The New Zealand EA class (later reclassified as EO) of electric locomotives were used on the New Zealand rail network between 1968 and 1997 on the OtiraArthur's Pass section of the Midland line in the South Island, through the Otira Tunnel. Following reconditioning, three were used by KiwiRail's Tranz Metro in Wellington from 2008 to 2011 to top and tail Metlink suburban passenger trains as an interim measure before new rolling stock arrived. Four of the five locomotives were scrapped in 2013 with one being set aside for preservation. Introduction The class replaced the EO class of 1923, by then largely worn out, on Otira Tunnel duties in 1968. Like their predecessors, the EA class operated as a group of three, with two on standby at Otira. They were more powerful at 1,290 hp than the original EO class at 680 hp, and so could handle heavier trains. This was to prove useful when West Coast coal exports began in the late 1970s using trains of dedicated LC high side coal wagons. Standard operation of the EAs would see three in service at any one time hauling trains between Otira and Arthur's Pass. The other two locomotives would remain at the Otira electric locomotive depot, although any one of the two spare units could be sent to Addington Workshops for an overhaul as required. They were mostly used to haul freight trains, although they did occasionally haul passenger trains either on their own or in multiple with the diesel locomotive pulling the train. Originally the locomotives were classified as the EA class until the early 1980s when they were reclassified into the EO class. Withdrawal In 1987, demand for export coal necessitated the introduction of the CB class bogie hoppers on Ngakawau-Lyttelton export coal trains. These hoppers were heavier than the dedicated LC high side coal wagons previously used, and this led to a reduction in the amount that three EOs could haul through the tunnel. In 1988, NZR began experimenting with the use of diesel traction through the Otira Tunnel, with the reallocation of DX class diesel locomotives from the North Island, redeployed following the opening of the North Island Main Trunk electrification. The experiment was unsuccessful, but it was found by modifying the DX class locomotives with low-level intakes and modified drawgear (locomotives modified in this manner were later reclassified DXC) and adding giant extraction fans and tunnel