The WAGR Pm and Pmr classes were two classes of 4-6-2 tender engine steam locomotives operated by the Western Australian Government Railways (WAGR) between 1950 and the early 1970s.

WAGR Pm and Pmr classes
Pm701 at the Western Australian Rail Transport Museum
Type and origin Power type Steam Builder North British Locomotive Company Serial number 26545-26569, 26921-26930 Build date 1949-1950 Total produced 35 (Pm: 19, Pmr: 16)
Specifications Configuration: ​  • Whyte 4-6-2 Gauge 3 ft 6 in (1,067 mm) Driver dia. 4 ft 6 in (1,372 mm) Length 63 ft 7.4 in (19.39 m) Width 8 ft 9.9 in (2.69 m) Height 12 ft 6 in (3.81 m) Total weight 109 long tons 0 cwt (244,200 lb or 110.7 t) Tender type 4-axle Fuel type Coal Water cap. 4,000 imp gal (18,000 l; 4,800 US gal) Tender cap. 8 long tons 0 cwt (17,900 lb or 8.1 t) Firebox:  • Firegrate area 35 sq ft (3.3 m2) Boiler pressure 175 lbf/in2 (1.21 MPa) Cylinder size 19 in × 26 in (483 mm × 660 mm) Valve gear Walschaerts
Performance figures Tractive effort 25,855 lbf (115.01 kN) Factor of adh. 3.6
Career Operators Western Australian Government Railways Numbers Pm701-Pm714, Pm716-Pm719, Pmr715, Pmr720-Pmr735 First run 4 January 1950 Withdrawn 1970-1972 Preserved Pm701, Pm706, Pmr720, Pmr721, Pmr729, Pmr735 Disposition 6 preserved, 29 scrapped

History

With the WAGR suffering from a shortage of locomotives and having a backlog of repairs deferred from World War II, authorisation was granted for the construction of 35 4-6-2 locomotives. Initially it was planned that Midland Railway Workshops build 10 with the balance built externally. However capacity constraints at Midland saw the order for the full 35 placed with the North British Locomotive Company, Glasgow.[1][2][3][4]

Nineteen were built as the Pm class with plain bearings on the coupled axles and roller bearings on the carrying axles. The other sixteen were built as the Pmr class with roller bearings on all axles. One Pm was later converted to a Pmr at Midland Railway Workshops.[2][3][4]

All entered service in 1950. Although intended to operate passenger services, their independently sprung driving wheels gave a rough ride meaning they could not maintain schedules, hence they were quickly relegated to fast freight trains on the Eastern Goldfields and Great Southern lines and associated branches. Later they were concentrated on the Great Southern and South Western lines. All were withdrawn between 1970 and 1972.[2][3][4]

Classes list

The numbers and periods in service of each member of the Pm and Pmr classes were as follows:[5]

See also

• Rail transport in Western Australia
• List of Western Australian locomotive classes

References

Notes

Bibliography

External links

Media related to WAGR Pm and Pmr classes at Wikimedia Commons