111 The Great Bear
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''The Great Bear'', number 111, was a locomotive of the
Great Western Railway The Great Western Railway (GWR) was a British railway company that linked London with the southwest, west and West Midlands of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament on 31 August 1835 and ran ...
. It was the first
4-6-2 Under the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of four leading wheels on two axles, six powered and coupled driving wheels on three axles and two trailing wheels on one axle. The locomotiv ...
(Pacific) locomotive used on a railway in Great Britain, and the only one of its type built by the GWR.


Origins

There are differing views as to why Churchward and the GWR should have built a Pacific locomotive in 1908 when current and future locomotive practice for the railway was centred on the
4-6-0 A 4-6-0 steam locomotive, under the Whyte notation for the classification of steam locomotives by wheel arrangement, has four leading wheels on two axles in a leading bogie and six powered and coupled driving wheels on three axles with the abse ...
wheel arrangement. One suggestion is that ''The Great Bear'' was built in 1908 to satisfy demands from the directors for the largest locomotive in Britain, and much was made of the locomotive by the GWR's publicity department. However,
O. S. Nock Oswald Stevens Nock, Bachelor of Science, B. Sc., Diploma of Imperial College, DIC, Civil engineer, C. Eng, Institution of Civil Engineers, M.I.C.E., Institution of Mechanical Engineers, M.I.Mech.E., Institute of Locomotive Engineers, M.I.Loco. ...
was adamant that the design "was entirely due to Churchward, and not to outside influences that pressed the project upon him". Nock regarded the locomotive as "primarily an exercise in boiler design", with Churchward looking forward to a time when his Star Class locomotives could no longer cope with increasing loads. Others have referred to a statement made to the GWR board in 1906 about the GWR-designed 4-4-2 North Star where Churchward stated that a 4-6-2 would be bigger than required at that time but that such a design was being prepared. The order for ''The Great Bear'' was placed in January 1907.


Design

The front-end layout of the class was the same as that for the Star Class except that Churchward fitted diameter cylinders, the maximum possible without fouling the rear wheels of the front
bogie A bogie ( ) (in some senses called a truck in North American English) is a chassis or framework that carries a wheelset, attached to a vehicle—a modular subassembly of wheels and axles. Bogies take various forms in various modes of transp ...
. However, the design of the boiler was entirely new, and with a barrel of in length, which was exceptionally long both by contemporary and later standards. The main reason Churchward adopted the 4-6-2 wheel arrangement was to enable him to fit a wide
firebox Firebox may refer to: *Firebox (steam engine), the area where the fuel is burned in a steam engine *Firebox (architecture), the part of a fireplace where fuel is combusted *Firebox Records, a Finnish 8101705801record label * Firebox.com, an electro ...
over the trailing wheels. With a firebox surface of this was a 17.5% increase in size compared to the Star Class. It was also built with a Swindon No. 1 superheater.


Power classification

With the introduction of
Great Western Railway Power Classification From 1920, the cab side of Great Western Railway (GWR) steam locomotives bore a letter on a coloured disc, which enabled staff to quickly assess the capabilities of locomotives without the need to check tables of data. The letter showed the powe ...
in 1920, the power classification was "Special" (denoted by a black "+" on the red route availability disc,) although the tractive effort of fell within the range for "D".


Performance

In service, the performance of ''The Great Bear'' proved to be disappointing and not a significant improvement on existing classes. "The excessive tube and barrel length of 23 feet made for bulk rather than efficiency". Also, the axle boxes of the trailing wheels tended to become overheated due to their proximity to the firebox. Churchward attempted to improve the locomotive's performance by adding a Swindon No. 3 Superheater in 1913 and top-feed apparatus. However, the excellent performance of the Star Class and the advent of the
First World War World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
brought a stop to further experimentation without significant improvement.


Route availability

In addition to the disappointing performance, the locomotive had a highly restrictive route availability which limited its usefulness. The axle load restricted it to the Paddington to Bristol main line, although it was once recorded to have travelled as far west as Newton Abbot. The GWR route availability colour code for ''The Great Bear'' was Red.


Publicity value

Although not a technical success, ''The Great Bear'' was considered the company's flagship locomotive from its introduction until Churchward's retirement in 1922. With the introduction of 4073 ''Caerphilly Castle'' in 1923 with a higher
tractive effort As used in mechanical engineering, the term tractive force can either refer to the total traction a vehicle exerts on a surface, or the amount of the total traction that is parallel to the direction of motion. In railway engineering, the term tr ...
, ''The Great Bear'' ceased to have any publicity value and became an embarrassment. It was due for heavy repairs in January 1924 and so was withdrawn from service by Churchward's successor
Charles Collett Charles Benjamin Collett (10 September 1871 – 5 April 1952) was Chief Mechanical Engineer of the Great Western Railway from 1922 to 1941. He designed (amongst others) the GWR's Castle and King Class express passenger locomotives. Education ...
. It had run 527,272 miles by this time. Its regular engine driver was Thomas Blackall, originally from
Aston Tirrold Aston Tirrold is a village and civil parish at the foot of the Berkshire Downs about southeast of Didcot. It was part of Berkshire until the 1974 boundary changes transferred it to Oxfordshire. The 2011 Census recorded the parish's population ...
, Oxfordshire.


Rebuilding

"The front portion of the original frames and the number plates were used again but probably little else". No. 111 emerged as a 4-6-0 in the Castle Class, given the name '' Viscount Churchill''. Thereafter, the GWR did not use the Pacific wheel arrangement. No. 111 was withdrawn in July 1953 and scrapped later that year. One of the original nameplates is in the Science Museum.


Assessment

According to Cecil J. Allen, "''The Great Bear'' was one of the very few locomotive types that Swindon has produced, and in particular among the Churchward designs, to which the word 'failure' could be applied." Authorities differ as to Churchward's attitude to his locomotive. According to Le Fleming, "his dislike of 'The Bear' was well known", but Nock said that he had "a deep affection for the engine", although he came to regard it as "a
white elephant A white elephant is a possession that its owner cannot dispose of, and whose cost, particularly that of maintenance, is out of proportion to its usefulness. In modern usage, it is a metaphor used to describe an object, construction project, sch ...
" rather than a "Great Bear". He was disappointed to hear of ''The Great Bears destruction, and, upon hearing of
Nigel Gresley Sir Herbert Nigel Gresley (19 June 1876 – 5 April 1941) was a British railway engineer. He was one of Britain's most famous steam locomotive engineers, who rose to become Chief Mechanical Engineer (CME) of the London and North Eastern Rai ...
's plans to construct a Pacific for the Great Northern Railway, is said to have replied: "What did that young man want to build it for? We could have sold him ours!"


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External links

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