The first was the E class of nine Double Fairlie steam locomotives of 1872-75; the second E class consisted of a Mallet compound made in 1906; and as both were no longer operated by the New Zealand Railways in 1923, the classification was free to be used for a third time when the small battery-electric locomotive was delivered.

This particular E class was ordered for service on the newly electrified Otira Tunnel section of the Midland line and was constructed in 1922.

Four DK 30 self ventilating traction motors were each of 44 hp (33 kW), for a total tractive effort of 6,200 lbf (28 kN) and a maximum speed of 10 mph (16 km/h).

[2] The locomotive 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.