BB18¼ Class

Total Number of Engines Built 55
First Engine Built 1950
Last Engine Built 1958
First Engine Written Off 1967
Last Engine Written Off 1970
Number of Engines in Class on the Books as at:
31/12/50 31/12/60 31/12/66 31/12/67 31/12/68 31/12/69 31/12/70
- 55 55 53 44 11 -
Number of Engines in Class in Service as at:
31/12/67 31/12/68 7/10/69
37 17 10

Notes

This design was an improvement on earlier successful B18¼ incorporating modern appliances. Some modifications to the original design were suggested by Vulcan Foundry and subsequently adopted. A number of features, including the mounting of WH pump on fireman’s side, stainless steel rather than brass boiler bands, SCOA-P coupled wheels and pressed steel sand box, distinguished these engines from the earlier B18¼ class. Engines constructed by Walkers Limited used electricity for the light on the rear of the tender, for side lamps and to illuminate the motion. All were fitted with Roller Bearings and chime whistles. The engines were painted green when introduced.

The first batch was constructed by Vulcan Foundry and the last 20 by Walkers Ltd, Maryborough. Contracts were let to both manufacturers in 1948 but Walkers did not deliver its first engine until 1955 due to shortages of materials. Delays in these deliveries resulted in the last of the order, N°1089, not entering service until March 1958 and thus becoming the last mainline steam locomotive to be built and placed in service in Australia. In fact Walkers had delivered some diesels to QR before completing this order.

Several members of the class that were overhauled in the final years were repainted black. In the 1950’s a “standard” boiler was designed to be suitable for both this class and B18¼ engines.

They proved to be a most successful design and were popular with crews. Initially they were used on mail trains, long distance passenger and goods trains and northside suburban services. The introduction of diesels saw them gradually relegated to lesser duties and ultimately cut short their careers.

Last engines in service were N°1012, 1030, 1037, 1039, 1070, 1073, 1081 and 1084 at Mackay and N°1088 at Ipswich.

Abbreviations

Vulcan – Vulcan Foundry, Newton-le-Willows, Lancs.,
Walkers – Walkers Limited, Engineers, Maryborough, Qld
ZZR – Zig Zag Railway Lithgow NSW

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Technical Details
Wheel Arrangement4-6-2
Cylinders (diameter x stroke) ins.18¼ X 24
Coupled Wheels diameter ins.51
Rigid Wheel Base10' 0"
Length60' 2"
Height over smoke stack12' 6"
Axle Load12.1
Boiler Pressure - psi.170
Heating Surface - tubes1418
Heating Surface - Total sq. ft.1858
Grate Area - sq. ft.25.0
Weight - Adhesive36.0
Weight - Engine58.0
Weight - Tender43.2
Coal Capacity - tons10.35
Water Capacity - gallons3500
Tractive Effort - lbs. (85%)22648 (85%)
Factor of Adhesion3.59
Valve GearWalschaert
Westinghouse Pump7-80"
Brake ValveA6-ET
Class Roster


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