LMS No. 10000 and 10001 were the first mainline diesel locomotives built in Great Britain. They were built in association with English Electric by the London, Midland and Scottish Railway at its Derby Works, using an English Electric 1,600 hp diesel engine, generator and electrics. Under British Railways, the locomotives became British Railways Class D16/1; they were initially operated primarily on mainline express passenger services on former LMS lines, both in single and in multiple. In 1953, they were transferred to the Southern Region for comparison with Bulleid's British Rail Class D16/2 diesel locomotives. Both locomotives were withdrawn and scrapped in the 1960s. Background and design Background In March 1947, the LMS announced its intention to operate main line passenger services using diesel traction: initial specifications were for a pair of 1,600 hp locomotives with a top speed of 100 mph, capable of hauling express services such as the Royal Scot. The company also announced it intended to use the same type singly on semi-fast suburban and medium weight freight services such as were hauled by 2-6-4T engines; English Electric engines were specified of similar design to that used on the company's diesel electric shunting locomotives. The LMS signed an agreement with English Electric to construct two 1600 hp locomotives: the mechanical parts were to be constructed at the LMS's Derby Works with George Ivatt responsible as the overall designer; electrical parts and diesel engine were to be supplied by English Electric. The bogies took an American pattern design, which was modified by Edward Fox and his team at Derby to create a smooth riding suspension. The welded bogie frame was derived from Fox's earlier design for Liverpool-Southport electric trains (later renumbered British Rail Class 502). Design The primary suspension consisted of equalising beams with coil springs; the equalising beams were located within the bogie 'sandwich type' side frame, whilst the secondary suspension utilised a two bolsters per bogie incorporating four transverse leaf springs. The locomotive weight was carried on four sliding elements on the bolster, with a center pivot used to transfer tractive forces. The locomotive body was a cowl unit design, consisting of structural longitudinal members, with cross stretchers forming the supports for the internal equipment including the engine-generator. The locomotive superstructure was mechanically separated from the load-bearing structures by pivots at either end of the body and incorporated roof doors for access to the diesel engine. The