An engineering triumph on the North Island Main Trunk railway, where the line loops through a tunnel to to cross over itself. This geometry restricts the maximum gradient to 1 in 52, although there is a height change of 700 feet in 3.5 miles. The actual track length is 7 miles. The engineer was R W Holmes - the year 1898. To listen to the Audio Guide go to: DayOut Audio Guides to download it. See also DayOut Search
dayout