During the deforestation of the
kauri forests in the Piha region, the logs had to be taken over a distance of to the sawmill in
Karekare, New Zealand, and the sawn timber had to be transported from there for another along the coast to
Whatipu, where it could be loaded onto ships. Before the railway was built, the wood was dragged by oxen or horses on the beach at low tide to Whatipu. Around 1906, Dr Raynor, a Canadian-born dentist working in Auckland, participated in William Stokes' timber extraction company, which had come into financial difficulties. Together they built a sawmill and a steam-powered forest railway. The wood was brought from the Piha Valley up to the steam-operated sawmill by a 1:4.5 (22%) steep incline and then to Karekare Beach by a 1:2.5 (40%) steep incline over a total distance of about . Over time, the forest railway was extended northwards to bring logs from the nearby Anawhata Valley to Piha. Later, an approximately long narrow-gauge line was built in the south, following the route of another previously built forest railway. It led from Karekare along the Tasman Sea to Whatipu, where a new jetty had been built at the entrance to Manukau Harbour on the side protected by Paratuate Island. For the narrow-gauge railway with a gauge of , steel rails with a weight of 7 to 14 kg/m (14 to 28 lbs/yd) were laid on wooden sleepers. Most of the railway line along the
Tasman Sea was of primitive quality. It crossed soft sandy beaches just a few metres above sea level and made its way along rocky outcrops and often past steep cliffs. Along the cliffs, where there was no natural route for the line, holes were drilled in the rock, in which the railway sleepers were fastened. Both the construction and the operation were affected by the notorious west coast weather: storms, torrential rain, wind and sand blowing across the tracks. The crossing of Karekare Beach itself proved difficult. The sand was hard in some areas and soft in others. Some up to high, primitive trestle bridges were built where the cliffs were interrupted at estuaries or bays. A tunnel was built, of which the
clearance outline was so narrow that the chimney of the steam locomotive had to be tilted into a horizontal position to allow it to pass. == Operation ==