The Raurimu Spiral. It’s right up there in New Zealand rail lexicon and most people would tell you it’s one of the highlights of the Northern Explorer.
You will often find that man-made features such as viaducts spanning bottomless gorges can often only be fully appreciated standing some distance away watching from a viewing point. A panorama such as this sets the engineers’ accomplishments into context and a train passing across acts as the cherry on the top. Certainly those perspectives make the best photos. The Raurimu Spiral, however, is best experienced on board the Northern Explorer train as you are placed right into the visionary mind of engineer Robert Holmes. In 1898 when set with the task of overcoming a 200 metre height gradient with only 5km of distance and no other obvious way through, aside from a 20 km detour and nine huge viaducts, Holmes, without even the help of a high enough look-out to properly plan the route used his imagination to complete his blueprint, setting the course the train now travels.
Imagine as you ride the turns, bends and twists how Holmes would have travelled the route countless times in his mind, checking the gradients, the cuttings and curvature of the line. As you travel on you are drawn deeper into his engineering masterpiece, like being sucked into the eye of a tornado as the twists and turns get tighter this way and that, carriage wheels screaming, and the noise and light rushing on and off as the train climbs ever higher.
The Wikipedia entry refers to the spiral as an ‘Engineering Masterpiece’ primarily as not only did it solve the geographical challenge but to a greater extent, it used the natural contours of the land.
In traversing the spiral southbound we have Wikipedia to thank again for a concise commentary of the spiral which is situated just north of National Park. See if you can imagine the experience, but make sure you make full use of your senses!
“From the north, trains pass Raurimu before going round a [ascending] 200° bend to the left in a horseshoe curve, climbing above the track on which they have just travelled. Two sharp bends to the right follow, after which the line passes through two short tunnels, the Lower Spiral Tunnel (384 m) and the Upper Spiral Tunnel (96 m). Trains then complete a full circle, crossing over the Lower Spiral Tunnel through which they have just passed which is 23-metre (75 ft) below, before continuing towards Wellington. Two kilometres (1.2 mi) further on the line has two further sharp bends, to the right and then to the left.”