User:8474tim/GWR 633 Class

Class of ten 0-6-0 tank locomotives built by George Armstrong at the Wolverhampton works of the Great Western Railway in 1871-2. Unusually, they had side (not saddle) tanks, and inside frames, with wheels of 4'6 1/2" diameter and a wheelbase of 15'6". They were intended for the Southern Division of the GWR; Nos. 643 and 644 were fitted with condensing apparatus when built, 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 by means of thicker tyres. The class was reboilered again with Belpaire fireboxes between 1916 and 1925. The condenser-fitted engines worked in the London area, others at Neath in South Wales. Withdrawal took place in 1928-34.