BR Standard Class 6P5F 4-6-2

BR Standard Class 6P5F 4-6-2

BR Standard Class 6P5F 4-6-2 No. 72005 Clan Macgregor at Chester in 1964 (photo: Ben Brooksbank)

The British Railways standard Clan Class 6P5F 4-6-2 Pacific tender steam locomotives were designed at Derby works under the oversight of R. A. Riddles and built at Crewe Works between 1951 and 1952. Only 10 were built (numbered 72000 to 72009) for use in the West of Scotland. another batch of 15 was planned but repeatedly postponed and eventually cancelled. The class were all named after Scottish Clans, some were previously applied to the Highland Railway Clan Class 4-6-0s that were withdrawn between 1943 and 1950.

The design was a lightweight version of the BR Standard Britannia Class 7 Pacific with smaller cylinders and lower boiler pressure. Using the Pacific wheel arrangement rather than 4-6-0 allowed the use of a wide firebox capable of burning a range of coal types. The locomotives had two outside cylinders, Walschaerts valve gear and used BR1 tenders.

The Clans had indifferent performance and did not impress when tested away from their normal operating routes. However, being pacifics, they tended to be used on heavier trains than considered normal for a Class 6. The Class was withdrawn between 1962 and 1966. None have been preserved, although a new locomotive, number 72010 Hengist, is under construction by The Standard Steam Locomotive Company Ltd. this is the 1000th locomotive to be built to a British Railways standard design.

BR Standard Class 6P5F 4-6-2 specification

Length: 68 ft 9 in (20.96 m)
Width: 8 ft 8 3?4 in (2.66 m)
Height: 13 ft 0½ in (3.98m)
Gauge: 4 ft 8½ in (1.435m)
Driving wheel dia: 6 ft 2 in (1 880mm)
Boiler Pressure: 225 psi (1.55 MPa)
Cylinders: 19½ x 28 in (495 x 711mm)
Loco weight: 86 tons 19 cwt (88.345 tonnes)
Tractive effort: 27,520 lbf (122.4 kN)

Last updated 02/11/11