The locomotives, numbered as NZMRC NO's 1–5, were responsible for running all trains over the Midland Railway between Reefton, Stillwater and Lake Brunner, as well as running NZMRC trains over the NZR line between Stillwater and Greymouth. Following the failure of the NZMRC and its takeover by the NZR, the locomotives were renumbered as LA 310–315. Now based at Greymouth, the engines remained in service until the first withdrawal began in 1920.
