GM1-class A1A-A1A diesel-electric locomotive No.2

Commonwealth Railways

Standard Gauge


Class operators                                                   Commonwealth Railways/Australian National Railways

Condition                                                             Good

Provenance                                                         Commonwealth Railways & Australian National

Ownership                                                           National Railway Museum

Built by                                                                Clyde Engineering, Granville, NSW

Model                                                                  ML-1 (F class)

Number in class                                                  11

Number series                                                    GM1 - GM11

Entered service                                                  17th November 1951

Withdrawn                                                           6th March 1990

Entered the museum                                          2nd August 1991

Total Weight                                                       106 tons (107,696 kilograms)

Length (over coupling points)                             60’ 10’’

Wheel Arrangement                                           A1A-A1A

Engine type                                                       GM EMD 567B

Cylinders                                                            V16 (two stroke)

Bore & stroke                                                     8.5

Horsepower                                                       1625/1500 (1212/1120kW)

Traction Motors                                                 4x GM EMD-D 27

Gear Ratio                                                        58:19

Tractive Effort (starting)                                    41,440 lbs (184kN)

Tractive Effort (continuous)                              29,600 lbs at 15 mph (132kN at 24 km/h)

Fuel capacity                                                   1,500 gallons (6819 litres)

Maximum Speed                                              89 mph (143 km/h)

Maximum Axle Load                                         18.5 tons (18,796 kilograms)

Bogie centres                                                  10.36

Condemned                                                     31.03.1990

Class Builders                                                 Clyde Engineering, Granville, NSW

Designer                                                         Clyde Engineering, Granville, NSW

Height                                                             4.26

Mileage                                                           722,828 KM

Width                                                              2.97


Dieselisation of Australia’s major railway systems got off to a slow start because of a lack of local builders capable of manufacturing this type of locomotive. As a result, initial orders were placed overseas, and it wasn’t until 1951, when the Clyde Engineering Co., of Granville, NSW, gained the licence to build General Motors EMD locomotives for the Australian market. Thereafter dieselisation proceeded at a rapid rate, checked only by the funds available. Other diesel builders emerged but Clyde retained the largest share of the market.

Clyde had built steam locomotives since 1907 and was fortunate in being one of the few steam locomotive builders to successfully make the transition from steam to diesel production. The eleven GM-class locomotives ordered by the Commonwealth Railways (Australian National’s Predecessor) were the first diesel-electrics to leave the Granville plant and the forerunners of almost 1300 units built to date.

Based on General Motors-EMD’s F-7 model, the design for the local product required considerable modification to conform to Australian loading gauges and axle load restrictions. This job fell to Fred Shea who produced a machine with a car body both lower and longer than its US counterpart. The resulting A-7 (ML1) model was highly successful. Also, whereas the North American units were carried on four-wheel bogies, the GMs required six-wheel bogies to distribute the weight for the lighter track then in use, the traction motors being mounted on the outer axles. They were given road numbers 1 to 11.

GM1 underwent its road trials over New South Wales Railways’ tracks on 24th August 1951 and on its delivery run ran as far as Albury. At Bandiana it was transferred to broad-gauge bogies and hauled the rest of the way to Port Pirie where it was once more lifted onto its own bogies. It was placed in service on 20th September. GM2, the museum’s engine, entered traffic almost a month later on 17th November. All 11 were working by 8th July 1952.

Forty-seven GMs were built, though 12-47 were more powerful locomotives rated at 1750 h.p. and equipped with six traction motors. To identify each type, Nos. 1-11 became the GM1-class and Nos. 12-47 the GM12-class. The CR also identified them as F-class (four motor) and S-class (six motor) in their Working Timetables.

Originally they were restricted to the ‘Transcontinental’ route between Port Pirie and Kalgoorlie but, as the standard-gauge network expanded, they ranged farther afield. Eventually they were to work in all mainland states except Queensland.

The success of Fred Shea’s modifications to the original design can be gauged from the fact that variations of it were ordered by the Victorian Railways, New South Wales Railways and the North-Western Railway of Pakistan. All the GMs passed to the control of Australian National on 1st March 1978, and the first were not condemned until 1988. Most have had a lifespan well in excess of 30 years and only now are they being displaced by the more powerful DL and EL classes.

GM2 was set aside for the Museum and was placed there on 2.8.1991

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76 Lipson Street
Port Adelaide
South Australia  5015
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The National Railway Museum acknowledges the Kaurna people as the traditional owners and custodians of the Adelaide Plains. We honour and respect their ongoing cultural and spiritual connections to this country. We aim to respect the cultural heritage, customs and beliefs of all Indigenous people.

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