New South Wales Z25 class locomotive

New South Wales Z25 class
2532 stands at Harden station with an enthusiasts’ special on 1 April 1962
Power type	Steam
Builder	Beyer, Peacock & Co.
Serial number	2073–2092, 2308–2337, 2547–2565
Build date	1881–1885
Total produced	70
Configuration	2-6-0
UIC classification	1'Cn
Gauge	4 ft 8 1⁄2 in (1,435 mm)
Driver diameter	4 ft 0 in (1.219 m)
Weight on drivers	77,000 lb (35 t)
Locomotive weight	95,000 lb (43 t)
Fuel type	Coal
Boiler pressure	140 psi (0.97 MPa)
Firegrate area	21 sq ft (2.0 m2)
Heating surface: Total	1,145 sq ft (106.4 m2)
Superheater type	None
Cylinders	Two, outside
Cylinder size	18.5 × 26 in (470 × 660 mm)
Tractive effort	22,060 lbf (98.1 kN)
Factor of adhesion	3.49
Career	New South Wales Government Railways
Class	B205; Z25 from 1924
Disposition	Two preserved, remainder scrapped.

The Z25 class was a class of 2-6-0 wheel arrangement steam locomotive built for and operated by the New South Wales Government Railways of Australia.

Design

In the late 1870s, only 11 of the 82 goods locomotives in service on the Southern and Western lines of the New South Wales Government Railways had a leading truck. The balance had a wheel arrangement of 0-6-0. To provide a more suitable locomotive for use over the 8 chain (161 m) radius curves of the Blue Mountains route, it was decided to incorporate a Bissell pony truck on an improved version of the A93-class (later (A)93; ultimately Z19).

Beyer, Peacock and Company prepared a design which was considered to be in advance of British contemporary practice. The first twenty 205-class (later (B)205, ultimately (Z)25) went into service in 1882.^[1]

Operation

The new engines were found to be more sluggish than the 93-class when getting away with a load, but pulled decidedly better when running tender first. Following tests on the Blue Mountains, Commissioner Goodchap recommended the installation of 50 ft. (15.25 m) turntables at Sydney, Bathurst and Goulburn which were required to turn the new locomotives.

At that time, there were thirty 93-class locomotives on order. As Locomotive Engineer W. Scott considered the new 205-class better suited to his requirements, the order was changed to 30 engines of that class, but with some minor improvements. This 30 went into traffic in the period 1883-1884, eight being allocated to the still isolated Northern lines.

Both batches were found to be prone to slipping and additional weight was necessary to be added to the driving wheels.

A further 20 locomotives arrived in 1885, five of which going to the Northern system. This last batch had cabs with steel cutaway sides – a slight improvement on the open cabs of the earlier batches.

In the late 1880s, this class was handling all of the difficult areas, being stationed at Sydney, Goulburn, Penrith, Bathurst, Newcastle, Murrurundi and Armidale. During holiday periods, these locomotives were pressed into service on excursion passenger trains.

None of the class was fitted with Westinghouse air brakes when built. Subsequent to 1901, all of the class were fitted with larger boilers which increased their weight and also increased the heating surface, matters identified as deficient in Thow’s Report of 1889^[2]. At the same time, wooden cabs replaced the open cabs of the earlier batches.

With the advent of the 2-8-0 wheel arrangement locomotives, main line work began to be assigned to these newer classes and the (B)205 class were relegated to lighter branch lines.

During the years of the Great Depression, many of these locomotives fell into derelict condition after becoming due for overhaul. Some were used on the testing of the Sydney Harbour Bridge in 1932.^[3]

Demise and Preservation

Following the introduction of the (C)30T-class from the mid-1920s, the death knell was sounded for the class. Representatives were sold to a number of private operators, including Emu Sand & Gravel, Prospect Quarry and collieries in the Hunter and Illawarra areas. Most others were scrapped, 58 during the 1930s.

Locomotive 2510 has been preserved by the New South Wales Rail Transport Museum and 2535 is at the Dorrigo Steam Railway and Museum.

References

1. ^ Grunbach, Alex (1989). A Compendium of New South Wales Steam Locomotives. Australian Railway Historical Society New South Wales Division. ISBN 0-909650-27-6. 
2. ^ Grant, Darryl S. (June 2005). "Two Colonies, Three Gauges - A Survey of the Locomotives of William Thow". Australian Railway History: pp.222–223. 
3. ^ Oberg, Leon (2007). Locomotives of Australia. Rosenberg Publishing Pty. Ltd.. ISBN 9781877058547. 

• Smith, J.D.H.. "New South Wales Government Railways steam locomotives". http://orion.math.iastate.edu/jdhsmith/term/slaunsw.htm. Retrieved 14 October 2008.