2-4-2T

2-4-2 (Columbia)

Raahe track 2-4-2T, Finland

Equivalent classifications UIC class 1B1, 1'B1' French class 121 Turkish class 24 Swiss class 2/4 Russian class 1-2-1

First known tank engine version First use 1863 Country United Kingdom Locomotive No. 21 White Raven Railway St Helens Railway Designer James Cross Builder Sutton Works

First known tender engine version First use 1877 Country New Zealand Locomotive K class Railway New Zealand Railways Builder Rogers Locomotive Works

Under the Whyte notation for the classification of steam locomotives, 2-4-2 represents the wheel arrangement of two leading wheels on one axle, four powered and coupled driving wheels on two axles and two trailing wheels on one axle. The type is sometimes named Columbia after a Baldwin 2-4-2 locomotive was showcased at the 1893 World's Columbian Exposition held at Chicago, Illinois.

The wheel arrangement was widely used on passenger tank locomotives during the last three decades of the nineteenth and the first decade of the twentieth centuries. The vast majority of 2-4-2 locomotives were tank engines, designated 2-4-2T. The symmetrical wheel arrangement was well suited for a tank locomotive that is used to work in either direction.

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

While a number of 2-4-2 tender locomotives were built, larger tender locomotive types soon became dominant.

In 1899, the Walvis Bay Railway in the British territory of Walvis Bay, a Cape of Good Hope exclave in Deutsch-Südwest-Afrika (German South West Africa), placed a single tank locomotive in service. The engine, named Hope and built by Kerr, Stuart and Company, remained in service until 1904 when operations on the railway were suspended. The line was abandoned in 1905, partly as a result of being buried by a sandstorm.

A 2-4-2 tank locomotive, built by Baldwin Locomotive Works in 1899 and used on the private Raahe track in Finland, was later bought by the Finnish State Railways.