The NM class locomotives, 22 in number, were introduced in 1925 by the Commonwealth Railways in readiness for the extension of the Oodnadatta railway to Alice Springs. The design of the class was based on that of the Queensland Railways' C17 class. The NM class operated the Ghan and other services on the Central Australia Railway until replaced by diesel locomotives from 1954.

NM25 in Commonwealth Railways service

Technical specifications

Wheel arrangement 4-8-0
Weight 80 tons 19 cwt 82.2 t
Length 53 ft 0½ in 16.17 m
Tractive effort 19,200 lb 85.4 kN
Boiler pressure 160 psi 1103 kPa
Driving wheels 3 ft 9 in 1.14 m
Cylinders 17 x 22 in 430 x 560 mm
Valve gear Walshaerts
Grate area 18.5 ft² 1.7 m²
Coal capacity 6.5 tons 6.6 t
Water capacity 3,000 gal 13600 L

Representatives in the Pichi Richi Railway collection


For some years NM25 was the pilot engine based at Alice Springs (steam engines could go through deeper flood waters than diesels). It last ran about 1964. After storage in Port Augusta it was placed in Homestead Park at Port Augusta before the Pichi Richi Railway Preservation Society Inc. (PRRPS) obtained it in 1990. Restoration was carried out by PRRPS primarily with funds generously granted by the City of Port Augusta. Most of the restoration work was undertaken in Adelaide at Panorama Campus of Douglas Mawson Institute (TAFE SA). See the NM25 Restoration Project page for more information.

Builder Thompson Engineering and Pipe Co. Ltd
Entered service 14 December 1925
Builder’s number 51
Withdrawn from service  
Distance travelled in service  
Acquired by PRRPS 1991
Notes Last used on mainline 29 March 1964
PRRPS operational status Operational
NM25, Easter 2013 (Photo: Jeremy Browne)
NM25 and NSU52 (Photo: Jonathan Thompson)