Little History:

The Union Pacific Railroad 9000 Class was a class of 88 steam locomotives, built by ALCO for the Union Pacific between 1926 and 1930. The Union Pacific 9000 class was the only class of steam locomotives with a 4-12-2 wheel arrangement ever to be built. Under the Whyte notation for the classification of steam locomotives, the locomotives had four leading wheels, twelve coupled driving wheels, and two trailing wheels. As the Union Pacific was the only operator of this wheel arrangement, it was often nicknamed the Union Pacific type.


Original Design.