Kaimai Tunnel Kaimai Tunnel The Kaimai Tunnel is a railway tunnel through the Kaimai Range in the North Island of New Zealand. Since it was opened in 1978, it has held the title of longest tunnel, at 8.879 kilometres, in New Zealand, assuming this distinction from the previous title holder, the Rimutaka Tunnel. It is part of the Kaimai Deviation, which was constructed to bypass the old route of the East Coast Main Trunk Railway through the Karangahake Gorge (part of which has been preserved as the Goldfields Railway). The Kaimai Deviation is a 24 km line between Waharoa and Apata, including
Rimutaka Incline were the Tauwharenikau Route, Mr Sinclair’s Route, a coastal route and the Pakuratahi Route. While the government was conducting its surveys, Wellington Province Superintendent William Fitzherbert instructed his Provincial Engineer, Charles O’Neill, to investigate the possibility of a railway through the Rimutaka Valley (the route of the road between Featherston and Upper Hutt), with a tunnel through the dividing range. The survey was carried out between May and 21 July 1871, and O’Neill reported that a tunnel 130 chains (2.6 km) long would be required, with the line rising at 1 in 60 from the Pakuratahi to the tunnel then