Great Western 4-6-2 Locomotives in Great_Britain

Class Great Bear (Locobase 3027)

See Ahrons (1927); "4-6-2 Express Passenger Enginer: Great Western Railway", Railway Engineer, Volume 28, No 3 (March 1908), pp. 78; "The Pacific Type of Locomotive--English & American", Railway Magazine, Volume 22, pp.207-208, Pacific Type in Great Britain", Railway and Locomotive Engineering", Volume , No 4 (April 1908), pp. 151; and "Pacific Type Locomotive, Gt Western Ry," The Locomotive Magazine, Volume XIV [14] (15 February 1908), p. 26-27. See also "Number 111, 'The Great Bear'", Great Western Archive at [], last accessed 15 January 2023. (Thanks to Alexander Blessing for his 15 January 2023 email providing key details and a cite to the Railway Engineer report. Thanks also to Peter Christener for his 27 October 2024 email supplying a fully dimensioned elevation diagram. )

The only British Pacific engine until 1922 and the only one that would ever run on the GWR, this forebearer of later Gresley designs was designed by George Jackson Churchward. John Daniel of the Great Western Archive summarizes the historical background for this malproportioned locomotive: "Even today, nobody absolutely knows the real reasons for building The Great Bear. It has been said that it was built purely for prestige purposes as this was the first Pacific 4-6-2 created in Britain, while others say that G. J. Churchward himself wanted to prove that his designs were sound for large locomotive boilers."

Long-boilered, tapering from 66" in the front to 72" at the slab-sided Belpaire firebox, which had a total heating surface of 158 sq ft (14.68 sq m), to which could be added 24.22 sq ft (2.25 sq m) of arch tube surface area. This latter number seems relatively low for so large a design. The outside cylinders drove the middle axle, the inside cylinders the front set of drivers. Each side was actuated by one set of valve gear operating the piston valves. At the time, this was the largest boiler pressed to such a high degree on an English locomotive.

Glover (1967) comments that had Churchward's design not been so rigidly derived from his Star-class Ten-wheelers, this engine might have revolutionized express-engine design in England. Instead, the location of the cylinders meant they could not increase in size to exploit the large boiler. Moreover, the long boiler barrel came from the traditional placement of the smokebox over the bogie pivot and the firebox over the trailing axle. 23-foot long boiler tubes must have relatively inefficient.

Such was the Great Bear's size, Daniel noted, "it was restricted to the Paddington to Bristol line due to its high axle loading g giving it a route availability of 'Special Red' as indicated by a black 'plus' sign on a red disc .

In any case, it only ran until 1924, when it was dismantled, with some parts being reused by C B Collett to turn out a 4-6-0 in 1924.