New South Wales Z24 class locomotive

The Z24 class (formerly B55 class) is a two-cylinder, non-condensing, saturated 2-6-0 ‘ Mogul‘ type steam engine built by Dübs & Company for the New South Wales Government Railways of Australia.

New South Wales Z24 class
Class Z24 locomotive
Type and origin Power type Steam Builder Dübs & Company Build date 1889 Total produced 25
Specifications Configuration: ​  • Whyte 2-6-0  • UIC 1'Cn Gauge 4 ft 8+1⁄2 in (1,435 mm) standard gauge Driver dia. 4 ft 0 in (1,219 mm) Adhesive weight 84,000 lb (38,102 kg) Loco weight 104,000 lb (47,174 kg) Firebox: ​  • Grate area 21 sq ft (2.0 m2) Boiler pressure 140 psi (965 kPa) Heating surface 1,410 sq ft (131 m2) Superheater None Cylinders 2 outside Cylinder size 18 in × 26 in (457 mm × 660 mm)
Performance figures Tractive effort 20,855 lbf (92.77 kN) Factor of adh. 4.00
Career Operators New South Wales Government Railways Class B55, Z24 from 1924 Numbers 55-78, 388-393, 407-410 (2401-2425 from 1924) Retired 1929–1960 Disposition 4 preserved, 21 scrapped

Order

Following the success of the B205 class, in 1889 the New South Wales Government Railways ordered an additional 25 locomotives of a basically similar design from Dübs & Company. These locomotives had a deeper firebox, steel cab and weighed an extra nine tonnes. They were pooled with the B205 class in general working. The first locomotive entered traffic on 10 March 1891 and all were in service by August that year.^[1][2]

Operation

They took a generally unobtrusive part in main line goods traffic until displaced by the D50/D53/D55 class locomotives. They then moved on to branch lines until displaced by the C30T class locomotives which arrived in the mid-1920s.^[2]

Demise and preservation

As boiler renewals became due between 1929 and 1960, their numbers were depleted through either scrapping or disposal. Representatives found their way on to the private lines of such organisations as Bunnerong Power Station, Nepean Sand & Gravel at North Richmond and Hunter Valley collieries.^[2]

The last locomotive withdrawn was 2413 in November 1960, following an enthusiast tour to Richmond. It joined 2408 and 2414 at Bunnerong Power Station until 1975.^[1]

Preserved Z24 class locomotives

No.	Year	Current organisation	Location	Status	Ref
2408	1891	Dorrigo Steam Railway & Museum	Dorrigo	Stored
2413	1891	Junee Roundhouse Railway Museum	Junee Roundhouse Railway Museum	Static display
2414	1891	Dorrigo Steam Railway & Museum	Dorrigo	Stored
2419	1891	Transport Heritage NSW	Goulburn Rail Heritage Centre	static display	[3]