Power was delivered to the locomotive via overhead catenary, which 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. The pantograph was raised using pressurised air, power for which was provided via the battery-powered auxiliary air compressor.