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Bulleid MN "Merchant Navy" Class 4-6-2

photograph: Roy Vandersteen collection

Nº21C1 Channel Packet caused quite a sensation when first unveiled to the public on 18th February 1941 with her unusual shape and, for Britain, number. In the early years of these locomotives they were frequently known by the nick-name "Channel Packets" rather than "Merchant Navies", after the first in the class. She is in matt malachite and has cast number plates, though that on the sloping front will soon be removed and replaced with a painted number on the vertical face immediately below.

When in March 1938 the Board of the Southern Railway authorised construction of ten locomotives of a new mainline passenger design neither they, nor anyone who knew of CME Oliver Bulleid's work whilst assistant to Nigel Gresley on the GNR and LNER, could scarcely imagine the machine that eventually emerged from the works. After an eight coupled configuration had been turned down by the Civil Engineer a more conventional Pacific wheelbase was settled upon, but thereafter very little else was conventional about this engine. Bulleid was an imaginative and perhaps intuitive (rather than precise) designer leading to many changes of mind throughout the design and construction process. The boxy bodywork, described as "air-smoothed" rather than streamlined (being designed to go through carriage washing plants) and Bulleid-Firth-Brown (BFB) wheels were merely the cloaking for a host of innovative features - some untried and untested - and methods of construction introduced with the laudable aim of easing the workload for (and no doubt reduce the costs of) loco crew and maintenance staff. In fact some innovations introduced cause and effect to ripple through the design with one innovation introducing extra weight somewhere in the loco requiring another innovation elsewhere to reduce weight.

Novel features included an all-time high boiler pressure of 280lb p.s.i., clasp brakes, welded steel firebox with thermic syphons, steam operated fire doors (novel in Britain), a steam driven electrical generator providing comprehensive headcode, inspection and cab lighting, a cab layout permitting the driver and fireman to work without getting in each other's way, but chief of all a totally enclosed motion encased in an oil bath situated between the frames. This motion itself included the new feature of a chain driven three throw crank shaft operating valve gears for each cylinder. In his motion gear Bulleid was strongly influenced by automobile design with its potential increased reliability and reduced maintenance compared to conventional locomotive motion design.

The "Southern" plate on the smokebox door was unpopular with loco crews as it resembled an upside-down horseshoe so was soon replaced with a "Southern Roundel" with the added section carrying the date of the manufacture. Despite a wooden mock-up being made immediately after nationalization, the roundel was not replaced with a similar one bearing the legend "British Railways". In the early days of BR the numbers, by now simply painted, carried the prefix 'S' in front of the Southern number, but when the locos were renumbered in the 350xx series, this was replaced by a cast LMS-style plate on the smokebox door, hidden in the photograph below by the train headboard.

It was originally intended to name this class after Allied victories. Nº21C1 had been lined up for the name The Plate but in 1941 there had been few victories to commemorate. Consideration was then given to naming them after Commonwealth capitals but the Chairman of the Union Castle Line then suggested naming them after shipping companies which had called at Southampton Docks in peacetime.

The first member of the class - Nº21C1 Channel Packet - was completed at Eastleigh Works in February 1941 - design and construction having been overtaken by the outbreak of World War Two. Two further batches of ten were ordered, the final batch in the early days of nationalisation which never carried Bulleid notation numbers. With a tractive effort of 37500lb at 85% boiler pressure the Merchant Navy class provided the Southern with a modern powerful express passenger locomotive. Three members of the class, Nº35017 Belgian Marine, Nº35019 French Line C. G. T. and Nº35020 Bibby Line (the reserve engine), all temporarily matched with higher capacity LMS water scoop tenders, took part in the British Railways locomotive exchange trials of 1948 in the express passenger class trials where they more than held their own.

However in the early days the class experienced persistent teething troubles whilst in their original condition some of the novel features failed to deliver their original labour and cost saving intentions. The steam reverser and the oil bath enclosed motion gave particular problems. It proved impossible to keep the oil bath sealed with the result that the boiler lagging became oil soaked and prone to catching fire, and the class was also known for its slippery starts. The air-smoothed casing also caused a maintenance headache, and they were inefficient users of coal and oil.

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  • Poster
     
    This is a photograph of a Southern Railway poster featuring the Merchant Navy class, portraying by its technology the railway company as being a modern progressive organisation.
    Photograph by Michael Taylor.
  • 21C3
    Salisbury
    Nº21C3 Royal Mail engaged in changing engines at Salisbury on a Plymouth-bound train. The number can now be seen to be painted on the vertical face. The letter 'C' is also noticeably larger than the numerals.
    Photograph: Mike Morant collection.
  • 21C4
    Waterloo
    Nº21C4 Cunard White Star at Waterloo with a special train for the maiden ordinary passenger carrying voyage of the "Queen Elizabeth", 16th October 1946. Note the "quartering" of the buffers and the letter 'C' which is now slightly smaller than the numerals!
    Whilst an Exmouth Junction engine, a low flying German aircraft shot at Nº21C4 on 30th November 1942 at Crannaford, near Whimple.
    Photograph courtesy Jerry Ricketts and stated to be in the Public Domain when posted on the alt.binaries.pictures.rail newsgroup.
    It will be removed if the original author deems that to be necessary.
  • 35006
    Exmouth Jn
    Nº35006 Peninsular & Oriental S N Co on shed at Exmouth Junction sometime between December 1948 when she was renumbered and March 1951 when she was painted in BR blue. This loco, now restored at the Gloucestershire Warwickshire Railway, had a unique claim - she was the only one of her class to remain at one shed (Salisbury) for the whole of her SR/BR career. She also had the same tender attached throughout, though this was sold separately from the engine after being sent to Woodhams at Barry Island.
    Photograph: Mike Morant collection.
  • 35008
    Salisbury
    Nº35008 Orient Line, calling at Salisbury. This loco was involved in an accident in 1947 when she collided with an electric service whilst running in with a West of England train, doing considerable damage to her front end. The loco was soon repaired, however, was fitted with a modified cab and returned to traffic with a fresh coat of malachite green, the last of the class to be re-painted from the Southern Livery. She was modified in May 1957.
    Photograph Mike Morant collection.
  • 35027
    Victoria
    Nº35027 Port Line at Victoria. She is in the experimental blue livery applied to all bar three of the Merchant Navy class locos. Note the difference in appearance when compared with Nº21C1 and Nº21C3. Many modifications to the "air-smoothed" casing were tried before this general arrangement was settled on, mainly in an effort to avoid smoke drifting down and obscuring the driver's view! She now has the "Vee" shaped cab that, with its angled front spectacle plates, increased vision and reduced glare.
    Port Line is carrying the prestigious "Golden Arrow" regalia of headboard, arrows and British and French flags.
    Photograph: Roy Vandersteen collection.
  • 35015
    Waterloo
    A blue-liveried Nº35015 Rotterdam Lloyd Line backing out of Waterloo in 1951, with an unknown M7 ahead of it, having worked the Up Bournemouth Belle.
    Photograph by Robert Whitfield.
  • 35027
    Victoria
    A blue Nº35027 Port Line at Victoria during 1951, complete with Golden Arrow regalia.
    Photograph by Robert Whitfield.
  • 35014
    Eastleigh
    Nº35014 Nederland Line passing Eastleigh with the up Bournemouth Belle on 28th March 1954.
    Photograph: Mike Morant collection.
  • 35008
    Clapham Jn
    Nº35008 Orient Line again and M7 class Nº30321 in the carriage sidings at Clapham Junction circa 1955/6. This photo is a little later than the one above as the valances covering the cylinders and leading up to the buffer beam have now been removed.
    Photograph by Mike Morant.
  • 35003
    Worting Jn
    Nº35003 Royal Mail Line photographed near Worting Junction on 19th July 1958.
    Photograph: Mike Morant collection.
  • 35006
    Eastleigh
    Another view of Nº35006 Peninsular & Oriental S N Co, this time at Eastleigh and looking both quite different from the photo on the previous page and a little the worse for wear. Date not known.
    Photograph by Mike Morant.

This page was last updated 15 March 2021

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