The early surveyors pointed out that Mount Ruapehu would demand much hard and heavy thinking on the part of the engineers. So it proved. The railway skirts the base of this peak, but has to make a stiff ascent in a short distance. The engineer did not resort to a zigzag to overcome the difficulty, but profited from the example of Hellwag on the St. Gotthard, who had to extricate that line from a similar tight corner. Recourse was made to a spiral. The result is that the railway emerges from a tunnel burrowed through a crest, and shortly after sweeps round in a graceful curve to cross the tunnel through the same obstruction; the railway overcomes the steep ascent by means of a stretch of corkscrew track. Near the base of the same mountain there is a deep gorge over which the line was forced to pass. From the point at which the track gained the brink it was about 800 feet to the opposite cliff edge, and the precipice delved down to nearly 300 feet. This is the famous Makatote Gorge, and the engineer decided to spring across the gap. The contract was secured by Messrs. J. & A. Anderson of Christchurch, and they lost no time in attacking the task. When they appeared on the scene there was no road to the site of the viaduct, and the railway was still 20 miles distant, so the prospect was not inviting. The sides of the mountain were covered with dense primeval jungle-like bush, which had to be hacked back to permit of investigations of the situation, and six months passed before the wagon road for the purposes of the railway was driven through the district. This constituted the only channel over which the requisite steel material could be transported. The constructional engineers concluded that the best means of meeting the situation was to erect a workshop on the spot where the necessary steel-work could be prepared. Electricity was generated to operate the various tools demanded. The rainfall averaged about 96 inches per year, and at times the insignificant stream flowing through the V-shaped fissure was nothing but a foaming torrent, sweeping everything away in its mad rush. The constructional engineers were faced with the erection of one tower springing from the bank of the waterway beneath to a height of 270 feet, while other towers of 249, 208, 175 and 110 feet in height respectively were demanded. The spans were of equal length, viz. 100 feet, flanked on either side by approaches, and the undertaking called for the use of about 1000 tons of steel.