In the final push to close the gap in the North Island main trunk line, the railway had reached Taumarunui by 1904. To the south lay the imposing ascent onto the Waimarino plateau. After much difficulty, civil engineer Robert Holmes came up with a remarkable answer. He designed the Raurimu spiral, which included two tunnels, three horseshoe curves and a complete circle. This 1929 fold-out brochure, produced by the New Zealand Railways Publicity Branch, shows an aerial view of the spiral (centre panel). The side panels show the routes to the spiral from Auckland and Wellington.