The Public Works Department conducted a number of surveys a concluded there were three possible routes: The final option was settled on, as the first two required significant tunnelling, then not feasible (Wellington had a population of just 22,000 in 1878).
[1] The government of Sir George Grey approved the construction of the line, which was included in the Public Works Estimates, reported to the House of Representatives on 27 August 1878.
The Commission reviewed the Wellington - Manawatu line in March 1880, and concluded that work should be abandoned.
[2] In response, John Plimmer, considered the "father of Wellington", proposed the formation of a private company to build and operate the line.
The company immediately let contracts for construction from Wellington to Wadestown, now part of the Johnsonville Line.
Meanwhile, rails were within two miles of Waikanae in the north by 25 September, with a service from Otaki connecting the two railheads.
The section was officially opened on 3 November 1886, when the last spike was driven at a public ceremony by the Governor of New Zealand, Sir William Jervois.