7714, GWR 5700 Class 0-6-0 pannier tank
Photographed at Bridgnorth on 8 March 2009 during the Severn Valley Railway Steam Gala.
863 of these pannier tank locomotives were built between 1929 and 1950, making them the second most-produced British class of steam locomotive.
The GWR had favoured pannier tank locomotives since 1911 when they had started rebuilding saddle tank locomotives built between 1870 and 1905 into this style. By 1929 these older locomotives were in need of replacement.
The first 5700s were almost identical in appearance to several of the older converted locos (e.g. classes 645, 1701, 1854, 2721) and had round spectacles (windows) in the cab front, but those built after 1933 from 8750-onwards had rectangular windows and a slightly different cab profile virtually identical to the style introduced with the GWR 5400 Class in 1931.
A number of 5700s were sold for further use after being withdrawn by British Railways. The National Coal Board bought a few (at least six) but the best known are those bought by London Transport.
Eleven 5700s were bought by London Transport and used on the London underground network starting in 1956. They replaced older LT steam locomotives on permanent way trains and were never used on normal passenger services. Main line running included trips between depots, to Acton Works and runs out to Croxley Tip, near Watford. A further two locomotives were later bought to replace classmates that were withdrawn in need of major repairs.
Picture added on 13 March 2009