The GWR 633 Class were s designed by George Armstrong and built at the

Wolverhampton railway works Wolverhampton railway works was in the city of Wolverhampton in the county of Staffordshire, England. It was almost due north of the city centre, and is commemorated with a small display of level crossing gates and a plaque. Known as the Staff ...

of the Great Western Railway 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

Widened Lines The Widened Lines (also known as the City Widened Lines; formerly known as the Moorgate Line) is a double-track railway line forming part of the Thameslink route between St Pancras and within Central London. For most of their life the Widene ...

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 Dean may refer to: People * Dean (given name) * Dean (surname), a surname of Anglo-Saxon English origin * Dean (South Korean singer), a stage name for singer Kwon Hyuk * Dean Delannoit, a Belgian singer most known by the mononym Dean Titles * ...

pattern boilers and the wheels were enlarged by by means of thicker

tyres A tire (American English) or tyre (British English) is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface over which t ...

. The class was reboilered again with

Belpaire firebox The Belpaire firebox is a type of firebox used on steam locomotives. It was invented by Alfred Belpaire of Belgium in 1864. Today it generally refers to the shape of the outer shell of the firebox which is approximately flat at the top and sq ...

es (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 London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...

area, others at Neath in South Wales. 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