The Great Western Railway, had two classes of tender locomotives named after counties, the first class of two cylinder 4-4-0 tender locomotives, designed by George Jackson Churchward, were introduced in the 1900s to provide efficient motive power, for express passenger services on lines in the North Western area, of what was the Great Western, which were jointly operated, with the L & N W R from Shrewsbury to Birkenhead Woodside.

The 4-4-0 counties were in service on top link services until the early 1930s, when they were withdrawn and replaced by more modern motive power.

The 4-4-0 counties, were paralleled in design by the county 4-4-2 tanks, which operated suburban services in the London area and were also withdrawn in the early 1930s.

In 1945, the Great Western Introduced the County 4-6-0 tender locomotives, designed by F W Hawksworth, these two cylinder machines had a high pressure boiler, that was meant to give the same tractive effort as a Castle class, 4-6-0, four cylinder locomotive,

After modifications and boiler pressure reduction, the County class 4-6-0s, operated in express and semi fast train service, until the last members of the class were withdrawn in 1964.