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The
PB15 class were conceived as a passenger version of the earlier B15 class
4-6-0 freight locomotives dating from 1889, hence the ‘P’ prefix. A key
difference was the larger diameter driving wheels, being 4’ for the PB15
class as opposed to the original 3’ diameter of the B15 class. The
classification otherwise followed the Queensland Government Railways (QGR) naming
convention of ‘B’ for 6-coupled locomotives and ‘15’ to designate 15-inch
cylinder diameter. The first PB15 class locomotive entered service in 1899,
10 years after the B15 class. The PB15’s proved to be useful locomotives in
addition to their handsome, well-proportioned looks, and the class had grown
to 202 examples by 1912.
As
a testament to the utility of the PB15 design, the Ipswich Railway
Workshops constructed an additional unit in 1924 for the Aramac Shire
Tramway; this locomotive later passed into QGR stock in 1958 becoming
No.12. When the Queensland Railways administration of the early 1920’s
identified a need for additional mixed traffic locomotives for light lines,
the proven PB15 design was selected with a further 30 units built by
Walkers Limited, Maryborough between 1925 & 1926. These ‘1924 design’
PB15’s featured Walschaerts valve gear instead of the original Stephenson gear,
together with other modifications and modernisations.
The
PB15 class found extensive used on mail and passenger trains, lightly-laid
main lines (such as the Main Range route from Cairns to the Atherton
Tableland) and country branch lines, together with suburban passenger and
shunting turns. A number were withdrawn in 1942 and 1943, but the balance
lasted to the end of QGR steam operations, being withdrawn between 1967 and
1970.
PB15
No.732 entered service with Queensland Government Railways in March 1926
and was written off in March 1970 after a working life of 44 years. Following
retirement, No.732 was retained in operational condition for the QR
Heritage Fleet, although the more powerful BB18¼ and C17 locomotives have
predominated in heritage & tour train duties. I believe No.732 is currently
awaiting overhaul and is exhibited in the running shed area at The
Workshops railway museum, Ipswich.
Excellent
references for further information about the PB15 class are ‘Locomotives in
the Tropics - Volume 1 (Queensland Railways 1864 - 1910)’, which covers the
original Stephenson valve gear locos, and Volume 2 (Queensland Railways
1910 – 1958 and beyond) which covers the 1924 design / Walschaerts valve
gear locomotives. The Wikipedia page for the PB15 class also contains useful
technical data.
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