Why is the 1522 called a Mountain?
The type designation of Mountain has nothing to do with where the engine was operated. It is a name given to a specific wheel arrangement. The 1522 has a 4 wheel pilot truck (under the cylinders), 8 drive wheels and a 2 wheel trailing truck under the boiler and cab. This 4-8-2 wheel arrangement became known as a Mountain wheel arrangement. Engines with one less drive axle would be 4-6-2 locomotives which are known as Pacifics.
