4-4-0

4-4-0 (American)

Front of locomotive at left

1836 Patent drawing of the first 4-4-0 locomotive

Equivalent classifications UIC class 2′B French class 220 Turkish class 24 Swiss class 2/4 Russian class 2-2-0

First known tank engine version First use 1849 Country United Kingdom Locomotive GWR Bogie Class Railway South Devon Railway Builder Great Western Railway

First known tender engine version First use 1836 Country United States of America Railway Philadelphia, Germantown and Norristown Railway Designer Henry Roe Campbell Builder Philadelphia, Germantown and Norristown Railway Evolved from 4-2-0 Evolved to 4-6-0 Benefits Better tractive effort than the 4-2-0

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, 4-4-0 represents the arrangement of four leading wheels on two axles, usually in a leading bogie, four powered and coupled driving wheels on two axles, and no trailing wheels. Almost every major railroad that operated in North America in the first half of the 19th century owned and operated locomotives of this type. Due to the large number of the type that were produced and used in the United States, the 4-4-0 is most commonly known as the American type, but the type subsequently also became popular in the United Kingdom, where large numbers were produced.

The first use of the name American to describe locomotives of this wheel arrangement was made by Railroad Gazette in April 1872. Prior to that, this wheel arrangement was known as a standard or eight-wheeler. This locomotive type was so successful on railroads in the United States of America that many earlier 4-2-0 and 2-4-0 locomotives were rebuilt as 4-4-0s by the middle of the 19th century.

Several 4-4-0 tank locomotives were built, but the vast majority of locomotives of this wheel arrangement were tender engines.

Five years after new locomotive construction had begun at the West Point Foundry in the United States with the 0-4-0 Best Friend of Charleston in 1831, the first 4-4-0 locomotive was designed by Henry R. Campbell, at the time the chief engineer for the Philadelphia, Germantown and Norristown Railway. Campbell received a patent for the design in February 1836 and soon set to work building the first 4-4-0.