 In the North Island, the Tongariro Power Scheme was completed between 1964 and 1983.Under the Public Works Act 1876, the Department of Public Works was responsible for the operation of New Zealand's railway network from 1876 until 1880, when operations were transferred to the New Zealand Railways Department.This transfer did not end the PWD's railway operations, as it still operated railway lines when under construction, sometimes providing revenue services prior to the official transfer of the line to the Railways Department.