The GWR 633 Class were s designed by George Armstrong and built at the Wolverhampton railway works of the

Great Western Railway The Great Western Railway (GWR) was a British railway company that linked London with the southwest, west and West Midlands of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament on 31 August 1835 and ran ...

between November 1871 and April 1872. These were always southern division locomotives but over the years some were fitted to work the metropolitan lines and played a large role in the transportation of goods from Acton to Smithfield. Unusually, they had side (not saddle) tanks, and inside frames, with wheels of in diameter and a wheelbase of . The weight was 34 tons 12 cwt. There were twelve locomotives, numbered 633–644.Smith, Martin, ''Steam on the Underground'', Ian Allan Publishing 1994, p.22,

Modifications

Nos. 643 and 644 were fitted with condensing apparatus when built, for working on the

Metropolitan Railway The Metropolitan Railway (also known as the Met) was a passenger and goods railway that served London from 1863 to 1933, its main line heading north-west from the capital's financial heart in the City to what were to become the Middlesex su ...

Widened Lines and this was added to some others in the 1890s. These were the first size-coupled engines to be accepted for the widened lines. From 1887 they were reboilered with Dean pattern boilers and the wheels were enlarged by by means of thicker tyres. The class was reboilered again with Belpaire fireboxes (but not pannier tanks) between 1916 and 1925. 633, 634, and all the others fitted with condensers were sent to the London Division and were cabless to work through then metropolitan tunnels. The ones not fitted with condensers were fitted with a cab and allocated to South Wales.

Service

They were intended for the Southern Division of the GWR. The condenser-fitted engines worked in the London area, others at

Neath Neath (; cy, Castell-nedd) is a market town and Community (Wales), community situated in the Neath Port Talbot, Neath Port Talbot County Borough, Wales. The town had a population of 50,658 in 2011. The community of the parish of Neath had a po ...

South Wales South Wales ( cy, De Cymru) is a loosely defined region of Wales bordered by England to the east and mid Wales to the north. Generally considered to include the historic counties of Glamorgan and Monmouthshire, south Wales extends westwards ...

. Withdrawal took place in 1928-34.

References

Sources

* * {{GWR Locomotives 0633 GWR 0633 GWR 0633 Railway locomotives introduced in 1871 Standard gauge steam locomotives of Great Britain Mixed traffic locomotives