GWR 633 Class

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GWR 633 Class
Type and origin
Power type Steam
Designer George Armstrong
Builder GWR Wolverhampton Works
 • Whyte 0-6-0T
Gauge 4 ft 8 12 in (1,435 mm) standard gauge
Driver dia. 4 ft 6 12 in (1,384 mm)
Wheelbase 15 ft 6 in (4.72 m)
Loco weight 14 long tons 12 cwt (14.8 t; 16.4 short tons)
Cylinder size 16 in × 24 in (406 mm × 610 mm) dia × stroke
Operators Great Western Railway
Class 633

The GWR 633 Class were 0-6-0 tank locomotives designed by George Armstrong and built at the Wolverhampton railway works of the Great Western Railway in 1871-2. Unusually, they had side (not saddle) tanks, and inside frames, with wheels of 4 ft 6 12 in (1,384 mm) in diameter and a wheelbase of 15 ft 6 in (4.72 m). The weight was 34 tons 12 cwt. There were twelve locomotives, numbered 633-644.[1]


Nos. 643 and 644 were fitted with condensing apparatus when built, for working on the Metropolitan Railway Widened Lines and this was added to some others in the 1890s. From 1887 they were reboilered with Dean pattern boilers and the wheels were enlarged by one inch (25 mm) by means of thicker tyres. The class was reboilered again with Belpaire fireboxs (but not pannier tanks) between 1916 and 1925.


They were intended for the Southern Division of the GWR. The condenser-fitted engines worked in the London area, others at Neath in South Wales. Withdrawal took place in 1928-34.[2]


  1. ^ Smith, Martin, Steam on the Underground, Ian Allan Publishing 1994, p.22, ISBN 0-7110-2282-8
  2. ^ le Fleming 1958, pp. E33-E35.


  • le Fleming, H. M. (1958). The Locomotives of the Great Western Railway, part five: Six-coupled Tank Engines. Kenilworth: RCTS.