The class N was introduced in a time when more and more American locomotives were built for the NZR, as the American designs were generally lighter and more flexible than the British ones. The N was a 2-6-2 that was intended for passenger and mail working. In 1885, six were delivered to the NZR by Baldwin. Two similar locomotives were built in 1891 for the Wellington and Manawatu Railway Company (WMR). The last four were again for the NZR and arrived in 1901. Later the WMR received four similar locomotives which were Vauclain compounds.

Originally, all were used on the North Island. In 1892, WMR No. 9 set a cape gauge speed record with 64.4 mph or 103.6 km/h. In World War I, the two WMR locomotives came to the Westland region of the South Island. All were withdrawn between 1926 and 1934. Although none were preserved, WMR No. 9 was one of the locomotives which had been buried in Bealey River. It was dug out between 2003 and 2006 and now, Steam Incorporated is restoring it.