2-4-2

In the Whyte notation for the classification of steam locomotives by wheel arrangement, a 2-4-2 has two leading wheels, four driving wheels (two driving axles) and two trailing wheels. The type is sometimes named "Columbia" after an early locomotive of 2-4-2 arrangement.

Other equivalent classifications are:

UIC classification: 1B1 (also known as German classification and Italian classification)

French classification: 121

Turkish classification: 24

Swiss classification: 2/4

The equivalent UIC classification is 1'B1', if the leading and trailing wheels are in swivelling trucks.

While a number of 2-4-2 tender locomotives were built, larger types soon became dominant. The vast majority of 2-4-2s have been tank locomotives, designated 2-4-2T. The symmetrical arrangement suits a tank locomotive, which may travel in either direction.

See also

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