Originally conceived as a cheaper, more reliable alternative to the Advanced Passenger Train in the early 1970s, the British Railways Board authorised the development of a prototype High Speed Diesel Train with two locomotives designated as Class 41. These aerodynamic power cars were constructed by British Railways Engineering Ltd at their Crewe Works and emerged in June and August 1972, fitted with Paxman Valenta 12RP200L engines, developing 2,250 hp.
When originally built at BREL’s Crewe Works, the InterCity 125 units were considered to be diesel multiple units and allocated as Class 253 to the Western Region and Class 254 for the Eastern Region. With the introduction of Trailer Guard Second (TGS) carriages, later power cars had no guard’s equipment installed and by 1987 most power cars were simply classified as Driving Motor (DM), although they still had luggage van space, retaining a window by the luggage door on each side.
In 1987, for trial purposes, eight of the Class 43s were converted for use as Driving Vehicles with the Class 89 and Class 91 locomotives. The power cars were fitted with buffers and Time Division Multiplex (TDM) equipment that allowed them to directly control the other locomotive. Following the delivery of British Rail’s Mk 4 coaching stock, the TDM equipment was removed and the power cars reverted to their normal duties, retaining their buffers. During the late 1990s, twenty five of the Class 43s were updated with Paxman 12VP185L engines in an attempt to reduce fuel consumption and emissions; however these proved to be less reliable in service than was hoped.
The HST fleet has seen many changes to the Train Operating Companies since privatisation in 1993, but Class 43 driven sets continue to operate across the rail network, despite being displaced from some East Coast and West Country routes by the arrival of Hitachi’s IEP 800 units.
Both units were built at Crewe, being delivered in early 1979; 43309 on 20 January and 43315 on 10 March, but initially the vehicles were formed into different sets and numbered 43109 and 43115 respectively. Both have shared similar naming conventions, as Yorkshire Evening Press and Yorkshire Cricket Academy, then as Scone Palace and Aberdeenshire, but both are currently unnamed in LNER service.