AC16 Class

Total Number of Engines Built 20
First Engine Built 1943
Last Engine Built 1943
First Engine Written Off 1957
Last Engine Written Off 1969
Number of Engines in Class on the Books as at:
31/12/40 31/12/50 31/12/60 31/12/66 31/12/67 31/12/68 31/12/69
20 19 11 6 1
Number of Engines in Class in Service as at:
31/12/67 31/12/68 7/10/69


These twenty engines were obtained during World War 2 from USA 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 US Army Transportation Corps.

With sixteen inch diameter cylinders and eight coupled wheels they should have been classified C16 but to distinguish them from that existing class they were called American C16 i.e. AC16. The engines entered traffic with their US Army road numbers but had “A” appended to differentiate them from existing engines with the same numbers. Road numbers; 216A to 235A

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 original tenders rode poorly and resulted in a speed limit of 30m.p.h. 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.

In 1958, N°217A was fitted with a C16 type tender taken from a withdrawn locomotive. The previous restrictions were then lifted. All 19 members of the class then remaining in service had been similarly treated by 1963.

After being fitted with these tenders, seven of the class were attached to Alpha where they had a brief period of glory in the early 1960’s 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. 60 ton DEL took over the working in 1963.

The last engine in service was N°218A at Rockhampton. This engine is now at Zig Zag Railway Lithgow.

N° 221A was retained by QR and fitted with a new boiler and restored to working order in 2003. In the course of the overhaul it was fitted with a new tender and A6-ET brake equipment. Although the external appearance of the tender is similar to the original design, internally it is similar to a standard type with raised shovelling plate.


BLW – The Baldwin Locomotive Works Philadelphia USA

No images found in Gallery
Technical Details
 With original TenderWith C16 Tender
Wheel Arrangement2-8-22-8-2
Cylinders (diameter x stroke) ins.16 X 2416 X 24
Coupled Wheels diameter ins.4848
Rigid Wheel Base13' 6"13' 6"
Height over smoke stack11' 3"11' 3"
Axle Load10.29.2
Boiler Pressure - psi.185185
Heating Surface - tubes13711371
Heating Surface - Total sq. ft.17451745
Grate Area - sq. ft.27.727.7
Weight - Adhesive37.037.0
Weight - Engine53.453.4
Weight - Tender40.7536.7
Coal Capacity - tons6.58
Water Capacity - gallons41503000
Tractive Effort - lbs. (85%)2012820128
Factor of Adhesion4.124.12
Valve GearStephenson'sStephenson's
Westinghouse Pump9½ X 9½9½ X 9½
Brake Valve6-ET6-ET
Class Roster