4-8-2

Under the Whyte notation for the classification of steam locomotives, 4-8-2 represents the wheel arrangement of four leading wheels, eight powered and coupled driving wheels and two trailing wheels. This type of steam locomotive is commonly known as the Mountain type.

Other equivalent classifications are:

Overview

The tank and tender locomotive versions of the 4-8-2 Mountain wheel arrangement both originated in the Colony of Natal in South Africa.

In 1888 the Natal Government Railways (NGR) placed the first five of its eventual one hundred Class D 4-8-2T tank locomotives in service. The locomotive was designed by William Milne, the Locomotive Superintendent of the NGR from 1877 to 1896, and was built by Dübs and Company. This was the first known use of the 4-8-2 wheel arrangement in the world.