BR Standard Class 7

Infobox Locomotive
powertype=Steam
name = BR Standard Class 7 Clarke, David: "Riddles Class 6/7 Standard Pacifics", pp.80–87]


caption = 70013 "Oliver Cromwell" at York Railfest on 3 June 2004 prior to the start of its restoration to working order.
designer = Robert Riddles
builder = BR Crewe Works
builddate = 1951 - 1954
totalproduction = 55
whytetype = Whyte|4-6-2
gauge = RailGauge|sg|al=on|lk=on
leadingsize = convert|3|ft|4|in|m|2|abbr=on|lk=on
driversize = convert|6|ft|2|in|m|2|abbr=on|lk=on
trailingsize = convert|3|ft|6|in|m|2|abbr=on|lk=on
length = convert|67|ft|8|in|m|abbr=on|lk=on
weight = convert|143.0|LT|lk=on
tendertype = BR1, BR1A, or BR1D
fueltype = Coal
fuelc
convert|7.0|LT|lk=on BR1/BR1A tender
convert|9.0|LT|lk=on BR1D tender
waterc
convert|4250|impgal|L|abbr=on|lk=on BR1 tender
convert|5000|impgal|L|abbr=on|lk=on BR1A tender
convert|4750|impgal|L|abbr=on|lk=on BR1D tender
cylindercount = Two
cylindersize = convert|20|x|28|in|cm|abbr=on|lk=on
boilerpressure = convert|250|psi|abbr=on|lk=on
tractiveeffort = convert|32150|lbf|kN|abbr=on|lk=on
locale= Eastern Region of British Railways, London Midland Region of British Railways,
Scottish Region of British Railways, Southern Region of British Railways, Western Region of British Railways
powerclass= 7MT

The BR Standard Class 7, otherwise known as the "Britannia" Class, is a class of 4-6-2 "Pacific" steam locomotive designed by Robert Riddles for use by British Railways for mixed traffic duties. Fifty-five were constructed between 1951 and 1954. The design was a result of the 1948 locomotive exchanges undertaken in advance of further locomotive classes being constructed. Three batches were constructed at Crewe Works, before the publication of the 1955 .

The "Britannia" Class was based on several previous locomotive designs, incorporating the best practices in locomotive technology as regards labour-saving and lowering maintenance costs; various weight-saving measures also increased the route availability of a "Pacific"-type locomotive on the British Railways network. The "Britannias" received a positive reception from their crews, with those regularly operating the locomotives giving them favourable reports as regards performance. However, trials in some areas of the British Railway network returned negative feedback, primarily due to indifferent operation of the locomotive, with its effects on adhering to timetables.

The "Britannias" took their names from great Britons, former Star Class locomotives, and Scottish firths. The class remained in service until the last was withdrawn in 1968. Two survived into preservation, the doyen, number 70000 "Britannia", and 70013 "Oliver Cromwell". Number 70000 has hauled mainline excursions and 70013, after a period of display following limited steaming, returned to mainline steam in 2008 for the first time since leaving British Railways ownership.

Background

Locomotive exchanges were commissioned by the fledgling British Railways (BR) during 1948, to test the best and worst aspects of locomotive design within the Big Four railway companies that had existed before nationalisation.Langston, Keith: "Made in Crewe: 150 Years of Engineering Excellence", p. 60] The research gained from operating the best designs of the GWR, LMS, LNER and Southern railways on different areas of the British Railways network paved the way for several new classes of standardised locomotives to be constructed. These new locomotive designs were intended to replace some of the aging designs 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, whilst weight was kept within the margins laid down by the Light Pacifics, all of which were designed by Oliver Bulleid. Herring, Peter: "Classic British Steam Locomotives", pp. 176–177] 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.Clarke, David: "Riddles Class 6/7 Standard Pacifics", pp.12–13] A self-cleaning smokebox was used, 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".Clarke, David: "Riddles Class 6/7 Standard Pacifics", p. 13] The "Britannias" had convert|6|ft|2|in|m|abbr=on driving wheels, 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.Clarke, David: "Riddles Class 6/7 Standard Pacifics", p. 11]

The design also featured raised running plates above the wheels, which allowed easy access to the inside of the frames for purposes of lubrication.Clarke, David: "Riddles Class 6/7 Standard Pacifics", p. 12] 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. Wheel splashers were used on older locomotive designs to box in the top portion of the driving wheels for aesthetic reasons, and to prevent water and dirt from being thrown at the cab windows. The footplate was designed around the requirements of the operating crews, with a mock-up being constructed at Crewe to test ergonomics and usability.Nock, O.S.: "British Locomotives of the 20th Century; Volume 2, 1930-1960", p. 198] For ease of maintenance, availability of spare parts and increased reliability, two sets of Walschaerts valve gear were used, along with the largest cylinders capable of staying within the British loading gauge. This meant that all the valve gear was 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 British Railways' Derby Works, the new class was constructed at British Railways' Crewe Works between 1951 and 1954.Cox, E. S.: "British Railways Standard Locomotives", p. 61] The initial order was for 25 locomotives, but such was the demand for the "Britannias" on the Eastern Region that more were rushed through construction before the teething problems had been ironed out on the prototypes. In total, 55 members of the class were constructed over three batches at Crewe Works, where each was given improvements to improve reliability and efficiency, and to overcome flaws with the original design:
* 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.Clarke, David: "Riddles Class 6/7 Standard Pacifics", p. 22]

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.'Standard locomotives temporarily withdrawn' ("Railway Magazine"), p. 856] 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.Poultney, E.G.: 'Characteristics of the First Standard Locomotives for British Railways' ("Engineer"), p. 653] This was due to a problem of overheating bearings within the cranks, and difficulty in removing the LNER-type casings.Epton, R.: 'The power of the Riddles 'Britannia' 4-6-2s' ("Steam World"), p. 41] 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 gallons 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 executive 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 Scottish firths.Langston, Keith: "Made in Crewe: 150 Years of Engineering Excellence", p. 65 ] The locomotive naming ceremonies were carried out at various railway stations around the British Railways network. No. 70047 was never named.

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 its lower weight and high power transformed motive power over the restricted East Anglian lines.Stephenson, Brian: "BR Standard Steam Locomotives", p. 10–11] However, negative feedback was received from various operating departments, most notably on the Western Region, primarily out of preference for GWR-designed locomotive stock, and as such, Old Oak Common and Plymouth Laira depots declared that the class was surplus to requirements. However, Cardiff Canton depot displayed its 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, but 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.Clarke, David: "Riddles Class 6/7 Standard Pacifics", p. 62] 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.Stephenson, Brian: "BR Standard Steam Locomotives", p. 12]

Repairs to the class were undertaken at Crewe, Swindon and Doncaster Works until the financial constraints of the British Railways Modernisation Plan in terms of expenditure on steam began to preclude the regular overhaul of locomotives. During the mid-1960s, overhauls were carried out exclusively by Crewe Works. The first locomotive, number 70007 "Coer-de-Lion", was withdrawn from service in 1965, and the entire class was transferred to Carlisle Kingmoor and Glasgow Polmadie depots as steam was displaced by the dieselisation of British Railways. A succession of bulk withdrawals began in 1967, and the last, of number 70013 "Oliver Cromwell", took place at the very end of steam operation in Britain, in 1968. Subsequently, that locomotive was selected to represent the class in the National Collection. Only 70000 "Britannia", which was privately preserved, saw mainline service during the preservation era, until 2008, when 70013 "Oliver Cromwell"'s restoration was completed, and she worked part of the 15 Guinea Special. She now operates the Scarborough Spa Express.

Livery and numbering

The first member of the class was given a livery of plain black without lining; this was changed to the new standard British Railways Brunswick green that was applied to express passenger locomotives after nationalisation, despite being the locomotive being classed as mixed traffic. This was lined in orange and black, and the class was given the power classification 7MT.Clarke, David: "Riddles Class 6/7 Standard Pacifics", pp. 46–48] The "Britannias", were numbered under the new British Railways standard numbering system in the 70xxx series.Clarke, David: "Riddles Class 6/7 Standard Pacifics", p. 14] The locomotives were numbered between 70000 and 70054, and featured brass nameplates with an initial black background, followed by red, located on the smoke deflectors.Clarke, David: "Riddles Class 6/7 Standard Pacifics", p. 52] Towards the end of steam, plain green livery was substituted, with the touching-up of existing paintwork being preferred to full aesthetic overhaul.

Preservation

Two "Britannias" have survived, the original, number 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, 70013 was eventually selected to represent the class for the benefit of future generations. However, 70000 had been purchased 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.'How we saved "Britannia" ' ("The Railway Magazine"), p.22] Subsequently utilised on mainline railtours, the locomotive was out of use in the late 1990s, requiring work to bring it back to steam; 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), following an ownership dispute between Bressingham and the National Railway Museum. The locomotive returned to steam in May 2008 on the Great Central Railway. In July 2008 it appeared in WCRCs Open Weekend at Steamtown, Carnforth. August saw the locomotive return to the mainline, its first duty of service was the 1T57 'Fifteen Guinea Special' re-run from Manchester to Carlisle, 40 years after it performed the same duty in 1968..

:"For location details of the preserved locomotives, see: List of BR 'Britannia' Class locomotives"

Gallery

See also

* List of BR 'Britannia' Class locomotives

* BR standard class 7 70000 Britannia

* BR standard class 7 70013 Oliver Cromwell

Footnotes

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

* 'How we saved Britannia ' ("The Railway Magazine": 2007, 1,275), p.22

* 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

* Gilbert, Dr. P. T. (Ed.): "A Detailed History Of BR Standard Steam Locomotives Volume 1: Background to Standardisation and Pacific Classes" (Railway Correspondence & Travel Society (RCTS): 1994) ISBN 0901115819