New South Wales Z23 class locomotive

The Z23 class (formerly O.446 class) was a class of steam locomotives built in 1891 for the New South Wales Government Railways in Australia.[2][3][4]

New South Wales Z23 Class
NSWGR O.446 Class Locomotive.jpg
O.446 Class Locomotive
Type and origin
Power typeSteam
BuilderBaldwin Locomotive Works[1]
Total produced12[1]
 • Whyte4-6-0[1]
Gauge4 ft 8+12 in (1,435 mm) standard gauge[1]
Driver dia.5 ft 1 in (1,549 mm)[1]
Total weight90.37 long tons
(101.21 short tons; 91.82 t)[1]
 • Firegrate area
27.7 sq ft (2.57 m2)[1]
Boiler pressure160 psi (1,100 kPa) [1]
Cylinder size21 in × 24 in
(533 mm × 610 mm)[1]
Performance figures
Tractive effort22,209 lbf (98.79 kN)[1]
DispositionAll scrapped

Royal CommissionEdit

Although this may have been the result of a contemporary anti-American bias, these locomotives were said to be too heavy and too wide at the cylinders, and were the subject of a Royal Commission.[5]


2305 was the first withdrawn in May 1933. By 1941, only six were left, with the last, 2304, being withdrawn in September 1946.[1] None has survived onto preservation.

See alsoEdit


  1. ^ a b c d e f g h i j k Oberg, Leon (1975). Locomotives of Australia. p. 73. ISBN 0 589 07173 4.
  2. ^ Preston, Ron G (1984). Tender into Tank. Sydney: New South Wales Rail Transport Museum. pp. 11–57. ISBN 0 909862 18 4.
  3. ^ Grunbach, Alex (1989). A Compendium of New South Wales Steam Locomotives. Sydney: Australian Railway Historical Society, NSW Division. pp. 41–45. ISBN 0 909650 27 6.
  4. ^ New South Wales Railways 1855-1955. Published by Department of Railways
  5. ^ "BALDWIN ENGINE COMMISSION". The Sydney Morning Herald. National Library of Australia. 26 May 1892. p. 6. Retrieved 27 October 2014.