BR Standard Class 6

BR Standard Class 6[1]
72001 Clan Cameron
Type and origin Power type Steam Designer Robert Riddles at BR Derby Builder BR Crewe Works Build date December 1951 – March 1952 Total produced 10
Specifications Configuration: ​  • Whyte 4-6-2  • UIC 2′C1′ h2 Gauge 4 ft 8+1⁄2 in (1,435 mm) standard gauge Leading dia. 3 ft 4 in (1,016 mm) Driver dia. 6 ft 2 in (1,880 mm) Trailing dia. 3 ft 3+1⁄2 in (1,003 mm) Length 68 ft 9 in (20.96 m) Width 8 ft 8+3⁄4 in (2.66 m) Height 13 ft 0+1⁄2 in (3.98 m) Axle load 19 long tons (19 t; 21 short tons) Adhesive weight 56.9 long tons (57.8 t; 63.7 short tons) Loco weight 88.5 long tons (89.9 t; 99.1 short tons) Tender weight 49.15 long tons (49.94 t; 55.05 short tons) Tender type BR1 Fuel type Coal Fuel capacity 7 long tons (7.1 t; 7.8 short tons) Water cap. 4,250 imp gal (19,300 L; 5,100 US gal) Firebox: ​  • Grate area 36 sq ft (3.3 m2) Boiler BR1 Boiler pressure 225 psi (1,550 kPa) Heating surface: ​  • Firebox 195 sq ft (18.1 m2)  • Tubes and flues 1,878 sq ft (174.5 m2) Superheater: ​  • Heating area 592 sq ft (55.0 m2) Cylinders Two, outside Cylinder size 19.5 in × 28 in (495 mm × 711 mm)
Performance figures Tractive effort 27,520 lbf (122.4 kN) Factor of adh. 4.63
Career Operators British Railways Power class 6P5F Numbers 72000–72009 Axle load class Route Availability 8 Locale Scottish Region, London Midland Region Withdrawn December 1962 – June 1966 Disposition All original locomotives scrapped, 72010 Hengist under construction.

The BR Standard Class 6, otherwise known as the Clan Class, was a class of 4-6-2 Pacific tender steam locomotive designed by Robert Riddles for use by British Railways. Ten locomotives were constructed between 1951 and 1952, with a further 15 planned for construction. However, due to acute steel shortages in Britain, the order was continually postponed until it was finally cancelled on the publication of the 1955 Modernisation Plan for the re-equipment of British Railways. All of the original locomotives were scrapped, but a new one is being built.

The Clan Class was based upon the BR Standard Class 7 Britannia Class design, incorporating a smaller boiler and various weight-saving measures to increase the route availability of a Pacific-type locomotive for its intended area of operations, the west of Scotland. The Clan Class received a mixed reception from crews, with those regularly operating the locomotives giving favourable reports as regards performance.^[2] However, trials in other areas of the British Railways network returned negative feedback, a common complaint being that difficulty in steaming the locomotive made it hard to adhere to timetables. Reports exist that suggest a degree of the disappointment with these locomotives was attributable to their being allocated to Class 7 work where they were only a Class 6 in reality; a problem put down to their very similar appearance to the BR Standard Class 7.

Some of the Clan Class locomotives took their names from the Highland Railway Clan Class which was being withdrawn from service at the time, indicating further their intended area of operations.^[3] The class was ultimately deemed a failure by British Railways, and the last was withdrawn in 1966. None survived into preservation, although a project to build the next locomotive in line, number 72010 Hengist, is progressing. Assembly of the frames has commenced at CTL Seal, Sheffield.