Queensland AC16 class locomotive

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Queensland Railways AC16 class
Type and origin
Power typeSteam
BuilderBaldwin Locomotive Works
Serial number69451-69470
ModelUSATC S118 Class
Build date1943
Total produced20
 • Whyte2-8-2
Gauge1,067 mm (3 ft 6 in)
Leading dia.2 ft 2 in (660 mm)
Driver dia.4 ft 0 in (1,219 mm)
Trailing dia.2 ft 6 in (762 mm)
Length59 ft 5 12 in (18.12 m)
Adhesive weight80,000 lb (36,300 kg)
Loco weight119,000 lb (54,000 kg)
Fuel typeCoal
 • Firegrate area
27.7 sq ft (2.57 m2)
Boiler pressure185 lbf/in2 (1,276 kPa)
Heating surface:
 • Tubes and flues
1,256 sq ft (116.7 m2)
 • Firebox115 sq ft (10.7 m2)
 • Heating area347 sq ft (32.2 m2)
Cylinders2 outside
Cylinder size16 in × 24 in (406 mm × 610 mm)
Valve gearWalschaerts
Performance figures
Tractive effort20,128 lbf (89.53 kN)
OperatorsQueensland Railways
Preserved218A, 221A
Disposition2 preserved, 18 scrapped

The Queensland Railways AC16 class locomotive was a class of 2-8-2 steam locomotives operated by the Queensland Railways.


World War II and the occupation by Japanese forces of Pacific Islands and islands to the north of Australia saw Queensland placed under the threat of imminent attack. This placed a great strain on Queensland Railway’s resources in the movement of wartime supplies and troops.

A request was made in 1941 for further, new C17 class locomotives and the specifications were forwarded to the United States where the United States Army Transportation Corps (USATC) drew up plans for a 2-8-2 with specifications similar to a C17 class. The locomotives are also known is United States of America as USATC S118 Class steam locomotives. These locomotives were intended as a standard design for use on narrow gauge railways in other parts of the world as a wartime measure. Thus twenty engines obtained from the United States under Lend-Lease arrangements and later purchased. They were the only ones of their type to come to Australia out of a total of 741 similar engines built for USATC. They were unloaded in Sydney in 1943 and railed to Brisbane for assembly.[1][2][3][4]

Per Queensland Railway's classification system they were designated the AC16 class, C representing they had four driving axles, and the 16 the cylinder diameter in inches. Because the classification was already being used by an existing class they were designated American C16, i.e. AC16. The American steam locomotive earned it the nickname of Yank. The engines entered traffic with their US Army road numbers but had "A" appended to differentiate them from existing engines with the same numbers.[1][2]

The engines were supplied with conical profile tyres. These were altered to QR standard cylindrical profile and pressed one-sixteenth of an inch inwards on the wheels to reduce wear. In 1943 the decision was taken to alter the second and third coupled wheels to thin flanges. A number of other modifications were carried out over the years.

The engines were fitted with Walschaerts valve gear. The original tenders rode poorly and resulted in a speed limit of 30 mph being imposed with a prohibition on passenger train working. The axle load of these tenders also restricted the engines to main line usage. The floor level shovelling plate made the fireman’s work more difficult. One feature that did proved popular was the use of louvre coal boards and these subsequently became standard on all QR steam engines. The headlight mounted on the smokebox door proved to have advantages and was later adopted for some other classes.[2]

In 1958, No. 217A was fitted with a tender taken from a withdrawn C16 class locomotive. The previous restrictions were then lifted. All 19 members of the class then remaining in service had been similarly treated by 1963.[1][2]

After being fitted with these tenders, seven of the class was attached to Alpha where they had a brief period of glory in the early 1960s when they replaced the C17 Class hauling the air-conditioned Midlander between Alpha and Longreach. The American engines with a larger boiler capacity were able to reduce running times in the sections that contained many long banks. Diesel locomotive took over the working in 1963.


Two have been preserved:


  1. ^ a b c Armstrong, John (1994). Locomotives in the Tropics Volume 2. Brisbane: Australian Railway Historical Society. pp. 102–108. ISBN 9780909937263.
  2. ^ a b c d Turner, Jim (1997). Australian Steam Locomotives 1896-1958. Kenthurst: Kangaroo Press. p. 127. ISBN 086417778X.
  3. ^ Oberg, Leon (2010). Locomotives of Australia 1850s-2010. Dural: Rosenberg Publishing. pp. 224/225. ISBN 9781921719011.
  4. ^ Clark, Peter (2012). An Australian Locomotive Guide. Rosenberg Publishing. p. 73. ISBN 9781921719554.
  5. ^ AC16 218A Australian Steam
  6. ^ AC16 221A Australian Steam

Tourret, R. (1995). Allied Military Locomotives of the Second World War. Abingdon, Oxon: Tourret Publishing. ISBN 0-905878-06-X.