Freight trains off the Wairio Branch were largely industrial, and passengers were carried from Wairio to Invercargill from the line's opening until well into the 20th century. Due to decay of the old WR&CC line, the Railways Department stated that it would not permit its wagons to be used on the line after 31 December 1924, and thus the timing of the opening of the line to Ohai at the start of January 1925 proved to be fortuitous as it could carry traffic from the mines that had previously utilised the WR&CC route. Later in 1925 the Nightcaps Coal Company shut down operations and its railway extension was acquired by the Railways Department, which dismantled it in 1926.