The origin of the G class design
In 1889 William Thow, the Locomotive Engineer of the South Australian Railways, became the New South Wales Government Railways (NSWGR) Locomotive Engineer. In February 1892 William Thow’s new design of steam locomotive was placed into service as the P6 class. This class was to eventually total 191 locomotives and in 1924 was reclassified as the C32 class.

The Commonwealth Railways (CR), was unique among Australian government railways in that it relied upon other railways, namely the New South Wales and Queensland Railways, for its steam locomotive designs. The G class were built to the NSWGR C32 design (but with an altered cab, larger tenders and automatic couplings) and were the first passenger locomotives built for the Transcontinental Railway.

Commonwealth Railways G class
Twenty-six G class locomotives were constructed for the CR between 1914 and 1917; the first four by Clyde Engineering, twelve by the Baldwin Locomotive Works USA, and ten by the Toowoomba Foundry. The G class spent 20 years hauling the Transcontinental Express between Port Augusta and Kalgoorlie, until displaced in 1938 by the larger and more powerful C class. Thereafter they were relegated to working the mixed trains between Port Pirie and Port Augusta, hauling occasional goods trains, shunting, and working troop trains during World War II.

No.1
G1 was built at the Clyde Engineering Works, New South Wales, in 1914, and was placed in service in March of that year. It was withdrawn from service in August 1945, but G1 was not sent to the scrap roads
at Port Augusta because of its historical significance, and was stored pending restoration. By the late 1960s this had still not eventuated and it was offered to the Museum by the then Commonwealth Railways Commissioner Mr K A Smith. It was gratefully accepted and placed on display in December 1969.

Built by: Clyde Engineering Works, New South Wales
Class operators: Commonwealth Railways
Entered service: 2 March 1914
Withdrawn from service: August 1945
Entered the museum: 17 Decemeber 1969
Number in class: 26

Standard gauge: Metric (1435 mm)
Length: Metric (18.10 m)
Total weight: Metric (107.93 tonnes)

Standard gauge: Imperial (4'8.5")
Length: Imperial (59'8")
Total weight: Imperial (106 tons 4 cwt)