Central Australian 4-8-0 Locomotives in Australia

Class Details by Steve Llanso of Sweat House Media

Class C17/NM (Locobase 3321)

Source is the Commonwealth Railways page -- [] . See also D[ennis] Rock Carling, 4-8-0 Tender Locomotives (New York: Drake Publishers, Inc, 1972), p. 81 and serial 253 on table XIII [13], pp.106-107.

Chris Drymalik explains that the CR took over CAR operation from South Australian and immediately found a need for more motive power. The tender offer had replies from 20 foreign manufacturers and three in Australia, of which Thomson Engineering and Pipe Co, Ltd had the best combination of price and adherence to the specifications. Obviously a very satisfactory design, these engines remained essentially unchanged except for the coal bunker, the capacity of which was increased several times. Retirements came in the mid-1950s.

The National Rail Museum site -- [] (14 February 2004) -- says the NM was "virtually a direct copy of the Cl7 class 4-8-0 of the Queensland Railways, which in itself was a development of the Cl6 class which had appeared back in 1903." It was part of the Commonwealth's policy of adopting only proven designs.

The museum adds that the class was the "mainstay of operations on the narrow gauge Central Australia line from Port Augusta to Alice Springs for nearly thirty years." Although designed to burn Newcastle coal, the locomotives at times had to burn all manner of fuel mixtures. Converting the class to oil burning in 1949 was short-lived, however.

Conversion to diesels in 1954 led to rapid retirement because most of the class was worn out.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID3321
RailroadCentral Australian
Number in Class22
Road Numbers
Number Built22
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)12.50 / 3.81
Engine Wheelbase (ft / m)21.50 / 6.55
Ratio of driving wheelbase to overall engine wheelbase 0.58
Overall Wheelbase (engine & tender) (ft / m)45 / 13.72
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)74,144 / 33,631
Engine Weight (lbs / kg)100,464 / 45,570
Tender Loaded Weight (lbs / kg)74,928 / 33,987
Total Engine and Tender Weight (lbs / kg)175,392 / 79,557
Tender Water Capacity (gals / ML)3600 / 13.64
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 8.80 / 8
Minimum weight of rail (calculated) (lb/yd / kg/m)31 / 15.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)45 / 1143
Boiler Pressure (psi / kPa)162.40 / 11.20
High Pressure Cylinders (dia x stroke) (in / mm)17" x 22" / 432x559
Tractive Effort (lbs / kg)19,504 / 8846.88
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.80
Heating Ability
Tubes (number - dia) (in / mm)
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)
Firebox Area (sq ft / m2)116 / 10.78
Grate Area (sq ft / m2)18.50 / 1.72
Evaporative Heating Surface (sq ft / m2)763 / 70.89
Superheating Surface (sq ft / m2)177 / 16.44
Combined Heating Surface (sq ft / m2)940 / 87.33
Evaporative Heating Surface/Cylinder Volume132.02
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation3004
Same as above plus superheater percentage3575
Same as above but substitute firebox area for grate area22,418
Power L16187
Power MT735.86

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