was always energised at 25,000 V AC. However, the main transformer, which was normally operated with the four windings in series, could be operated at 6.25 kV AC with the transformer windings in parallel. This voltage was intended to be used where limited clearances gave concern over use of the higher voltage arcing onto lineside structures, especially those made of cast iron. Since the clearances were found to be adequate, the lower voltage connections were locked out of use. A standardised Stone-Faiveley AMBR pantograph was adopted for the type, which was raised using pressurised air, the power for which was provided via the battery-powered auxiliary air compressor. Driver's cabs are provided at both ends of the locomotive. The cabs are of double-skin construction, with a sheet steel exterior around a steel frame, and an inner lining of plastic-faced plywood along with fibreglass mouldings for the ceiling. Asbestos was also applied for its thermal insulation and soundproofing properties; several electric heater units were also present each of the cabs. The driving controls, which conformed to BR's standard conventions of the era, were mounted on a sloped plastic-covered desk directly beneath the forward window; various instruments, light switches, indicators, and gauges lined the centre console. The master controller was to the right of the driver while the air brake controls were to the left. Operational history Upon their entry to service, the AL5 fleet was used to haul express trains on the then newly electrified West Coast Main Line, from Birmingham, to , Manchester Piccadilly, Liverpool, and later . By 1965, electrification had spread south to London Euston, allowing for services to be extended shortly thereafter. The first 30 Class 85 locomotives were built with germanium rectifiers in their power systems, after which the final 10 used silicon-based rectifiers instead. Silicon rectifiers were retrofitted across the whole fleet by the end of 1986. In 1968, the type was reclassified as Class 85 as a result of BR's introduction of the TOPS numbering system. From 1971 onwards, locomotives were progressively renumbered into the 85001–85040 range. Fourteen locomotives were later converted for freight-only use, numbered in the 85/1 subclass. These locomotives were restricted to . Accidents and incidents On 23 April 1983, 85027 caught fire while hauling a southbound intermodal train near Kings Langley. It was not returned to service. On 13 October 1985, 85001 caught fire while hauling the 16:15 Euston to Manchester