The 439 Class, nicknamed the Bicycle class because of its unusual appearance, was a series of six 2-4-0 mixed-traffic engines designed by Joseph Armstrong

Joseph Armstrong (engineer)

Joseph Armstrong was a British locomotive engineer and the second locomotive superintendent of the Great Western Railway...

 for the Great Western Railway

Great Western Railway

The Great Western Railway was a British railway company that linked London with the south-west and west of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament in 1835 and ran its first trains in 1838...

, and built at Swindon Works in 1868.

The locomotives

Numbered in the series 439-444, the running plate of these inside-framed locomotives was raised, without splashers, above each of the large (6'1") driving wheels, rather giving the impression of bicycle wheels and mudguards. The "Bicycles" worked at Northern Division sheds, running between Wolverhampton and Chester. Most of the class was renewed at Wolverhampton under George Armstrong

George Armstrong (engineer)

George Armstrong was in charge of standard gauge steam locomotives for the Great Western Railway at Stafford Road Works, Wolverhampton from 1864 to 1897...

in 1885/6; the renewals were more conventional in appearance, with large splashers, but the class's nickname stuck. At first the renewals also ran on the same routes as their predecessors, though later some were transferred further south.