D6300 class introduction

     From the day they were ordered, similar to the D600 'Warship' class, the D6300 class of 'Baby Warships' were the locomotives the Western Region did not want. The WR required lightweight diesel - hydraulic engines of the German design, similar to the Krauss-Maffei V200 locomotives, whereas the British Transport Commission ordered the Bo-Bo class of an initial 6 to be built on the diesel - electric principles of a heavy frame. The BTCs vision was for the D6300 class to be the equivalent of the 1,000 hp diesel - electrics, Class 21, being built at the time by NBL, although some may argue that the BTC allowed the WR to have their own way and then watch as this new form of transmission failed miserably.

     These initial six members of the class were built by the North British Locomotive Company in Glasgow. A single MAN L12V18/21A engine giving 1,000 bhp at 1,445 rpm was coupled to a Voith L306r transmission. The Voith transmission was a tried and tested design as used in some of the Krauss - Maffei V200 locomotives, as well as the D600 'Warships.

     The underframe of the D6300s was built like a tank. Using ' I ' section beams and cross - members which were riveted and welded together and topped by a thick sheet steel floor with aluminium bodywork, bringing the total weight of each locomotive to 68 tons. The locomotives were supplied in standard BR green livery with a blue - grey line at the lower edge of the bodysides. One characteristic of the D6300s was in the use of spoked wheels.

     The first member of the class, number D6300, was delivered in January 1959, however fourteen months earlier in November 1957, the British Transport Commission ordered another 52 Class D6300's - the biggest single order for diesel locomotives at that time. The major difference between these locomotives and the initial batch of six was that the MAN L12V 18/21B engine of 1,100 hp at 1,530 rev/min was used. Additionally, the steam boiler was change from a Spanner Mk I type to a Clayton or a Stone-Vapor.


   In Use.

     Several small engine and transmission faults were noticed soon after the class were introduced. These components were then returned to NBL for repair due to a contractual agreement with the WR, however, this meant that locomotives would be out of service awaiting spares or repairs, especially as the two types of MAN engines were not inchangeable. In addition, the Spanner Mk1a train heating boilers fitted to all early diesels were very suspect. On average, engines were replaced after 8,000 hours in service ( there are 8,760 hours in one year ) while the locomotives generally clocked 40,000 miles annually.

     By 1961 the D6300 class became more and more reliable, however as a greater number of D800 'Warship' and then D7000 'Hymek' locomotives became available, the non - standard D6300s were assigned to less demanding duties. By 1968 a large number of engine and transmission spares were required, and with NBL no longer in business at this time, withdrawn locomotives donated their servicable parts to keep other members of the class in use.

     The first withdrawal from the class was number D6301 in December 1967 followed by another 26 members in 1968. There then followed a reprieve for two years for the class while a shortage of diesel-electric replacement locomotives was overcome and the last D6300s in service were numbers D6333, D6336, D6338 and D6339 which were withdrawn in January 1972. No members of this class were saved for preservation.