British Railways Standard Class 4MT 2-6-4 Tank No. 80135 at Woodham Brothers scrapyard, Barry, Wales on 18th August 1966. Designed by Robert Riddles and built at Brighton Works, it entered traffic in April 1956. It was withdrawn from 84G Shrewsbury shed in July 1965, after spending most of its life based at 33A Plaistow shed for use on the London, Tilbury & Southend line.
The British Railways Standard Class 4 tank was a class of steam locomotive, one of the BR standard classes built during the 1950s. They were used primarily on commuter and outer suburban services. On the nationalisation of British Railways in 1948 the London Midland Region had a number of ex-London, Midland and Scottish Railway 2-6-4T and the Western Region a number of GWR Large Prairie 2-6-2T types. These tank engines were particularly suited to commuter and secondary services. However, particularly in Scotland and the Southern Region, the situation was not so good with large numbers of pre-grouping types struggling on.
On the decision to build the BR standard series of locomotives, a series of class four tank engines was ordered, based on the ex-LMS Fairburn 2-6-4T with some modifications. The lineage of the class could therefore be tracked through the LMS/BR Class 4 2-6-4T locomotives back to the Fowler design of 1927.
Design work was done at Brighton, the overall programme being overseen by R.A. Riddles. The principal modifications to the Fairburn design involved the reduction of their envelope to enable them to fit into the L1 loading gauge. To do this the tanks and cab were made more curved than the Fairburn design, the Fairburn having a straight-sided tank. The biggest mechanical change was a reduction in cylinder size, also to reduce cross-section, and a corresponding increase in boiler pressure to compensate. Other visible changes include the reintroduction of plating ahead of the cylinders.
130 of the class of 155 were built at Brighton, 15 (80000–80009, 80054–80058) at Derby Works and 10 (80106–80115) at Doncaster Works between 1951 and 1956. The first to emerge was 80010 from Brighton in 1951. Fifteen that were due to be constructed in 1957 were cancelled due to impending dieselisation, and the last five would have been too had they not been at an advanced stage of construction when the order came to cancel them.