LNER Class A4

LNER Class A4
60009 Union of South Africa in 1951
Power type	Steam
Designer	H. N. Gresley
Builder	LNER Doncaster Works
Build date	1935–1938
Total produced	35
Configuration	4-6-2
UIC classification	2'C1h
Gauge	4 ft 8 1⁄2 in (1,435 mm)
Leading wheel diameter	3 ft 2 in (0.965 m)
Driver diameter	6 ft 8 in (2.032 m)
Trailing wheel diameter	3 ft 8 in (1.118 m)
Locomotive weight	102 tons 19 cwt (230,600 lb or 104.6 t)
Locomotive & tender combined weight	167 tons 2 cwt (374,300 lb or 169.8 t)
Fuel type	Coal
Fuel capacity	8 tons 0 cwt (17,900 lb or 8.1 t)
Water capacity	5,000 imperial gallons (23,000 l; 6,000 US gal)
Boiler pressure	250 psi (1.72 MPa)
Cylinders	Three
Cylinder size	18.5 × 26 in (470 × 660 mm)
Top speed	90 miles per hour (140 km/h) in Regular Service (126.4 miles per hour (203.4 km/h) maximum recorded)
Tractive effort	35,455 lbf (157.71 kN)
Locomotive brake	Vacuum
Train brakes	Vacuum 60009, 60007 & 60019 have been fitted with air brakes
Career	LNER, BR
Class	A4
Power class	BR: 8P6F
Number in class	35
Number	LNER: 2509–2512, 4462–4469, 4482–4500, 4900–4903, LNER 1–34 (not in order), BR: 60001–60034
Nicknames	"Streak"
Withdrawn	1942, 1962–1966
Disposition	6 preserved

The Class A4 is a class of streamlined 4-6-2 steam locomotive designed by Nigel Gresley for the London and North Eastern Railway in 1935. Their streamlined design gave them high-speed capability as well as making them instantly recognizable, and one of the class, 4468 Mallard, has the official record as the fastest steam locomotive in the world. Thirty-five of the class were built to haul express passenger trains on the East Coast Main Line route from London Kings Cross via York and Newcastle to Edinburgh, Scotland. They remained in service on the East Coast mainline until the early 1960s when they were replaced by Deltic diesel locomotives. Several A4s saw out their remaining days until 1966 in Scotland, particularly on the Aberdeen - Glasgow 3-hour express trains, for which they were used improve the timing from 3.5 hours.

Overview

Gresley introduced the Class A4 locomotives in 1935 to haul a new streamlined train called the Silver Jubilee to run between London King's Cross and Newcastle. The new service was named in celebration of the 25th year of King George V's reign.

During a visit to Germany in 1933, Gresley had been inspired by the high-speed streamlined "Flying Hamburger" diesel trains, and indeed the LNER had considered purchasing similar trains for use from London to Newcastle. However, the diesel units of the time did not have the desired passenger carrying capacity and the capital investment in the new technology was prohibitive.

Gresley was sure that steam could do the job equally well and with a decent fare-paying load behind the locomotive and so, following trials in 1935 with one of Gresley's A3 Pacifics No.2750 Papyrus, which recorded a new maximum of 108 mph (173.8 km/h) and completed the journey in under four hours, the LNER authorised Gresley to produce a streamlined development of the A3.^{[citation needed]} Initially four locomotives were built, all with the word 'silver' as part of their names, the first being 2509 Silver Link; the others being 2510 Quicksilver, 2511 Silver King and 2512 Silver Fox. During a press run to publicise the service, Silver Link twice achieved a speed of 112.5 mph (181.1 km/h), breaking the British speed record and sustained an average of 100 mph (160.9 km/h), over a distance of 43 mi (69.2 km).

Following the commercial success of the Silver Jubilee train, other streamlined services were introduced: the Coronation (London-Edinburgh, July 1937) and the West Riding Limited (Bradford & Leeds-London & return, November 1937) for which more A4s were specially built.

Design

The A4 Pacifics were designed for high-speed passenger services. The application of internal streamlining to the steam circuit, higher boiler pressure and the extension of the firebox to form a combustion chamber all contributed to a more efficient locomotive than the A3, consumption of both coal and water being reduced. A further improvement to the design was the fitting of a Kylchap double-chimney first introduced on 4468 Mallard, built in March 1938. This device improved the free-steaming capabilities of the locomotives further, and the final three locomotives of the class (4901 Capercaillie, 4902 Seagull and 4903 Peregrine) were fitted with the Kylchap exhaust from new; and eventually the rest of the class acquired it in the late 1950s.

This class was also noted for its streamlined design, which not only improved its aerodynamics, thus increasing its speed capabilities, but also created an updraught to lift smoke away from the driver's vision, a problem inherent in many steam locomotives particularly those operated with short cut off valve events, smoke deflectors being an alternative answer to the same problem. The distinctive design made it a particularly attractive subject for artists, photographers and film-makers. The A4 Class locomotives were known affectionately by train spotters as "streaks".

The streamlining side skirts (valances) that were designed by Oliver Bulleid to aerofoil shape, and fitted to all the A4 locomotives, were removed during the Second World War to improve access to the valve gear for maintenance and were not replaced. This apart, the A4 was one of very few streamlined steam locomotive designs in the world to retain its casing throughout its existence.

World record

Plaque on Mallard in commemoration of breaking the world speed record of 126 mph

On 3 July 1938 4468 Mallard; the first of the class to enter service with the Kylchap exhaust, set a world speed record of 126 mph (202.8 km/h), pulling six coaches and a dynamometer car. Although the dynamometer car indicated a top speed of 126 mph (202.8 km/h), Gresley never accepted this as the record-breaking maximum. He claimed this speed could only have been attained over a few yards, though he was comfortable that the German speed record of 124.5 mph (200.4 km/h) had been surpassed.^{[citation needed]} Close analysis of the dynamometer roll (currently at the NRM) of the record run confirms that Mallard's speed did in fact exceed that of the German BR 05 002(Speed on the East Coast Mainline p64, P Semmens). The Mallard record reached its maximum speed on a downhill run and actually failed technically in due course, whereas 05 002's journey was on level grade and the engine did not yet seem to be at its limit, though on the other hand the German train was only four coaches long (197 tons), whilst Mallard`s train was seven coaches (240 tons).^{[citation needed]} One fact that is often ignored when considering rival claims is that Gresley and the LNER had just one serious attempt at the record, which was far from a perfect run with a 15mph permanent way check just North of Grantham. Despite this a record was set. Gresley planned to have another attempt in September 1939, but this was prevented by the outbreak of World War II. Prior to the record run on 3 July 1938, it was calculated that 130 mph (210 km/h) was possible, and in fact Driver Duddington and LNER Inspector Sid Jenkins both said they may well have achieved this figure had they not had to slow for the Essendine junctions.

At the end of Mallard's record run, the middle big end (part of the motion for the inside cylinder) was found to have run hot (indicated by the bursting of a heat-sensitive "stink bomb" placed in the bearing for warning purposes), the bearing metal having melted, which meant that the locomotive had to stop at Peterborough rather than continue on to London. Deficiencies in the alignment of the Gresley-Holcroft derived motion meant that the inside cylinder of the A4 did more work at high speed than the two outside cylinders - indeed on at least one occasion this led to the middle big end wearing to such an extent that the increased piston travel knocked the ends off the middle cylinder - and this overloading was mostly responsible for the failure.^{[citation needed]}

Performance in service

No other British steam locomotives have a longer or more consistent record of high speed running than the A4s, instances of 100 mph running by them must exceed those of all other types combined, though it must be stressed that even 90 mph running was a relatively rare event with steam traction, much less 100 mph. It should also be remembered that A4s operated on the East Coast Main Line which has more opportunities for high speed running (particularly Stoke Bank) than any other in the UK.

In August 1936 the Silver Jubilee train on the descent of Stoke Bank headed by 2512 Silver Fox driven by George Henry Haygreen achieved a maximum of 113 mph (181.9 km/h), then the highest speed attained in Britain with an ordinary passenger train.^{[citation needed]} The fastest recorded post war speed with British steam was also recorded by an A4. This occurred on the 23 May 1959 on the Stephenson Locomotive Society Golden Jubilee special when 60007 achieved 112 mph whilst hauling 400 tons down Stoke Bank. The driver was Bill Hoole and he had hoped for an attempt to beat Mallard's record but Alan Pegler, who was on the footplate and mindful of the risks, told him to ease off.

Although A4s were primarily designed for high speed express work they were also capable of high power outputs. In 1940 Capercaillie (4901) exerted 2200 drawbar horse power on the level York plain whilst hauling 21 coaches (730 tons gross) at an average of 75.9 mph for 25 miles. The highest recorded power output from an A4 was 2450 drawbar horspower when Mallard herself was hauling 11 coaches (390 tons gross) up Stoke Bank at a sustained 80 mph in 1963. O.S. Nock thought this performance superior to Mallard's world record run in 1938. To put all this in perspective the highest possible drawbar horsepower from a Class 40 diesel, which were supposed to replace the A4s, was 1450, though they could achieve this figure over long distances and with no effort from the crew.

Post-war history

No. 60034 Lord Faringdon hauling a train at Peterborough railway station in 1959.

Although newer Pacifics had been introduced since the war, and although the streamlined trains were never reinstated, the A4s continued on top link duties, notable on the London to Edinburgh services.

Improved methods of aligning the Gresley conjugated valve gear in the 1950s led to tighter tolerances for the bearings used within it and consequently to almost total eradication of the overloading of the middle cylinder.^{[citation needed]} History repeated itself with the inside big end being replaced by one of the Great Western type, after which there was no more trouble, provided maintenance routines were respected.

The wholesale application of double Kylchap chimneys to the entire class was entirely due to the persistence of P N Townend, the Assistant Motive Power Superintendent at King's Cross from 1956. He at first met with considerable resistance from higher authority. When permission was eventually given, it was found that the economy obtained over the single chimney A4s was from 6-7 pounds of coal per mile, which more than justified the expense of the conversion.

These improvements led to greatly increased availability.

Locomotive data

LNER Number (Intermediate Number)	British Railways Number	Doncaster Works number	Original Name (Rename(s))	Entered Service	Withdrawn
2509	60014	1818	Silver Link	01935-09-077 September 1935	01962-12-2929 December 1962
2510	60015	1819	Quicksilver	01935-09-2121 September 1935	01963-04-2525 April 1963
2511	60016	1821	Silver King	01935-11-055 November 1935	01965-03-1919 March 1965
2512	60017	1823	Silver Fox	01935-12-1818 December 1935	01963-10-2020 October 1963
4482	60023	1847	Golden Eagle	01936-12-2222 December 1936	01964-10-3030 October 1964
4483 (585)	60024	1848	Kingfisher	01936-12-2626 December 1936	01966-09-055 September 1966
4484 (586)	60025	1849	Falcon	01937-01-2323 January 1937	01963-10-2020 October 1963
4485 (587)	60026	1850	Kestrel (Miles Beevor from November 1947)	01937-03-2020 March 1937	01965-12-2121 December 1965
4486 (588)	60027	1851	Merlin	01937-03-1313 March 1937	01965-09-033 September 1965
4487	60028	1852	Sea Eagle (Walter K. Whigham from October 1947)	01937-03-2020 March 1937	01962-12-2929 December 1962
4488	60009	1853	Union of South Africa	01937-06-2929 June 1937	01966-06-011 June 1966
4489	60010	1854	Dominion of Canada	01937-05-044 May 1937	01965-05-2929 May 1965
4490	60011	1855	Empire of India	01937-06-2525 June 1937	01964-05-1111 May 1964
4491	60012	1856	Commonwealth of Australia	01937-06-2222 June 1937	01964-08-2020 August 1964
4492	60013	1857	Dominion of New Zealand	01937-06-2727 June 1937	01963-04-1818 April 1963
4493	60029	1858	Woodcock	01937-07-2626 July 1937	01963-10-2020 October 1963
4494	60003	1859	Osprey (Andrew K. McCosh from October 1942)	01937-08-1212 August 1937	01962-12-2929 December 1962
4495	60030	1860	Great Snipe (I) (Golden Fleece from September 1937)	01937-08-3030 August 1937	01962-12-2929 December 1962
4496	60008	1861	Golden Shuttle (Dwight D. Eisenhower from September 1945)	01937-09-044 September 1937	01963-07-2020 July 1963
4497	60031	1862	Golden Plover	01937-10-022 October 1937	01965-10-2929 October 1965
4498	60007	1863	Sir Nigel Gresley	01937-10-3030 October 1937	01966-02-011 February 1966
4462	60004	1864	Great Snipe (II) (William Whitelaw from July 1941)	01937-12-1010 December 1937	01966-07-1717 July 1966
4463	60018	1865	Sparrow Hawk	01937-11-2727 November 1937	01963-06-1919 June 1963
4464	60019	1866	Bittern	01937-12-1818 December 1937	01966-09-055 September 1966
4465	60020	1867	Guillemot	01938-01-088 January 1938	01964-03-2020 March 1964
4466 (605)	60006	1868	Herring Gull (Sir Ralph Wedgwood (II) from January 1944)	01938-01-2626 January 1938	01965-09-033 September 1965
4467	60021	1869	Wild Swan	01938-02-1919 February 1938	01963-10-2020 October 1963
4468	60022	1870	Mallard	01938-03-033 March 1938	01963-04-2525 April 1963
4469	—	1871	Gadwall (Sir Ralph Wedgwood (I) from March 1939)	01938-08-3030 August 1938	01942-06-066 June 1942
4499	60002	1872	Pochard (Sir Murrough Wilson from April 1939)	01938-04-1212 April 1938	01964-05-044 May 1964
4500	60001	1873	Garganey (Sir Ronald Matthews from March 1939)	01938-04-2626 April 1938	01964-10-1212 October 1964
4900	60032	1874	Gannet	01938-05-1717 May 1938	01963-10-2020 October 1963
4901	60005	1875	Capercaillie (Charles H. Newton from September 1942) (Sir Charles Newton from June 1943)	01938-06-088 June 1938	01964-03-1212 March 1964
4902	60033	1876	Seagull	01938-06-2828 June 1938	01963-12-2929 December 1963
4903	60034	1877	Peregrine (Lord Faringdon from March 1948)	01938-07-011 July 1938	01966-08-2424 August 1966

The first four locomotives included the word 'silver' in their names because they were intended to haul the 'Silver Jubilee' train. No 2512 Silver Fox of this batch carried a stainless-steel fox near the centre of the streamline casing on each side, made by the Sheffield steelmakers Samuel Fox and Company. The next batch of A4s were named after birds, particularly those that were fast flyers, Gresley being a keen bird-watcher. Five (4488–92) were named after British Empire countries to haul the new Anglo-Scottish 'Coronation' train; and two (4495/6), intended to haul the new 'West Riding Limited', received names connected to the wool trade: Golden Fleece and Golden Shuttle.

A rare gathering of three ex-LNER A4 locomotives at Grosmont, North Yorkshire Moors Railway, 60009 Union of South Africa, 60007 Sir Nigel Gresley and 60019 Bittern line up alongside each other

A4 No.4498 was the hundredth Gresley Pacific to be built and someone had the idea of naming it after the designer himself. This started a rash of renamings of other A4s, usually of directors of the LNER and many of the more obscure bird names (and a few of the better ones: Kestrel, Osprey for example) were exchanged for somewhat less inspiring names.^{[citation needed]}

One locomotive was withdrawn after being damaged beyond repair in a German bombing raid on York on 29 April 1942 during World War II - No.4469 Sir Ralph Wedgwood, which at the time had been overhauled and was based at Gateshead. It was running local trains to run it in, and was stabled in York North Shed (now the National Railway Museum) where it suffered a direct hit. However, its tender survived and was later coupled to a Thompson A2/1.

The first five withdrawals, in December 1963, were 60014 Silver Link, 60028 Walter K. Whigham, 60003 Andrew K. McCosh, 60030 Golden Fleece and 60033 Seagull. The rest of the class was withdrawn between 1963 and 1966. The last six in service were: 60004 William Whitelaw, 60007 Sir Nigel Gresley, 60009 Union Of South Africa, 60019 Bittern, 60024 Kingfisher and 60034 Lord Faringdon. 60019 and 60024 were the last to be withdrawn, in September 1966.

Preservation

Six of the locomotives have been preserved, four of them in the U.K and have run on the BR main lines at some point during their preservation career. Another two have been preserved in the U.S.A and Canada, rather appropriately due to their names. Both North American-based A4s are due to move to the National Railway Museum, York, in late 2012 on three-year loans.

Image	Numbers			Name	Current location	Condition
	Original LNER Number	LNER 1946	BR Number
	4464	19	60019	Bittern	Southall Currently at Severn Valley Railway	Approved for mainline use In LNER Livery and number
	4468	22	60022	Mallard	National Railway Museum	Static display (operational during late 1980s for two years)
	4488	9	60009	Union of South Africa	Crewe Heritage Centre	Nearing Completion of major overhaul
	4489	10	60010	Dominion of Canada	Canadian Railway Museum	Static display
	4496	8	60008	Dwight D Eisenhower	National Railroad Museum, Green Bay, Wisconsin	Static display
	4498	7	60007	Sir Nigel Gresley	North Yorkshire Moors Railway	Approved for main-line use In BR Blue with BR Number

In popular culture

A4s have appeared numerous times in popular culture, both during and after preservation. The class's first film appearance was 2509 Silver Link in the Will Hay film Oh! Mr. Porter, in which Hay accidentally ruins its naming ceremony. Post war, 60017 Silver Fox features heavily in the 1954 British Transport Film Elizabethan Express, which follows the revival of non-stop London to Edinburgh runs and features footage of the water trough and corridor tender in use. A few years later, the 1959 version of The Thirty-Nine Steps features colour photography of 60010 Dominion of Canada amongst others in their post-war British Railways Brunswick green livery. This scene was subsequently parodied in the 1961 film Carry on Regardless.

In The Railway Series books by the Rev. W Awdry, the 4468 Mallard is alluded to in the book Gordon the High Speed Engine by Christopher Awdry as one of Gordon's "Doncaster cousins" who did 126 miles an hour. Mallard appears as a character in the later book Thomas and the Great Railway Show. In the subsequent television series Thomas and Friends, the A4-based character Spencer, appears occasionally. Spencer bears a strong resemblance to Silver Link and is portrayed as a rather snooty character. Olwin from the children's series, Chuggington, resembles an A4 minus the tender making her a tank engine. A painting of 22 Mallard by Paul Gribble appears on the cover of the 1993 Blur album Modern Life is Rubbish.

Models

The distinctive shape of the A4 has made it an obvious choice for model manufacturers, with examples being made in the majority of the popular scales, including a wooden example for the Brio wooden railway. One of the first two Hornby Dublo locomotive models produced, in 1938, was an A4, and in 2004^{[citation needed]} Hornby produced an 'OO'-scale live steam version, that used an electrically-heated boiler to produce steam – not previously possible in such a small model. Trix produced an OO gauge model A4 from 1970; it was re-branded as a Liliput model in 1974 and survives to this day in modified form as a Bachmann model - Kader, Bachmann's parent company, had bought Liliput in 1993.

References

• Boddy, M.G.; Fry, E.V.; Hennigan, W.; Proud, P.; Yeadon, W.B. (July 1963). Fry, E.V.. ed. Locomotives of the L.N.E.R., part 1: Preliminary Survey. Potters Bar: RCTS. 
• Boddy, M.G.; Neve, E.; Yeadon, W.B. (April 1973). Fry, E.V.. ed. Locomotives of the L.N.E.R., part 2A: Tender Engines - Classes A1 to A10. Kenilworth: RCTS. ISBN 0-901115-25-8. 

External links

• LNER Encyclopedia Page covering the history and development of the LNER A4 Pacifics
• Detailed list of the names, numbers and production dates of LNER A4 locomotives
• Railuk database
• Screenshots from Elizabethan Express

Video links

• 1935, Demonstration run of 'Silver Jubilee' to Grantham
• 1944, Retirement of driver Duddington