 4-12-2 was built: the Union Pacific Railroad's 9000-series locomotives, 88 of which were built by ALCO between 1926 and 1930. These locomotives were used to increase the speed of freight trains in flat country, and were fairly successful, but were maintenance nightmares, largely because of their use of an inside third cylinder driving the cranked second driving axle between the frames. There was no inside valve gear to worry about, however. ALCO had obtained permission to use the conjugated valve gear invented by Sir Nigel Gresley. This system used two hinged levers connected to the outer cylinder's valves to operate the inner cylinder's valve. The 9000 class locomotives were the largest to use Gresley gear.
The numerical value of 4-12-2 in Chaldean Numerology is: 0
The numerical value of 4-12-2 in Pythagorean Numerology is: 0
Images & Illustrations of 4-12-2
Find a translation for the 4-12-2 definition in other languages:
Select another language: