In 1925, the English consultancy of Merz & McLellan was commissioned by then Minister of Railways, Gordon Coates, to report on electrifying the suburban networks in Auckland, Wellington, Christchurch and Dunedin.

Due to the locomotive changeover for such a short section being costly, and with drainage work going on in the vicinity of the Woolston sub-station, it was decided to reduce the losses made on this section and at the same time make it easier for the drainage work to proceed by withdrawing the electric locomotives.

The last locomotive of the class in service was EC 9, which hauled the last electric train over this line on 18 September 1970.

Class leader EC 7 along with EO 3 was donated to the Tramway Historical Society upon withdrawal.

In 1978, part of the Ferrymead line at Moorhouse station was fitted with overhead catenary and in 1980, some test runs were done with EC 7 at 600 V using the tramway power supply.

This is due to the lack of electrification on the Moorhouse station loop, which does not allow one locomotive to head the train on its own.