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BR Standard Class 7
File:BR 7MT 70013 'Oliver Cromwell' at York Railfest.JPG BR Standard Class 7 70013 Oliver Cromwell
Type and origin Power type Steam Designer Robert Riddles Builder Designed at BR Derby, constructed at BR Crewe Works Build date 1951–1952 Total produced 55
Specifications Configuration: ​  • Whyte 4-6-2 ("Pacific") Gauge Template:4ft8.5in Length 67 ft 8 in (22.5 m) Fuel type coal Fuel capacity 7 tons (7.11 tonnes) Water cap. 4,200 imp. gal (19,093.5 litres) (with BR1 tender) Boiler pressure 250 lbf/in² ( kPa) Cylinders 2 Cylinder size 19 in × 28 in (48 cm × 71 cm)
Performance figures Tractive effort lbf (kN)
Career Locale Great Britain

British Railways' standard class 7, otherwise known as the Britannia Class is a class of 4-6-2 steam locomotive designed for express passenger work, one of British Railways' standard classes of the 1950s. 55 examples were built and 2 survive.

Background

The locomotive exchanges that took place in 1948 resulted in the culmination of research concerning the best and worst aspects of locomotive design within the 'Big Four' companies that had existed before nationalisation. The best designs of the GWR, LMS, LNER and Southern railways were tested on different areas of the new British Railways (BR), paving the way for several new classes of locomotives to be constructed in order to replace aging equivalents inherited by British Railways.

The new classes were designed by Robert Riddles, who had previously designed the WD Austerity 2-8-0 and WD Austerity 2-10-0 locomotives for wartime use. The first design requested by the Railway Executive was for a new express passenger 'Pacific' locomotive, designed specifically to reduce maintenance using the latest available innovations in steam technology from home and abroad. Various labour-saving devices were utilised to produce a simple, standard, and effective design, able to produce equivalent power to some of the 'Pacifics' that were still available as legacies of the 'Big Four'.

Design features

The basic design of the 'Britannias' owed much to LMS building practices, especially when considering Riddles' previous career with the said railway. However, in keeping with the necessity to follow best practice in creating standardised steam locomotives, they utilised a variation of both boiler and trailing wheel of the Merchant Navy Class and Light Pacifics designed by Oliver Bulleid, with boiler pressure being rated at 250psi The firebox was also similar in having a rocking grate, which allowed the fire to be rebuilt without stopping the locomotive, removing both ash and clinker on the move. A self-cleaning smokebox was also utilised, which enabled ash to flow into the atmosphere, reducing the workload of the engine cleaner at the end of a working day. A single chimney was placed on top of the smokebox, which was unusual for a 'Pacific' type of locomotive. This was because the blastpipe was designed by S.O. Ell at Swindon Works, who advocated that "better results could be obtained from a well designed single chimney than some of the previous double chimney arrangements". The 'Britannias' had 6ft 2in driving wheels, which were a compromise that took into account the intended mixed-traffic role they were designed for. This meant that they were large enough for sustained fast-running with heavy passenger trains in tow, yet small enough to allow them to undertake more mundane tasks such as freight haulage.

The design also featured raised running plates above the wheels, which allowed easy access to the inside of the frames for purposes of lubrication. The lack of wheel splashers on this running plate also reduced the risk of the bearings overheating, by allowing more air to flow around the axles when at speed. The footplate was designed around the requirements of the operating crews, with a mock-up being constructed at Crewe for consultation purposes. For ease of maintenance in respect of the availability of spare parts and increased reliability, two sets of Walschaerts valve gear was used. This meant that all valve gear was situated on the outside, eliminating the problems encountered when operating three or four-cylindered locomotives, with poor access to the inside cylinders located between the frames. Boiler 'plumbing' was also generally exposed to maintain ease of access.

Construction history

Designed at the drawing offices of Derby Works, the new class was constructed at British Railways' Crewe Works between 1951 and 1954. The initial order was for 25 locomotives to be constructed, but such was the immediacy of demand regarding the 'Britannias' on the Eastern Region that more were rushed through construction before teething problems had been ironed out on the prototypes. In total, 55 members of the class were constructed over three batches at Crewe Works. These were:

• First batch: 70000–70024, constructed between January and October, 1951
• Second batch: 70025–70044, constructed between September 1952 and October 1953
• Third batch: 70045–70054, constructed in 1954.

Each batch was given improvements that were required in order to improve reliability and efficiency, and to overcome flaws with the original design.

Variations and modifications

Problems with the class were experienced immediately, with the first 25 locomotives being withdrawn in October 1951 after several complaints were received from crews regarding the driving wheels shifting on their axles. They were subsequently modified, and released back into revenue-earning service. Initially, the return cranks on the main driving wheels were of LNER block-type, as seen on Arthur Peppercorn's A1s and A2s, but this was changed to the simpler LMS four-stud fitting. This was due to a problem of overheating bearings within the cranks, and difficulty in removing the LNER-type casings. 70035–70039 were built with roller bearings on the leading and trailing coupled axles only and plain bearings on the remaining axles, whilst 70040–70049 were built with plain bearings throughout. Throughout service, the roller bearings used in remaining cases showed no advantage in reliability or cost.

Locomotive tenders were also changed as new, improved designs became available. Some examples of the second batch (70025–70029) were equipped with the BR1A tender, which had a higher water capacity of 5,000 gallons. Members of the third batch (70045–70054) were equipped with another tender design, that of the BR1D, which had 9 tons of coal, and 4,750 litres of water, due to the fact that they were intended for use on longer runs in the North of the railway network. This tender design also featured a steam-powered coal pusher, which eliminated the need for crew members to mount the tender to pull forward coal when the locomotive was at a stop.

Naming the locomotives

The name that was to be bestowed on the first class member caused great debate amongst the exectutive within British Railways, however, noted enthusiast and Bishop Eric Treacy suggested the name Britannia. This set the general theme of the naming process, which featured great Britons, although several deviations from the theme were undertaken. This lay with those that operated on the Western Region, which were given names of former Star Class locomotives, and those of the Scottish Region, which were granted the names of the various Firths within Scotland. The locomotive naming ceremonies were undertaken at various railway stations around the British Railways network.

Operational details

The class was well liked by crews in most regions of British Railways, with especially glowing reports from those operating them from Stratford depot on the Eastern Region, where their lower weight and high power transformed motive power over the restricted East Anglian lines. Negative feedback was however received from operating departments, notably on the Western Region, primarily out of preference for GWR-designed locomotive stock, and as such, Old Oak Common and Plymouth Laira depots proclaimed the class was surplus to requirements. However, Cardiff Canton depot displayed their liking for the class despite being part of the former GWR empire, and managed to obtain good results on South Wales passenger traffic.

The Midland Region also had favourable reports, although a marked consistency in losing time on the longer runs between Holyhead and Euston was recorded, although all complaints were down to the individual techniques of the operating crews. This was compounded by the irregular allocation of the class to depots all over the network, meaning that few crews ever had a great deal of experience in driving them. The Southern Region also had an allocation of seven in May 1953, when all Merchant Navy Class locomotives had been withdrawn for inspection following 35020 Bibby Line shearing a crank axle on the central driving wheel.

Repairs to the class were undertaken at Crewe, Swindon and Doncaster Works until the Modernisation Plan began to emerge. Overhauls became exclusive to Crewe Works, and the first locomotive, number 70007 Coer-de-Lion, was withdrawn in 1965. The entire class was transferred to both Carlisle Kingmoor and Glasgow Polmadie depots as steam was displaced by the dielelisation of British Railways. A succession of bulk withdrawals ensued in 1967, and the last, of number 70013 Oliver Cromwell, took place at the very end of steam operation in Britain during 1968. Subsequently, the latter locomotive was selected to represent the class in the National Collection.

File:70017 Arrow at Amergate with the Palatine, 9-1958.jpg

70017 Arrow rounds the curve at Ambergate railway station with The Palatine, September 1958.

Livery and numbering

The first member of the class initially sported a livery of plain black without lining, however, this was changed to a continuation of the new standard British Railways Brunswick green that was applied to express passenger locomotives after nationalisation. This was lined in orange and black, whilst the class was granted the power classification 7MT. The 'Britannias,' were numbered under the new British Railways standard numbering system in the 70xxx series. The locomotives were numbered between 70000 and 70054, featuring brass nameplates with a black background, located on the smoke deflectors.

Preservation

Two 'Britannias' have survived, the original 70000 Britannia and 70013 Oliver Cromwell. Number 70000 was originally selected to represent the class in the embryonic form of the future National Railway Museum, though was ultimately rejected due to the poor mechanical condition the locomotive was in. As a result, it was 70013 that was eventually selected to represent the class for the benefit of future generations. However, 70000 was bought privately from British Railways by the Britannia Locomotive Group, therefore also ensuring that the doyen of the class was to survive into the preservation era. Subsequently utilised on mainline railtours, the locomotive was out of use in the late 1990s, requiring work to bring it back to steam, and it was eventually sold to Pete Waterman and stored at Crewe. After a spell in storage on the Bressingham Steam Museum in Diss, Norfolk, 70013 was moved to the Great Central Railway (preserved) after an ownership dispute between Bressingham and the National Railway Museum. The locomotive has since been subject to overhaul, and is currently on course for a return to steam and mainline use in 2008, the anniversary of the end of steam in Britain, where it will take centre stage.

Gallery

• 70037 Hereward the Wake (right) with Royal Scot 46115 Scots Guardsman at Carlisle Kingmoor depot, 1964.
  70037 Hereward the Wake (right) with Royal Scot 46115 Scots Guardsman at Carlisle Kingmoor depot, 1964.
• 
  70015 Apollo at Carlisle, probably 1960.

See also

• List of BR 'Britannia' Class locomotives

References

• Clarke, David: Riddles Class 6/7 Standard Pacifics (Locomotives in Detail volume 5) (Ian Allan: Hinckley, 2006) ISBN 0711031770

• Cox, E. S.: British Railways Standard Locomotives (Ian Allan: London, 1966)

• Epton, R.: 'The power of the Riddles 'Britannia' 4-6-2s' (Steam World: 2006, 223)

• Herring, Peter: Classic British Steam Locomotives (Abbeydale Press: London, 2000) Section "BR 'Britannia' Class 7" ISBN 1861470576

• Langston, Keith: Made in Crewe: 150 Years of Engineering Excellence (Mortons Media: Horncastle, 2006) ISBN 0955286808

• Nock, O.S.: British Locomotives of the 20th Century; Volume 2, 1930-1960 (Cambridge: Patrick Stephens, 1984)

• Poultney, E.G.: 'Characteristics of the First Standard Locomotives for British Railways' (Engineer: 1951, 191)

• 'Standard locomotives temporarily withdrawn' (Railway Magazine: 1951, 97)

• Stephenson, Brian: BR Standard Steam Locomotives (Hinckley: Ian Allan, 2007) ISBN 9780711012455

Further reading

• A Detailed History Of BR Standard Steam Locomotives. Volume 1. Background to Standardisation and Pacific Classes Railway Correspondence & Travel Society (RCTS). Author? (1994) ISBN 0-901115-81-9