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A discussion about the WAGR O-class
2-8-0T+T locomotives would not be complete without considering the earlier
heavy freight K-class, and the contemporary suburban passenger N-class. The
K-class 2-8-4T’s had been introduced in 1893 and proved successful as a
powerful type capable of running on 60 lb rails, with the weight of water
tanks over the diving wheels providing much-needed adhesion on steeply
graded main lines. The O-class 2-8-0T+T were conceived as a heavy freight
locomotive derived from the K-class, but available for use on the lighter
45lb rails of the Eastern Goldfields Railway, although the two classes
differed in principle dimensions.
The first O-class locos were delivered in
1896 in response to rapid rail traffic growth in the WA gold boom years,
with the pattern engines built by Scottish builder Neilson & Co. The
O-class were provided with saturated steam boilers, slide valves and small
3’ diameter driving wheels; it seems the class were noted for slow running.
An interesting feature was the provision of modest water tanks in addition
to the tender supply. It seems these water tanks were primarily to assist
with adhesive weight over the driving wheels rather than range extension
because the tanks were separately piped to the injectors and were usually
kept full and unused. This hybrid tender + tank design perhaps further
illustrates their original K-class lineage.
O-class usefulness diminished with the
arrival of F-class 4-8-0 freight locos from 1902 and withdrawals started as
early as 1907, with 10 class members subsequently donating cylinders and
other parts to the construction of additional N-class 4-4-4T suburban tank
locomotives. Despite these conversions and many O-class having been stored
for some years, by 1909 the WAGR administration saw the need for additional
light-lines power due to an expected heavy wheat harvest and the growing
network of lightly laid rural lines. In response, 10 improved ‘Oa’ class
locomotives were constructed at Midland Workshops, using some remaining
parts from the locos converted to N-class, but with new frames and
increased diameter driving wheels. These 10 locos were known as the Oa
class.
Superheating was applied to some O and
Oa-class members, but ultimately removed at later overhauls – presumably
due to the usual issue of hotter, drier steam causing excessive wear on the
slide valves.
The O and Oa class provided useful in
light-lines and shunting duties, probably seeing less use between harvests,
until their ranks thinned with further withdrawals from 1940. They were
finally displaced by modern W-class 4-8-2 locos during the 1950’s, with the
final class members retired in 1961.
Preserved loco O 218 entered service on 11
October 1898, and during its service life it ran some 1.2 million km. It
was officially withdrawn on 25 July 1961 but then found use in steam
cleaning duties at Northam Loco Depot, surviving long enough to be saved to
represent the class in preservation. It was transferred to the care of the
Australian Railway Historical Society (WA Division) and entered their
Bassendean museum on 2 December 1971. Alas no Oa-class locos survived.
In April 2015, O
218 was transferred to the rural town of Walkaway on a 5-year loan and
placed on display at the Walkaway Station Museum, centred on the historic
Midland Railway station and good shed. The City of Greater Geraldton
provided funding for a 2-road display shed alongside the former loading
dock, where O 218 is now presented together with Midland Railway General
Manager’s Saloon Carriage KA17, fettlers trikes and other memorabilia. Also
found at the Walkaway Station Museum is the sole surviving Midland Railway
steam locomotive B 6, thus the Walkaway Station Museum
now houses two of the more significant and unique steam locomotives
preserved in Western Australia.
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