WAGR Pm and Pmr classes

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: ​  • Grate 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Western Australian Government Railways Numbers Pm701-Pm714, Pm716-Pm719, Pmr715, Pmr720-Pmr735 First run 4 January 1950 Withdrawn 1970-1972 Preserved Pm701, Pm706, Pmr720, Pmr721, Pmr729, Pmr735 Disposition 6 preserved, 29 scrapped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 All were withdrawn between 1970 and 1972.^[2][3][4]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

Pmr class locomotive no. 720 was the flagship of the Steamtown Peterborough Railway Preservation Society in the Mid North of South Australia. In May 1984, on an excursion trip, it traversed the iron floodway bridge 2 km south of Black Rock.

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

Builder's number Class Road number In service Withdrawn Notes 26545 Pm 701 4 January 1950 17 June 1971 Preserved at the Western Australian Rail Transport Museum[4] 26546 Pm 702 7 February 1950 14 August 1972 26547 Pm 703 16 February 1950 10 September 1970 26548 Pm 704 23 February 1950 14 August 1972 26549 Pm 705 2 March 1950 14 August 1972 26550 Pm 706 7 March 1950 17 June 1971 Preserved by Narrogin Apex Club / Hotham Valley Railway[6] 26551 Pm 707 15 March 1950 10 September 1970 26552 Pm 708 19 April 1950 14 August 1972 26553 Pm 709 24 April 1950 10 September 1970 26554 Pm 710 27 July 1950 17 June 1971 26555 Pm 711 23 June 1950 14 August 1972 26556 Pm 712 15 September 1950 14 August 1972 26557 Pm 713 28 September 1950 14 August 1972 26558 Pm 714 9 October 1950 14 August 1972 26559 Pmr 715 15 November 1950 14 August 1972 Built as Pmr class 26560 Pm 716 26 September 1950 14 August 1972 26561 Pm 717 16 August 1950 10 September 1970 26562 Pm 718 10 May 1950 14 August 1972 26563 Pm 719 9 May 1950 10 September 1970 26564 Pmr 720 29 June 1950 14 August 1972 Preserved at Steamtown Heritage Rail Centre, named Keith Smith previously operational[7] 26565 Pmr 721 24 July 1950 14 August 1972 Preserved at Northam railway station[8] 26566 Pmr 722 20 June 1950 14 August 1972 26567 Pmr 723 11 July 1950 14 August 1972 Fitted with Pr class dome cover, December 1967 26568 Pmr 724 29 June 1950 17 June 1971 26569 Pmr 725 5 July 1950 14 August 1972 26921 Pmr 726 5 July 1950 17 June 1971 26922 Pmr 727 8 July 1950 14 August 1972 26923 Pmr 728 19 July 1950 14 August 1972 26924 Pmr 729 27 July 1950 10 September 1970 Preserved at Coolgardie station[3] 26925 Pmr 730 4 August 1950 17 June 1971 26926 Pmr 731 8 August 1950 10 September 1970 26927 Pmr 732 18 August 1950 17 June 1971 26928 Pmr 733 6 September 1950 10 September 1970 Built as Pm, converted to Pmr 14 October 1955 26929 Pmr 734 6 September 1950 14 August 1972 26930 Pmr 735 31 August 1950 14 August 1972 Sold to TVW displayed at Bennett Brook Railway 1984-87, resold to Hotham Valley Railway, stored at Meelon[9][10]

See also

• Trains portal
• Western Australia portal

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