GWR 4073 Class
Encyclopedia
The GWR 4073 Class or Castle class locomotives are a group of 4-6-0
steam locomotive
s of the Great Western Railway
. They were originally designed by the railway's Chief Mechanical Engineer, Charles Collett, for working the company's express passenger trains.
, 171 Castles were built, over a 27-year span from August 1923 to August 1950. They were numbered 4073–4099; 5000–5099; 7000–7037.
Although most were built new, 16 locos were rebuilt from older locomotives— 15 Star Class
locomotives; and the Great Western Railway's sole 4-6-2
locomotive, number 111 The Great Bear
.
The Castle class was noted for superb performance overall, and notably on the Cheltenham Flyer
during the 1930s: for example, on 6 June 1932 the train, pulled by 5006 Tregenna Castle, covered the 77.25 miles from Swindon
to Paddington
at an average speed of 81.68 mph start-to-stop (124.3 km at an average speed of 131.4 km/h). This world record for steam traction was widely regarded as an astonishing feat.
The origins of this highly successful design date back to G. J. Churchward’s Star Class of 1907. Stars were 4 cylinder 4-6-0s with long-travel valves and Belpaire fireboxes, and were an immediate success on the GWR’s top-link express duties to the west of England. However, with increasing loads the Stars had little in reserve to maintain the restored pre–World War One timings. C.B. Collett succeeded Churchward as Chief Mechanical Engineer of the GWR in 1922 and immediately faced the task of providing more power with little possibility of increasing axle weight. Thus the Castle class was born. When introduced they were heralded as Britain’s most powerful express passenger locomotive, being some 10% more powerful than the Stars. The Castle class locomotives had a larger boiler and cylinder bores were increased from 15 to 16 inches diameter. The first, No. 4073 Caerphilly Castle, made its debut at Paddington station on August 23, 1923.
During 1924 Caerphilly Castle was exhibited at The British Empire Exhibition, Wembley, alongside Sir Nigel Gresley’s Flying Scotsman. The Great Western engine was declared to be more powerful than its bigger LNER rival. During the subsequent ‘Locomotive Interchange Trials’ between the GWR and LNER No. 4079 Pendennis Castle operated on the East Coast Main line alongside Gresley pacifics; while LNER 4474 Victor Wild was sent to work between Paddington and Plymouth alongside No. 4074 Caldicot Castle. All locomotives acquitted themselves well but the compact Castle class demonstrated their superior fuel and water efficiency.
In 1926, number 5000 Launceston Castle was loaned to the London, Midland and Scottish Railway
where it ran trials between London and Carlisle. The locomotive fulfilled the LMS requirements so well that the latter first requested the GWR to build a batch of Castles for use on the West Coast Main Line, and, failing that, a full set of construction drawings. Both proposals were rejected by the GWR Board of Directors. The LMS eventually succeeded in gaining access to the design by recruiting William Stanier
, the GWR's Works Manager at their main Swindon railway works to become the new Chief Mechanical Engineer
for the LMS.
So successful was the Castles' design that construction continued at intervals until 1950, by which time 171 had been built. This included 15 converted from the Star class, plus the rebuilding of The Great Bear, the Great Western’s only Pacific locomotive.
In 1946 Frederick Hawksworth
, Collett’s successor, introduced a higher degree of superheat to the Castle boiler with resulting increased economy in water consumption. From 1956 the fitting of double chimneys to selected engines, combined with larger superheaters, further enhanced their capacity for sustained high-speed performance. In 1958 No. 7018 Drysllwyn Castle, fitted with a double chimney and a four row superheater, hauled ‘The Bristolian’ express at 100 mph at Little Somerford.
The Castles handled all but the heaviest loads, these being entrusted to the 30-strong King Class
. The Kings were themselves a development of the Castles, with an even larger boiler and slightly smaller wheels for increased tractive effort.
Withdrawal started in the 1950s; the last to be withdrawn was Clun Castle
at the end of 1965, which worked the last steam train out of Paddington in 1965. However, with preservation, that was not the end of the story for this long lived and popular class of express locomotives. On 4 March 1967 Clun Castle and No. 4079 Pendennis Castle hauled specials from Banbury and Oxford respectively to Chester, to mark the end of through trains between Paddington and Birkenhead.
4-6-0
Under the Whyte notation for the classification of steam locomotives, 4-6-0 represents the wheel arrangement of four leading wheels on two axles in a leading truck, six powered and coupled driving wheels on three axles, and no trailing wheels. This wheel arrangement became the second-most popular...
steam locomotive
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...
s of the Great Western Railway
Great Western Railway
The Great Western Railway was a British railway company that linked London with the south-west and west of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament in 1835 and ran its first trains in 1838...
. They were originally designed by the railway's Chief Mechanical Engineer, Charles Collett, for working the company's express passenger trains.
History
A development of the earlier Star ClassGWR 4000 Class
A Star class locomotive was a particular type of steam locomotive of the Great Western Railway. The prototype was an experimental locomotive, North Star , constructed with the 'Atlantic' 4-4-2 wheel arrangement for comparative trials with 4-cylinder compound locomotives of the de Glehn type that...
, 171 Castles were built, over a 27-year span from August 1923 to August 1950. They were numbered 4073–4099; 5000–5099; 7000–7037.
Although most were built new, 16 locos were rebuilt from older locomotives— 15 Star Class
GWR 4000 Class
A Star class locomotive was a particular type of steam locomotive of the Great Western Railway. The prototype was an experimental locomotive, North Star , constructed with the 'Atlantic' 4-4-2 wheel arrangement for comparative trials with 4-cylinder compound locomotives of the de Glehn type that...
locomotives; and the Great Western Railway's sole 4-6-2
4-6-2
4-6-2, in the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of four leading wheels on two axles , six powered and coupled driving wheels on three axles, and two trailing wheels on one axle .These locomotives are also known as Pacifics...
locomotive, number 111 The Great Bear
GWR 111 The Great Bear
The Great Bear, number 111, was a locomotive of the Great Western Railway. It was the first 4-6-2 Pacific locomotive used on a railway in Great Britain, and the only one of that type ever built by the GWR.- History and operation :...
.
The Castle class was noted for superb performance overall, and notably on the Cheltenham Flyer
Cheltenham Spa Express
The Cheltenham Spa Express is a British named passenger train service from Paddington station, in London, to Cheltenham Spa, in Gloucestershire, via Reading, Kemble, Stroud, Stonehouse and Gloucester...
during the 1930s: for example, on 6 June 1932 the train, pulled by 5006 Tregenna Castle, covered the 77.25 miles from Swindon
Swindon
Swindon is a large town within the borough of Swindon and ceremonial county of Wiltshire, in South West England. It is midway between Bristol, west and Reading, east. London is east...
to Paddington
Paddington
Paddington is a district within the City of Westminster, in central London, England. Formerly a metropolitan borough, it was integrated with Westminster and Greater London in 1965...
at an average speed of 81.68 mph start-to-stop (124.3 km at an average speed of 131.4 km/h). This world record for steam traction was widely regarded as an astonishing feat.
The origins of this highly successful design date back to G. J. Churchward’s Star Class of 1907. Stars were 4 cylinder 4-6-0s with long-travel valves and Belpaire fireboxes, and were an immediate success on the GWR’s top-link express duties to the west of England. However, with increasing loads the Stars had little in reserve to maintain the restored pre–World War One timings. C.B. Collett succeeded Churchward as Chief Mechanical Engineer of the GWR in 1922 and immediately faced the task of providing more power with little possibility of increasing axle weight. Thus the Castle class was born. When introduced they were heralded as Britain’s most powerful express passenger locomotive, being some 10% more powerful than the Stars. The Castle class locomotives had a larger boiler and cylinder bores were increased from 15 to 16 inches diameter. The first, No. 4073 Caerphilly Castle, made its debut at Paddington station on August 23, 1923.
During 1924 Caerphilly Castle was exhibited at The British Empire Exhibition, Wembley, alongside Sir Nigel Gresley’s Flying Scotsman. The Great Western engine was declared to be more powerful than its bigger LNER rival. During the subsequent ‘Locomotive Interchange Trials’ between the GWR and LNER No. 4079 Pendennis Castle operated on the East Coast Main line alongside Gresley pacifics; while LNER 4474 Victor Wild was sent to work between Paddington and Plymouth alongside No. 4074 Caldicot Castle. All locomotives acquitted themselves well but the compact Castle class demonstrated their superior fuel and water efficiency.
In 1926, number 5000 Launceston Castle was loaned to the London, Midland and Scottish Railway
London, Midland and Scottish Railway
The London Midland and Scottish Railway was a British railway company. It was formed on 1 January 1923 under the Railways Act of 1921, which required the grouping of over 120 separate railway companies into just four...
where it ran trials between London and Carlisle. The locomotive fulfilled the LMS requirements so well that the latter first requested the GWR to build a batch of Castles for use on the West Coast Main Line, and, failing that, a full set of construction drawings. Both proposals were rejected by the GWR Board of Directors. The LMS eventually succeeded in gaining access to the design by recruiting William Stanier
William Stanier
Sir William Arthur Stanier, FRS was Chief Mechanical Engineer of the London, Midland and Scottish Railway.- Biography :...
, the GWR's Works Manager at their main Swindon railway works to become the new Chief Mechanical Engineer
Chief Mechanical Engineer
Chief Mechanical Engineer and Locomotive Superintendent are titles applied by British, Australian, and New Zealand railway companies to the person ultimately responsible to the board of the company for the building and maintaining of the locomotives and rolling stock...
for the LMS.
So successful was the Castles' design that construction continued at intervals until 1950, by which time 171 had been built. This included 15 converted from the Star class, plus the rebuilding of The Great Bear, the Great Western’s only Pacific locomotive.
In 1946 Frederick Hawksworth
Frederick Hawksworth
Frederick W. Hawksworth , was Chief Mechanical Engineer of the Great Western Railway ....
, Collett’s successor, introduced a higher degree of superheat to the Castle boiler with resulting increased economy in water consumption. From 1956 the fitting of double chimneys to selected engines, combined with larger superheaters, further enhanced their capacity for sustained high-speed performance. In 1958 No. 7018 Drysllwyn Castle, fitted with a double chimney and a four row superheater, hauled ‘The Bristolian’ express at 100 mph at Little Somerford.
The Castles handled all but the heaviest loads, these being entrusted to the 30-strong King Class
GWR 6000 Class
The Great Western Railway 6000 Class or King is a class of 4-6-0 steam locomotive designed for express passenger work. With the exception of one Pacific , they were the largest locomotives the GWR built. They were named after kings of the United Kingdom and of England, beginning with the reigning...
. The Kings were themselves a development of the Castles, with an even larger boiler and slightly smaller wheels for increased tractive effort.
Withdrawal started in the 1950s; the last to be withdrawn was Clun Castle
GWR 4073 Class 7029 Clun Castle
7029 Clun Castle was built to the Great Western Railway Castle Class design by the Western Region of British Railways at Swindon Works in May 1950 and was named after Clun Castle. Its first shed allocation was Newton Abbot. It had a double chimney and a 4 row superheater fitted in October 1959...
at the end of 1965, which worked the last steam train out of Paddington in 1965. However, with preservation, that was not the end of the story for this long lived and popular class of express locomotives. On 4 March 1967 Clun Castle and No. 4079 Pendennis Castle hauled specials from Banbury and Oxford respectively to Chester, to mark the end of through trains between Paddington and Birkenhead.
Preservation
Eight Castles survive in preservation:| Number | Image | Name | Owner | Current location | Current status |
|---|---|---|---|---|---|
 |
GWR 4073 Class 4073 Caerphilly Castle Caerphilly Castle is a member of the GWR 4073 Class built in 1923. Its first shed allocation was Old Oak Common. Its August 1950 shed allocation was Bath Road, Bristol. Its last shed allocation was Cardiff Canton in March 1959... |
National Railway Museum The National Railway Museum is a museum in York forming part of the British National Museum of Science and Industry and telling the story of rail transport in Britain and its impact on society. It has won many awards, including the European Museum of the Year Award in 2001... |
Swindon Steam Railway Museum STEAM – Museum of the Great Western Railway, also known as Swindon Steam Railway Museum, is located at the site of the old railway works in Swindon, England – Wiltshire's 'railway town'... |
On static display | |
 |
GWR 4073 Class 4079 Pendennis Castle Pendennis Castle is a GWR 4073 Class steam locomotive, preserved at the Didcot Railway Centre.-Operations:The seventh of the first lot of 10 Castles built in 1923/4, No.4079 "Pendennis Castle" was completed at Swindon Works in February 1924... |
Didcot Railway Centre Didcot Railway Centre, located in the town of Didcot in the English county of Oxfordshire, is based around the site of a comprehensive "engine shed" which became redundant after the nationalisation of the UK railways, due to the gradual changeover from steam to diesel motive power.-Description:The... |
Under rebuild | ||
 |
GWR 4073 Class 5029 Nunney Castle 5029 Nunney Castle is a preserved GWR 4073 Class steam locomotive, built at Swindon in May 1934.Withdrawn in December 1963, it was sent to Woodham Brothers scrapyard in Barry, South Wales in May 1964..... |
Jeremy Hosking Jeremy J. Hosking is a British businessman, a co-founder and investment portfolio manager for private investment fund Marathon. Hosking is also well known for his extensive collection of steam locomotives, and 25% share holding in Crystal Palace F.C.... |
Operational, main line certified | ||
GWR 4073 Class 5043 Earl of Mount Edgcumbe The GWR 4073 Class 5043 Earl of Mount Edgcumbe is a steam locomotive of the GWR 'Castle' Class, built in March 1936. It was originally named Barbury Castle, and was renamed Earl of Mount Edgcumbe in September 1937... (Barbury Castle) |
Birmingham Railway Museum Tyseley Locomotive Works is the museum and engineering arm of the Birmingham Railway Museum Trust, based in Birmingham, England. It occupies part of the former Great Western Railway's depot, which was constructed in 1908 as a result of expanding operations in the West Midlands, particularly the... |
Operational, main line certified | |||
 |
GWR 4073 Class 5051 Earl Bathurst Earl Bathurst is a Castle class locomotive. It still works, and is run by the Didcot Railway Centre.It was originally built as Drysllwyn Castle in May 1936. Its first shed allocation was Swansea Landore. Renamed Earl Bathurst in August 1937; the name coming from a de-named GWR Dukedog Class. It... (Drysllwyn Castle) |
Didcot Railway Centre Didcot Railway Centre, located in the town of Didcot in the English county of Oxfordshire, is based around the site of a comprehensive "engine shed" which became redundant after the nationalisation of the UK railways, due to the gradual changeover from steam to diesel motive power.-Description:The... |
On static display | ||
 |
GWR 4073 Class 5080 Defiant Originally built as Ogmore Castle in May 1939 at Swindon Works, the engine was one of the many popular GWR Castle Class.After transfer to Cardiff , the engine was renamed Defiant in January 1941, commemorating one of the many types of aircraft which had taken part in the Battle of Britain... (Ogmore Castle) |
Birmingham Railway Museum Tyseley Locomotive Works is the museum and engineering arm of the Birmingham Railway Museum Trust, based in Birmingham, England. It occupies part of the former Great Western Railway's depot, which was constructed in 1908 as a result of expanding operations in the West Midlands, particularly the... |
Buckinghamshire Railway Centre Buckinghamshire Railway Centre is a railway museum operated by the Quainton Railway Society Ltd. at Quainton Road railway station, in the far depths of "Metro-land", about 5 miles west of Aylesbury in Buckinghamshire. The site is divided into two halves which are joined by two foot-bridges, one of... |
On static display | |
GWR 4073 Class 7027 Thornbury Castle 7027 Thornbury Castle was built in August 1949. Its first shed allocation was Plymouth Laira. Its March 1959 shed allocation was Old Oak Common. Its last shed allocation was Reading. It was withdrawn in December 1963 and arrived at Woodham Brothers scrapyard in Barry, South Wales in May 1964... |
Pete Waterman Peter Alan Waterman OBE is an English record producer, occasional songwriter, radio and club DJ, television presenter, president of Coventry Bears rugby league club and a keen railway enthusiast. As a member of the Stock Aitken Waterman songwriting team he wrote and produced many hit singles... |
Stored awaiting restoration | |||
GWR 4073 Class 7029 Clun Castle 7029 Clun Castle was built to the Great Western Railway Castle Class design by the Western Region of British Railways at Swindon Works in May 1950 and was named after Clun Castle. Its first shed allocation was Newton Abbot. It had a double chimney and a 4 row superheater fitted in October 1959... |
Birmingham Railway Museum Tyseley Locomotive Works is the museum and engineering arm of the Birmingham Railway Museum Trust, based in Birmingham, England. It occupies part of the former Great Western Railway's depot, which was constructed in 1908 as a result of expanding operations in the West Midlands, particularly the... |
Under overhaul |