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
Beaminster Tunnel a white cross which can still be seen "in situ". The tunnel reduced the road's gradient from 1-in-6 (17%) to 1-in-10 (10%) and shortened it by a mile (1.6 km), as well as lowering its maximum elevation by . At the time of its opening, only a handful of road tunnels had been built in Britain; it pre-dates the construction of the first railway tunnels, and it is now the only pre-railway road tunnel in the country still in use. The tunnel was formally opened on 29 June 1832 with enthusiastic celebrations including a 21-gun salute fired from the top