Transcontinental/Commonwealth 4-6-0 Locomotives in Australia

Class Details by Steve Llanso of Sweat House Media

Class G (Locobase 14229)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 49, pp. 241-270. Leon Oberg, Locomotives of Australia 1854-2007 (4th ed) (Rosenberg Publishing, 2007), pp. 166-167; "Locomotive for the Transcontinental Ry of Australia", Locomotive Magazine, Volume XXI [21] (15 January 1915), pp. 5-6; and Western Australia and South Australia Divisions, The Institution of Engineers, Australia, The Trans-Australian Railway-Nomination for Award as a National Engineering Landmark", archived at [], last accessed 16 July 2018. Works numbers were 41065-41068 in January 1914, 41220-41227 in April

See Locobase 4187 for an outline of how Baldwin came to be awarded contracts after the railway determined to go Australian. Like the home-grown Gs, the American ten-wheelers had flat-topped Belpaire fireboxes. The Baldwin specs run on for pages as every single component appears in meticulous descriptions. Should one ever wish to reproduce a G, the details should make it a dottle. And as the LM report says the Gs were "precisely similar" to the New South Wales P class, maybe a new P-class locomotive might be realizable.

However, as Drymalik dryly notes: "Purchasing engines overseas was rather controversial, even un-Australian and had only been allowed as a special dispensation." So the remaining ten were built in Australia. Those engines were not available until 1916, however, so the Baldwins bore the brunt of the early construction load. Locobase 4187 notes that the entire class initially suffered from sand in the axle boxes and hard mineral water.

The landmark nomination observed that during Trans-Australia construction, the G class had "frequent boiler failures" as did all of the engines using the unsuitable water. And, "as lengths to the railheads increased, those in service were worked to their limits, running averages of over 8,000 kilometres [4,969 miles] per month in 1916."

Most served through World War II and six were superheated and classified GA; see Locobase 4188.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID14229
Number in Class12
Road NumbersG5-G16
Number Built12
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.83 / 4.22
Engine Wheelbase (ft / m)25.75 / 7.85
Ratio of driving wheelbase to overall engine wheelbase 0.54
Overall Wheelbase (engine & tender) (ft / m)51.23 / 15.61
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)81,760 / 36,786
Engine Weight (lbs / kg)133,050 / 60,351
Tender Loaded Weight (lbs / kg)110,000 / 49,895
Total Engine and Tender Weight (lbs / kg)243,050 / 110,246
Tender Water Capacity (gals / ML)5400 / 20.45
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 7.50 / 7
Minimum weight of rail (calculated) (lb/yd / kg/m)45 / 22.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)60 / 1524
Boiler Pressure (psi / kPa)160 / 11
High Pressure Cylinders (dia x stroke) (in / mm)20" x 26" / 508x660
Tractive Effort (lbs / kg)23,573 / 10692.55
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.47
Heating Ability
Tubes (number - dia) (in / mm)252 - 1.875" / 48
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)13.85 / 4.22
Firebox Area (sq ft / m2)130 / 12.08
Grate Area (sq ft / m2)27 / 2.51
Evaporative Heating Surface (sq ft / m2)1824 / 169.45
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1824 / 169.45
Evaporative Heating Surface/Cylinder Volume192.94
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation4320
Same as above plus superheater percentage4320
Same as above but substitute firebox area for grate area20,800
Power L14187
Power MT338.70

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