2-4-0WT

2-4-0 (Porter)

Front of locomotive at left

LSWR 0298 Class or Beattie Well Tank

Equivalent classifications UIC class 1B French class 120 Turkish class 23 Swiss class 2/3 Russian class 1-2-0

First known tender engine version First use c. 1830s-1840s Country United Kingdom Evolved from 2-2-0 & 2-2-2 Benefits Better adhesion with coupled wheels

Under the Whyte notation for the classification of steam locomotives, 2-4-0 represents the wheel arrangement of two leading wheels on one axle, four powered and coupled driving wheels on two axles and no trailing wheels. The wheel arrangement is known as a Porter.

The notation 2-4-0T indicates a tank locomotive of this wheel arrangement on which its water and fuel is carried on board the engine itself, rather than in an attached tender.

The 2-4-0 configuration was developed in the United Kingdom in the late 1830s or early 1840s as an enlargement of the 2-2-0 and 2-2-2 types, with the additional pair of coupled wheels giving better adhesion. The type was initially designed for freight haulage. One of the earliest examples was the broad-gauge GWR Leo Class, designed by Daniel Gooch and built during 1841 and 1842 by R and W Hawthorn and Company, Fenton, Murray and Jackson, and Rothwell and Company. Because of its popularity for a period with English railways, noted railway author C. Hamilton Ellis considered the 2-4-0 designation to have the nickname (under the Whyte notation) of Old English.

During 1846-47, Alexander Allan of the newly established London and North Western Railway (LNWR) created the Crewe type of locomotive, with a 2-2-2 wheel arrangement for passenger classes and 2-4-0 for freight. During the 1850s and 1860s these designs were widely copied by other railways, both in the United Kingdom and overseas.