Queensland BB18¼ class locomotive

Queensland BB18¼ class

BB18¼ No. 1079 passing through Enoggera station on a heritage tour

Type and origin Power type Steam Builder Vulcan Foundry, (35) Walkers Limited (20) Build date 1950–1958 Total produced 55

Specifications Configuration 4-6-2 UIC class 2′C1′ h Gauge 3 ft 6 in (1,067 mm) Length 60 ft 2 in (18.34 m) Height 12 ft 6 in (3.81 m) Axle load 12.1 long tons (13.6 short tons; 12.3 t) Loco weight 58.0 long tons (65.0 short tons; 58.9 t) Tender weight 43.2 long tons (48.4 short tons; 43.9 t) Total weight 101.2 long tons (113.3 short tons; 102.8 t) Fuel capacity 10.3 long tons (11.5 short tons; 10.5 t) Water cap 3,500 imp gal (16,000 l; 4,200 US gal) Firebox:  • Firegrate area 25 sq ft (2.3 m^2) Boiler pressure 170 lbf/in^2 (1,172 kPa) Heating surface 1,858 sq ft (172.6 m^2) Cylinder size 18.25 in × 24 in (464 mm × 610 mm) Valve gear Walschaerts

Performance figures Tractive effort 22,648 lbf (100.7 kN) Factor of adh 3.59

Career Operators Queensland Railways Class BB18¼ Numbers 1011–1045, 1070–1089

The BB18¼ class locomotive is a type of 4-6-2 engine or a likely Pacific type steam locomotive operated by the Queensland Railways. These types of engines operated on 1,067 mm (3 ft 6 in) gauge. The “B”, is used to identify the number of coupled wheels, being six coupled wheels for the BB18¼ class, followed by numerals indicating the cylinder diameter of 18¼ inches. These new locomotives were classed BB18¼, to distinguish them from their predecessor the B18¼ class. The BB18¼ 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 Westinghouse pump on fireman’s side, stainless steel rather than brass boiler bands, SCOA-P coupled wheels (rather than having traditional solid spokes the SCOA-P spoke is hollow, with a 'U' shaped cross section and are considerably lighter than a conventional spoked wheel) pressed steel sand box and a larger tender giving an increased coal and water capacity. 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.

History

Fifty-five BB18¼ class locomotives were built. The first batch of 35, numbered from 1011 to 1045, were built in 1950 by the Vulcan Foundry in Newton-le-Willows, Lancashire. The final batch of 20, numbered from 1070 to 1089, were built locally by Walkers Ltd. in the Queensland town of Maryborough between 1955 and 1958. No. 1089 was the last steam engine placed into service on a mainline Australian railway.^[1]

Throughout their careers, the BB18¼ class engines were used on a variety of trains, including long-distance passenger, mail and goods trains as well as suburban passenger services in the Brisbane metropolitan area. The class was withdrawn from service after 1967, with the last example removed upon the completion of dieselisation in 1970.^[1]

Preservation

Several examples of BB18¼ class engines have been preserved. Nos. 1079 and 1089 been retained by Queensland Rail as part of its Heritage Fleet, and are often used on main line tours.^[2] No. 1072 is in service at the Zig Zag heritage railway near Lithgow, New South Wales.^[3]

References

1. Queensland Railways Interest Group (24 February 2007). "BB18¼ Class". Retrieved 14 April 2009.
2. Workshops Rail Museum (1 March 2009). "Information Sheet: BB18¼ Class: No. 1079 and No. 1089" (PDF). Retrieved 14 April 2009.
3. Zig Zag Railway (2008). "About Zig Zag Railway: Locos & Carriages". Retrieved 14 April 2009.