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EspañolSR MERCHANT NAVY CLASS
The 'SR Merchant Navy Class,' given the nickname "Spam Cans" or "Packets" by locomotive drivers after the doyen of the class, was originally a class of air-smoothed 4-6-2 steam locomotive designed for the Southern Railway by Oliver Bulleid. The Pacific design was chosen out of several others proposed by Bulleid. The first members of the class were constructed during the Second World War, with the final total eventually amounting to 30 locomotives.
The 'Merchants' incorporated many innovations that revolutionised British steam locomotive design, such as thermic syphons. The class was named after Merchant Navy shipping lines involved in the Battle of the Atlantic, and latterly those which used Southampton docks. This was an astute publicity masterstroke for the Southern Railway.
Due to problems with some of the more novel features of Bulleid's design, all members of the class were subsequently rebuilt by British Railways during the late 1950s. The 'Merchants' operated until the end of Southern steam in July 1967, and a third of the class have been saved from scrapping, and can be seen on heritage railways and the mainline throughout Britain.
Background
The gestation of the Merchant Navy Class Pacifics went as far back as 1938, when Sir Eustace Missenden, the Director of the Southern Railway, realised that the company lagged behind in terms of pioneering locomotive design.
Bulleid, who had been brought in from the LNER to replace Richard Maunsell as Chief Mechanical Engineer (CME) believed that it was time for the Southern to lead the field with the construction of an eight-coupled machine. The first suggestion of this type was for a 4-8-2, although this was quickly modified to a 2-8-2 with a Krauss-Helmholtz "bogie Bissel". However, both these propositions were resisted by the civil engineer, so a new 4-6-2 Pacific design was settled upon.
This was due to the fact that the newest locomotive class on the railway was an 0-6-0 Q Class that was built to Victorian principles. Morgan, John Scott: ''The Story of the Q1s''
Intended primarily for express passenger and semi-fast work in Southern England, the new class was also designed to be equally adept at freight workings due to the nominal 'mixed traffic' classification Bulleid applied to the class for them to be built in wartime.
Design features
The locomotives were constructed with Bulleid's revolutionary use of welding for inner firebox construction as opposed to rivets. Maximum boiler pressure was also higher than any other regular service locomotive, at 280psi. They also sported Bulleid's novel, if highly troublesome, chain-driven valve gear , and were provided with 'air-smoothed' casings and Bulleid-Firth-Brown wheels.[1][2] The 'air-smoothed' casing was not regarded as streamlining, a fact demonstrated by the extremely flat front end, but as an aid to cleaning the locomotive via the use of a carriage washer, representing another attempt to reduce labour during the post-war period. Creer,S & Morrison,B: ''The Power of the Bulleid Pacifics'', p. 21 Electric lighting was also provided, powered by a steam generator below the footplate, as well as a steam operated treadle that used steam pressure to open the firehole doors as an aid to the fireman.''Bulleids in Retrospect,'' Transport Video Publishing, Wheathampstead, Hertfordshire.
The Southern-built locomotives had several detail differences, with the removal of certain design features, such as the steam operated firehole door treadle. The entire class was subjected to further modifications during the brief time they operated under the Southern Railway. The main change being the redesign of the footplate spectacle plates, the small windows in the front face of the cab, which were redesigned to the angled profile that all Bulleid-designed locomotives depict post-Nationalisation. Originally, the spectacle plates were at right-angles to the air-smoothed casing, offering limited vision ahead for the driver.Creer,S & Morrison,B: ''The Power of the Bulleid Pacifics'' pp. 40-41
Construction history
The Southern Railway initially constructed ten 'Merchants' at Eastleigh Works: the first, prototype Merchant Navy Class locomotive 21C1 ''Channel Packet'', was completed in March 1941; the last was Battle of Britain Class number 21C19 ''French Line C.G.T.'', in September 1945.[1] A second batch soon followed the first, beginning with 21C11 ''General Steam Navigation'', in 1944. The Southern-built batches had variations in material used for the 'air-smoothed' casing with a chane from sheet steel to an asbestos compound, forced upon the manufacturer by wartime expediency. This resulted in several class members having a horizontal strengthening rib running down the length of the casing.
The class was defined as mixed-traffic locomotives by Bulleid in order to surmount administrative measures put in place by the wartime government preventing the construction of express passenger locomotives.Creer,S & Morrison,B: ''The Power of the Bulleid Pacifics'', p. 7 A final batch was constructed under the auspices of British Railways. The Southern-built batch years were as follows:
★ 21C1-21C10: Completed 1941-1942
★ 21C11-21C20: Completed 1944-1945
The Merchant Navy design spawned the construction from 1945 of the West Country/Battle of Britain classes, resulting in lighter locomotives with increased route availability. This was necessary on the Southern's 'Withered Arm' West of Exeter, as Merchant Navy Class locomotives were banned from this section due to weight restrictions.
Naming the locomotives
The Southern Railway considered naming the locomotives after victories of the Second World War to the extent that a mocked-up nameplate "River Plate" was produced.Burridge, Frank: ''Nameplates of the Big Four'', p. In the event, the chairman of the Union Castle Line suggested naming them after shipping companies which had called at Southampton Docks in peacetime.[2] This idea had more suitability in 1941 due to the fact that the shipping lines were heavily involved in the Atlantic convoys to and from Britain during the Second World War.Burridge, Frank: ''Nameplates of the Big Four'', p.
The British Railways engines
A final batch of ten locomotives was built after nationalisation, never to carry a Southern Railway number. Herring, Peter: ''Classic British Steam Locomotives'', pp.
The British Railways standard numbering system placed them in the series 35021–35030, and the batch was completed at Eastleigh between 1948–1949. The British Railways batch had detail differences to the Southern Railway-built versions concerning fuel and water capacity.
Rebuilding
Between 1956 and 1960, British Railways rebuilt the entire class to a more conventional design by R. G. Jarvis, adopting many features from the BR Standard locomotives that had been introduced since 1950.[3] The 'air-smoothed' streamlined casing was removed and replaced with conventional boiler cladding, and the chain-driven valve gear was replaced with modified Walschaerts valve gear, whilst the boiler pressure was reduced from 280 to 250psi. The first to be outshopped from Eastleigh was 35018 ''British India Line'' in 1956. The final example, 35028 ''Clan Line'', was completed in 1960.
The rebuilt Merchant Navy Class was also to influence the design of the future rebuilding of 60 Light Pacifics. As a result of the rebuilding and the implementation of Walschaerts valve gear, the rebuilts were prone to hammerblow on the track, a complaint that was not evident with as-built locomotives due to the balancing required to operate the gear.
The rebuilt locomotives were scrapped relatively soon after their rebuilding, an indication of the waste in resources made by British Railways, as some engines such as 35014 ''Rotterdam Lloyd'' were withdrawn as early as 1964. The last few engines in traffic survived until the end of steam on the Southern Region in the summer of 1967.
Operational details
The locomotives were largely successful, though their heavier axle loading meant that they were banned from certain areas of the Southern Railway, and later, the British Railways (Southern Region) network. The locomotives were often prone to wheelslip, and required very careful driving when starting a heavy train from rest, but once into their stride they were noted for their free running, excellent steam production and being remarkably stable when hauling heavy expresses.
A perennial problem with the unrebuilt Merchant Navy Class locomotives lay with the leaks from the oil bath onto the wheels that in turn splashed oil onto the boiler lagging in service. Once saturated with oil, the lagging attracted coal dust and ash which provided a combustible material, and as a result of the heavy braking of the locomotives, sparks would set the lagging on fire underneath the air-smoothed casing.[4] The local fire brigade would invariably be called to put the fire out, with cold water coming into contact with the hot boiler, causing stress to the castings. Many photographs show an unrebuilt with 'cockled' (warped) casings, a result of a lagging fire.
Another problem was experienced with the exhaust, which beat down onto the air-smoothed casing when the engine was on the move, obscuring the driver's vision from the cab.Creer,S & Morrison,B: ''The Power of the Bulleid Pacifics'' The rebuilts were provided with LMS-style smoke deflectors and the lack of air-smoothed casing also helped reduce the problem. Creer,S & Morrison,B: ''The Power of the Bulleid Pacifics'', pp. 74-75
Livery and numbering
Southern Railway
Livery was Southern Railway Malachite Green with "Sunshine Yellow" horizontal lining and lettering. All class members that operated during the Second World War were eventually outshopped in Southern Railway Wartime Black livery, with green shaded 'Sunshine' lettering. However, this was reverted back to Malachite Green upon the ending of hostilities.
21C1 ''Channel Packet'' originally had an inverted horseshoe on the smokebox door, indicating its Southern origin, however, locomotive crews believed this to be 'unlucky.' A resultant re-design meant that this became a roundel, the gap being filled by the date and place of construction, therefore acting as a builder's plate. The background was painted red. Early members of the class had cast iron numberplates and gilt 'Southern' plates on the tender, however these were subsequently replaced by transfers.
Bulleid advocated a continental style of locomotive nomenclature, based upon his experiences at the French branch of Westinghouse Electric before the First World War, and those of his tenure in the rail operating department during that conflict. The Southern Railway number followed an adaptation of the UIC classification system where "2" and "1" refer to the number of unpowered leading and trailing axles respectively, and "C" refers to the number of driving axles – in this case three. All the locomotives therefore carried the prefix 21C.Burridge, Frank: ''Nameplates of the Big Four'', p.
Post-1948 (nationalisation)
Initial livery after nationalisation in 1948 was modified Southern malachite green and sunshine yellow with "British Railways" on the tender, and the Bulleid numbering system was temporarily retained with an "S" prefix such as S21C1. The second livery carried was the British Railways Experimental Express Passenger Blue with red or white lining, and was carried until 1952. From then on, the locomotives carried British Railways Brunswick Green livery with orange and black lining, and this livery was perpetuated after rebuilding. The locomotives were renumbered under the British Railways standard system in the series 35001–35030 from 1949.[5] Rebuilt locomotives were also outshopped in BR Brunswick Green, with the BR crest on the tender sides.
Preservation
Many of the class have survived into preservation thanks to the famous Barry Scrapyard in South Wales, where steam engines bought from British Railways for scrapping were stored, rather than cut up. One engine, 35028 ''Clan Line'', was bought by the Merchant Navy Locomotive Preservation Society direct from British Railways in 1967. A third of the Pacifics have survived into the preservation era, although it is very likely that many will never steam again. Also, no unrebuilt Merchant Navy Class locomotives are in existence.
Preserved Merchant Navy Class locomotives
Number 35010 "Blue Star" on Static display awaiting restoration at the Colne Valley Railway
★ 35005 Canadian Pacific, Watercress Line (Mid-Hants Railway)
★ 35006 Peninsula and Oriental S N Co., Gloucestershire Warwickshire Railway
★ 35009 Shaw Savill, Watercress Line (Mid-Hants Railway)
★ 35010 Blue Star, Colne Valley Railway
★ 35011 General Steam Navigation, RAF Binbrook
★ 35018 British India Line, Watercress Line (Mid-Hants Railway)
★ 35022 Holland-America Line, Southall, London
★ 35025 Brocklebank Line, Great Central Railway (preserved)
★ 35027 Port Line, (Sold 2003 for private ownership) Stored pending overhaul at Southall, London
★ 35028 Clan Line, Stewarts Lane, London
★ 35029 Ellerman Lines, National Railway Museum ''(sectioned to show internal construction)''
Footnotes
1. Southern E-Group (2004) Bulleid MN "Merchant Navy" Class 4-6-2, Retrieved April. 16, 2007. For a picture of ''Channel Packet'' as built.
2. Southern E-Group (2004) Bulleid MN "Merchant Navy" Class 4-6-2, Retrieved April. 16, 2007. For details of the naming process.
3. Southern E-Group (2004) Rebuilt Bulleid MN "Merchant Navy" Class 4-6-2, Retrieved April 16, 2007. For more pictures of the rebuilt locomotives.
4. Southern E-Group (2004) Bulleid MN "Merchant Navy" Class 4-6-2: Notes from a Bulleid Fundamentalist, Retrieved April 16, 2007. For details on the lagging fires, they were common to both Merchant Navys and Light Pacifics.
5. Ian Allan ABC of British Railways Locomotives, winter 1958–59 edition
References
★ Burridge, Frank: ''Nameplates of the Big Four'' (Oxford Publishing Company: Oxford, 1975) ISBN 0902888439
★ Creer,S & Morrison,B: ''The Power of the Bulleid Pacifics'' (Oxford Publishing Company: Oxford, 2001) ISBN 0860930823
★ Harvey, R. J.: ''Bulleid 4-6-2 Merchant Navy Class (Locomotives in Detail series volume 1)'' (Hinckley: Ian Allan Publishing, 2004), ISBN 0711030138
★ Herring, Peter: ''Classic British Steam Locomotives'' (Abbeydale Press: London, 2000) Section "Merchant Navy Class" ISBN 1861470576
★ Ian Allan ABC of British Railways Locomotives, winter 1958–59 edition
★ Morgan, John Scott: ''The Story of the Q1s'' (KRB Publications: Bishop's Waltham, 2003) ISBN 0954485912
Further reading
★ Bulleid, H. A. V.: ''Bulleid of the Southern'' (Hinckley: Ian Allan Publishing, 1977) ISBN 071100689X
★ Morrison, B: '' The Power of the Merchant Navies'' (Oxford Publishing Company: Oxford, 2007) ISBN 0860936074
★ Ian Allan ABC of British Railways Locomotives, winter 1962–63 edition
★ Day-Lewis, S: ''Bulleid, Last Giant of Steam'' (London: George Allen & Unwin, 1964) P. 186
★ Reed, B: “Merchant Navy Pacifics” Loco Profile series 22, page 231 (Profile publications, Berkshire, England, 1972)
See also
★ List of SR Merchant Navy Class locomotives
External links
★ Southern e-group page
★ General Steam Navigation 35011
★ Peninsular & Oriental S.N. Co 35006 Home page
★ Clan Line 35028 Home page
★ Bullied Society Merchant Navy information
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