This particular E class was ordered for service on the newly electrified Otira Tunnel section of the Midland line and was constructed in 1922. In April 1923, English Electric delivered an order of six locomotives: five EO class mainline locomotives that collected electricity from overhead wires, and a sixth small battery electric locomotive for maintenance duties. It was classified as E 1, had a wheel arrangement of Bo-Bo-2 under the UIC classification system, and worked for the rest of the 1920s.
Clearly not an exceptional performer, it was written off around 1930 due to the costs involved in maintaining its batteries. Instructions were issued for any equipment that could not be re-used elsewhere from the locomotive to be dumped locally. E 1's cab can still be found alongside the track just south of Otira. The runner wagon for E 1 was stripped of its batteries and found use at Addington Workshops as a general purpose wagon around the complex. E 1 consisted of a locomotive and a tender, each carrying 216 "Ironclad Exide" cells with a total capacity of 167,000 ampere hours at 400 volts. Four DK 30 self ventillating traction motors each of 44 hp (33 kW) were used for a total tractive effort of 6,200 lbf (28 kN) and a maximum speed of 10 mph (16 km/h). It could haul 40 long tons (45 short tons; 41 t) at 8.5 mph (13.7 km/h) on the gradient of 1 in 33 (3 %) that prevailed between Arthurs Pass and Otira.