NZR EO class

The NZR EO class of 1923 was a class of electric locomotives built for the steep Otira to Arthurs Pass section of the Midland Line in New Zealand, and in particular for the Otira Tunnel, which at 8.5 km on a grade of 1 in 33 was too long and too steep for steam locomotives because smoke would build up in it and be difficult to clear. The English Electric Company of London won the contract to supply six electric locomotives, install the overhead contact wires and build a coal-fired power station at Otira, and five locomotives arrived on 10 April 1923, numbered E 2 to E 6. They were later reclassified EO to avoid confusion with the EC class. From 1942 three locomotives ran together as a set in multiple unit control with a two-man crew and a driver in each end cab, and with 14 timetabled trips a day this carried over 5,000 tons eastward daily. The class was replaced in April 1968 by the EA locomotives and all but one were scrapped, while EO 3 was preserved and operates on the Ferrymead Railway.