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
Wairarapa Line North Island Main Trunk section between Wellington and Palmerston North. The line originally included the famous Rimutaka Incline, which used the Fell mountain railway system to cross the Rimutaka Range between Upper Hutt and Featherston. In the mid-1950s, the line between Petone and Featherston was substantially realigned, with the line diverted to the east of the Hutt River between Petone and Haywards to serve new housing developments in northern Lower Hutt, and the construction of the Rimutaka Tunnel to replace the Rimutaka Incline. Part of the former route west of the Hutt River has been retained as the Melling Branch.