Pr Class Steam Locomotive
Pr 521 'Ashburton'
| Builders: North British Locomotive Co WAGR Midland Workshops No 138-147 Another 8 locomotives converted from P class | ||||||||
| Coupled wheel diameter 4' 6" | ||||||||
| Total weight 102 tons 10 cwt | ||||||||
| Tractive effort 22,855 lbs | ||||||||
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| Total number in service 25 |
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; the 'r' for 're-balanced'.
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. Following the introduction of the X/XA diesels in 1954 the Pr class were transferred to freight service, mainly in the Great Southern district. Pr 521 entered service on 28 January 1938 as the class leader Pr 138 and named 'Ashburton'. It was re-numbered to Pr 521 on 17 may 1946. During the coal shortages in the late 1940's, Pr 521 was temporarily converted to burn oil from December 1947-October 1948. After many years at Midland Junction and Narrogin depots, Pr 521 became the last of its class to be withdrawn in May 1969. It was placed in storage at Northam and condemned on 10 September 1970, and delivered to the Rail Museum on 8 October 1971.