It branched from the Midland Line near its western terminus in Greymouth and ran up to Rewanui in the Paparoa Ranges.

[1] In comparison to the extension to Rewanui, this section was sedated, with the only significant engineering work being the Cobden Bridge across the Grey River at the start of the branch.

[2] This line was to be extremely steep: over its 5.4 kilometre length between Dunollie and the terminus, it would rise 163 metres with grades as severe as 1 in 26.

[1] Rewanui was inaccessible by road, thus a considerable number of passenger trains operated by the standards of New Zealand branch lines.

Although primarily for miners, the trains became minor local tourist attractions in the later years of the line due to the scenic nature of the route.

After extra brakes were fitted to the three WWs and WE 375, the Fell centre rail was removed in 1966 and only those four engines were permitted to run to Rewanui.

Occasional freight services continued to operate until May 1985, when the last train departed Rewanui with a load of coal from a nearby private mine.

The line was formally closed on 19 August 1985 from the junction with the Rapahoe Branch, which absorbed the six kilometres to Greymouth and remains in use.

A local committee exists to preserve the Rewanui area as a historic site, but a landslide in 1988 killed the caretaker and destroyed bridges and some buildings.