Electric power was taken at 11 kV 50 Hz 3 phase from the Clarence Dock power station; the cables were laid through the Mersey Tunnel. The traction supply to the trains was at 650 V DC by third rail. Goods traffic continued to be steam hauled. route miles of railway were electrified. It had been proposed to electrify at 1,500 v dc overhead, but this was technically impossible through the Mersey Tunnel, so the third rail system was adopted. The position of the third rail was the same as on the Watford New Line electrification, and required the Mersey Railway system to alter its third rail from 22 inches outside the running rail to 16 inches, and to fit duplicate collector shoes to its rolling stock.