Rimutaka Tunnel The first shot was fired in 1948 when the Public Works Department started the tunnel with bores of at the western end and at the eastern end. A contract for completing the tunnel was let to a consortium of Morrison Knudsen Inc. and Downer and Company on 7 May 1951. The work commenced at the west end in July 1951 and at the east end in August. The contract was expected to be completed in four years, but the headings met on 20 April 1954 with the concrete lining finished a month later. New Zealand Railways took possession of the
Railway electrification in New Zealand Tunnel (1955) and the Kaimai Tunnel (1978). The Rimutaka Tunnel required an intermediate ventilation shaft. From 1967 diesel locomotives (D class) replaced electric locomotives (E class) on freight trains south of Paekakariki on the Kapiti Line after the track in some older tunnels was lowered, so diesels could run under the catenary into Wellington. On two existing electrified tunnels the electrified section was only a small part of the total line. Hence the Lyttelton Rail Tunnel was operated by diesel locomotives from 19 September 1970. The Otira Tunnel was long and steep, so for dieselisation from 1997 a door and