N.Z.R    EO (E)

photo: Colin Duthie

EO 2 enters the tunnel at Aurthur's Pass. October 1963

Electric traction was selected for the section between Arthur's Pass and Otira, because of the 8.55km tunnel. Arthur's Pass at an altitude of 737 meteres and Otira at 483 meteres, meant the tunnel had a gradient of 1 in 33, this was also the gradient from the tunnel entrance to Otira Station.
Smoke from Steam engines would make the assent intolerable, and diesel traction was not yet fully developed.
Six electric locomotives were ordered from English Electric (arriving 10th April 1923) numbered E1 which was a battery powered shunter. E2 to E6 had the Bo-Bo wheel arrangement, had a maximum speed of 64km/hr. They could pull 127 tons up the 1 in 33 grade at a maximum speed of 29km/hr.
From 1940 they were converted to single cabbed loco's also the cabs were closed in to exclude noise and draft for the crews.
From 1942 it became a regular practice to run the trains with 3 loco's hauling.