| Builder North British Locomotive Co No 411-450 WAGR Midland No 451-465 |
| coupled wheel diameter 4'6" |
| total weight 102t 5c |
| tractive effort 23,638lb |
| coal capacity 8 tons |
| water capacity 2800 gallons |
| number in service 25
P.508 entered service on 21 February, 1925 carrying the number P.448. It became P.508 on 5 June, 1947 & was condemned on 10 February, 1969. After a period of storage it was placed in the Rail Transport Museum on 8 October, 1971.
Pr Class |
| Builder WAGR Midland Workshops No 138-147 new construction Another 8 locomotives converted from P class |
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| coupled wheel diameter 4'6" | ||||
| total weight 102t 10c | ||||
| tractive effort 22,855lb | ||||
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| number in service 18 |
In 1922 a Royal Commission was appointed to enquire into the working of the
System of State Railways. In response to the Royal Commission the Railway
Department undertook a plan to regenerate the locomotive stock. Part of this
plan was for the construction of ten new superheated locomotives for heavy
( 60lb ) lines. These locomotives were the ten initial P Class pacifics.
Initially it had been proposed that construction be undertaken at Midland
Workshops. At this time ,however the workshops were fully employed with
locomotive overhauls and the superheating program for older locomotives.
The tender for construction was therefore awarded to the North British Locomotive
Company. The locomotives were placed in traffic between December 1924 and
February 1925 and were initially used on express traffic between Perth and
Kalgoorlie. The locomotives performed very favourably and were considerably
more economical on fuel and water than the F class of similar tractive effort.
As a result of the success of the P class arrangements were made for another
ten locomotives to be built at Midland workshops. The first of the new
locomotives entered service in February 1927. The Midland built locomotives
differed from the North British locomotives in that, to save money use was
made of tender underframes from scrapped R class locomotives. This resulted
in shorter tenders with a smaller coal and water capacity. A further five
locomotives were built in 1929 bringing the class to a total of twenty five
units.
From the onset of the great depression to the mid 1930's there was no new
locomotive construction. By 1936 the situation was desperate with many old
and obsolete locomotives on stock. Construction was therefore commenced on
ten improved P class locomotives. The modifications mainly consisted
of improvements to the valves and valve gear.The locomotives entered traffic
between January 1938 and June 1939. All ten locomotives were named after
Western Australian rivers. The class became known as the 'River Class' and
were eventually classified separately as the Pr class.
Following strengthening of bridges between Perth and Kalgoorlie in 1940
modifications were able to be made to the trailing wheel compensation which
resulted in an increased tractive effort of 25,855lb compared to the
original P class at 23638lb. The modification to increase the tractive effort
was a success. Eight P Class locomotives were therefore modified between
1941 and 1944 and reclassified as Pr class locomotives.
The P class locomotives were mainly allocated to passenger traffic on the
Southwest, Great Southern and Eastern railways while the Pr class was
predominantly allocated to passenger workings on the Eastern Goldfields line.
Most of both classes lasted until the end of the steam era on the WAGR.
