Editing GWR 4073 Class

{{Short description|Class of 171 four-cylinder 4-6-0 locomotives}}
{{Use dmy dates|date=April 2024}}
{{Use British English|date=May 2013}}
{{Infobox locomotive
| name = GWR 4073 ''Castle'' class
| powertype = Steam
| image = File:GWR_4079_Pendennis_Castle_Didcot_Railway_Centre_4th_March_2023.jpg
| caption = 4079 ''Pendennis Castle'' at Didcot Railway Centre in 2023
| designer = [[Charles Collett]]
| builder = GWR / BR [[Swindon Works]]
| builddate = 1923–1950
| ordernumber = Lots 224, 232, 234, 280, 295, 296, 303, 310, 317, 324, 357, 367, 375
| totalproduction = 171
| gauge = {{Track gauge|ussg|allk=on}}
| whytetype = {{whyte|4-6-0}}
| uicclass = 2′C h4
| leadingdiameter = {{convert|3|ft|2|in|m|3|abbr=on}}
| driverdiameter = {{convert|6|ft|8+1/2|in|m|3|abbr=on}}
| minimumcurve = {{convert|8|chain|ft m}} normal,<br/>{{convert|7|chain|ft m}} slow
| length = {{convert|65|ft|2|in|m|2|abbr=on}} over [[buffer (rail transport)|buffers]]
| width = {{convert|8|ft|11|in|m|3|abbr=on}}
| height = {{convert|13|ft|4+1/2|in|m|3|abbr=on}}
| axleload = {{long ton|19|14}}<br/>{{convert|19|LT|14|lcwt|ST|disp=output only}} full
| weightondrivers = {{long ton|58|17}}<br/>{{convert|58|LT|17|lcwt|ST|disp=output only}} full
| locoweight = {{long ton|79|17}}<br/>{{convert|79|LT|17|lcwt|ST|disp=output only}} full
| tenderweight = {{long ton|47|6}}<br/>{{convert|47|LT|6|lcwt|ST|disp=output only}} full
| fueltype = [[Coal]]
| fuelcap = {{ubl|Churchward tender: {{convert|7|LT|t ST|1|abbr=on}}|Collett/Hawksworth tender: {{convert|6|LT|t ST|1|abbr=on}}}}
| watercap = Churchward tender: {{ubl|{{convert|3500|impgal|abbr=on}}|Collett/Hawksworth tender: {{convert|4000|impgal|abbr=on}}}}
| boilerpressure = {{convert|225|lbf/in2|MPa|2|abbr=on}}
| firearea = {{convert|29.36|sqft|m2|abbr=on}}
| boiler = GWR Standard No. 8{{sfnb|Champ|2018|p=320}}
| tubearea = {{ubl|{{convert|1857.7|sqft|m2|abbr=on}} (Collett)|{{convert|1799.5|sqft|m2|abbr=on}} (Hawksworth)}}
| fireboxarea = {{ubl|{{convert|162.7|sqft|m2|abbr=on}} (Collett)|{{convert|163.5|sqft|m2|abbr=on}} (Hawksworth)}}
| superheatertype = {{ubl|14-element "Swindon" (Collett)|21-element (Hawksworth)}}
| superheaterarea = {{ubl|{{convert|262.6|sqft|m2|abbr=on}} (Collett)|{{convert|295.0|sqft|m2|abbr=on}} (Hawksworth)}}
| cylindercount = Four (two inside, two outside)
| cylindersize = {{convert|16|x|26|in|mm|0|abbr=on}}
| valvegear = {{ubl|Inside cylinders: [[Walschaerts valve gear|Walschaerts]]|Outside cylinders: derived from inside cylinders via rocking bars.}}
| valvetype = [[Piston valve (steam engine)|Piston valves]]
| tractiveeffort = {{convert|31625|lbf|kN|2|abbr=on|lk=on}}
| operator = {{ubl|[[Great Western Railway]]|[[British Rail]]ways}}
| fleetnumbers = 4073–4099; 5000–5099; 7000–7037.
| powerclass = {{ubl|[[Great Western Railway Power Classification|GWR: D]]|BR: 7P}}
| axleloadclass = [[Great Western Railway Weight Classification|GWR: Red]]
| locale = [[Great Western Main Line]]
| withdrawndate = May 1950 to December 1965
| disposition = Eight preserved, remainder [[scrap]]ped
}}

The '''4073''' or '''Castle Class''' are [[4-6-0]] [[steam locomotive]]s of the [[Great Western Railway]], built between 1923 and 1950.{{sfnb |Nock |1980 |p=11}} They were designed by the railway's Chief Mechanical Engineer, [[Charles Collett]], for working the company's express passenger trains.<ref>{{Cite news |last=Bestwick |first=Alex |date=2024-01-08 |title=The history of GWR's 'Castle' Class, from design to preservation {{!}} The Railway Magazine |url=https://www.railwaymagazine.co.uk/27116/the-history-of-gwrs-castle-class-from-design-to-preservation/ |archive-url=http://web.archive.org/web/20240613212147/https://www.railwaymagazine.co.uk/27116/the-history-of-gwrs-castle-class-from-design-to-preservation/ |archive-date=2024-06-13 |access-date=2024-12-26 |language=en-GB}}</ref> They could reach speeds of up to {{cvt|100|mph}}.{{sfnb|Black|2017|p=45}}

==Background==
The origins of this highly successful design date back to the [[GWR 4000 Class|Star Class]] of 1907 which introduced the basic 4-cylinder 4-6-0 layout with long-travel valves and [[Belpaire firebox]] that was to become characteristic of [[Great Western Railway]] (GWR) express passenger locomotives. The Star class was designed to take the top express trains on the GWR, with 61 in service by 1914, but after [[World War I]] there was a need for an improved design. To meet this need, Chief Mechanical Engineer [[George Churchward]] had in mind an enlarged Star class design with a standard No.7 boiler, as fitted to his [[GWR 4700 Class]] express freight 2-8-0.{{sfnb |le Fleming|1953 |p=H13}} However, this combination would have taken the axle load over the 20-ton limit then set by the civil engineers, and in the end, nothing came of the idea.

==Design==
[[Charles Collett]] succeeded Churchward as Chief Mechanical Engineer of the GWR in 1922 and immediately set about meeting the need for a new locomotive design that would both supplement the Stars and replace them on the heaviest expresses. Collett's solution was to take the basic layout of the Star with an extended frame, and add a newly designed No.8 boiler which was both larger and lighter.{{sfnb|Nock|1980|p=92}} The increased amount of steam that this produced allowing an increase in the cylinder diameter from {{convert|15|x|26|in|mm|0|abbr=on}} to {{convert|16|x|26|in|mm|0|abbr=on}}. The extended frame allowed for a side window cab and an increased grate area. The result was an increase in tractive effort to 31,625&nbsp;lb, and a locomotive that looked attractive and well proportioned while remaining within the 20-ton axle limit.

==Production==
Unlike the Star class, there was no prototype. Collett was sufficiently confident of the design to place an order with [[Swindon Works]] (Lot 224) for ten locomotives in 1923, although there was a four-month delay between the appearance of the first example in August 1923 and the second in December, to allow for the correction of any teething problems.{{sfnb |le Fleming|1953 |p=H17}} Thereafter the remaining eight locomotives came out at regular intervals until April 1924. They were 4073–4082, the number series continuing unbroken from the Star class. The last 12 Star class locomotives, which were built in 1922–23, had been given names of abbeys in the western area served by the GWR. The new locomotives were named after castles, also in the west, beginning with ''[[GWR 4073 Class 4073 Caerphilly Castle|Caerphilly Castle]]''.

Over the twenty-seven years from August 1923 to August 1950, 155 Castles were built new at Swindon Works and a further sixteen were converted from other classes. In February 1952, two engines, 4082 ''Windsor Castle'' and 7013 ''Bristol Castle'', swapped names and numbers: 7013 was disguised as 4082 to run [[George VI]]'s funeral train and the numbers were never swapped back. 4082 was withdrawn from service in 1964 as 7013 and 7013 was withdrawn from service as 4082 in 1965.

===New builds===
The new-builds were as follows.{{sfnb |le Fleming|1953 |p=H17–H18}}

Great Western Railway
*Lot 224: Nos. 4073–4082, delivered August 1923 to April 1924.
*Lot 232: Nos. 4083–4092, delivered May to August 1925.
*Lot 234: Nos. 4093–4099 and 5000 to 5012, delivered May 1926 to July 1927.
*Lot 280: Nos. 5013–5022, delivered June to August 1932.
*Lot 295: Nos. 5023–5032, delivered June to August 1932.
*Lot 296: Nos. 5033–5042, delivered May to July 1933.
*Lot 303: Nos. 5043–5067, delivered March 1936 to July 1937. (Nos. 5043–5063 were originally named after Castles, but were renamed in 1937 after Earls)
*Lot 310: Nos. 5068–5082 delivered June 1938 to June 1939. (Nos. 5069 and 5070 were named after [[Isambard Kingdom Brunel]] and [[Daniel Gooch|Sir Daniel Gooch]]; In 1941 5071–5082 were renamed after aircraft used by the [[Royal Air Force]])
*Lot 324: Nos. 5093–5097, delivered June to July 1939.
*Lot 357: Nos. 5098–5099, 7000–7007 delivered May to July 1946.

[[Western Region of British Railways|British Railways (Western Region)]]
*Lot 367: Nos. 7008–7027, delivered May 1948 to August 1949.
*Lot 375: Nos. 7028–7037, delivered May 1950 to August 1950.
These locomotives were built with minimal changes to the dimensions. However, from 5013 ''Abergavenny Castle'' there was an alteration to the shape of the front-end casing over the inside cylinders, and from 5043 ''Earl of Mount Edgcumbe'' a shorter chimney was fitted.<ref name=KCGWR/> Those built before 1926 were fitted with a {{convert|3500|impgal|abbr=on}} tender but thereafter {{convert|4000|impgal|abbr=on}} became standard for the class.

===Rebuilds===
Between January and September 1924, the only Great Western [[4-6-2]], No.111 [[GWR 111 The Great Bear|The Great Bear]], was rebuilt into a member of the Castle Class, although only the "front portion of the original [[Locomotive frame|frames]] and the number plates were used again but probably little else". The new locomotive was renamed ''Viscount Churchill'' and survived until withdrawal in July 1953.{{sfnb |le Fleming|1953 |p=H13}}

In April 1925, Star class No. 4009 ''Shooting Star'' was likewise rebuilt as a Castle by extending the frames and fitting a new Castle Class boiler and cab. It was renumbered and renamed 100 A1 ''Lloyds'' and was withdrawn in 1950.{{sfnb |le Fleming|1953 |p=H17–H19}}

In October 1925 a second Star class, No. 4016 ''The Somerset Light Infantry (Prince Albert's)'', was similarly converted to a Castle although in this case, it retained its name and number.{{sfnb |le Fleming|1953 |p=H13}} Two further conversions of Stars were undertaken in 1926; Nos. 4032 ''Queen Alexandra'' and 4037 ''The South Wales Borderers'' retaining their names and numbers and surviving until 1951 and 1962 respectively.

In November 1929 the prototype for the Star Class, No. 4000 ''North Star'' was rebuilt into a Castle, being subsequently withdrawn in 1957.

Between 1937 and 1940 a further ten members of the 'Abbey series' of the Star class (Nos. 4063–4072) were rebuilt as Castles on Lot 317. They were allocated new numbers 5083 to 5092 but retained their original names and were withdrawn between 1958 and 1964.

==Publicity and trials==
[[File:GWR 4079 Pendennis Castle at Chester General.jpg|thumb|left|upright|alt=Pendennis Castle at Chester|[[GWR 4073 Class 4079 Pendennis Castle|4079 ''Pendennis Castle'']] at [[Chester railway station|Chester General station]] in March 1967]]
When introduced they were heralded as Britain's most powerful express passenger locomotive, being some 10% more powerful than the Stars. The first, No. 4073 ''Caerphilly Castle'', made its debut at [[Paddington railway station|Paddington station]] on 23 August 1923. The choice of 4082 as ''Windsor Castle'' proved fortuitous as this locomotive was used to haul the [[British Royal Train|Royal Train]] when King [[George V]] and [[Mary of Teck|Queen Mary]] visited Swindon Works in 1924, and much publicity was gained when the king was invited to drive the engine back from the works to the station before the return journey, with the Queen and several high-ranking GWR officers also on the footplate.<ref name=KCGWR>{{cite book |last = Nock |first = O.S. |author-link = Oswald Nock |title = Kings & Castles of the G.W.R. |publisher = [[Ian Allan Publishing]]|location = Shepperton |year = 1969 |edition = 2nd |isbn = 0-7110-0071-9}}</ref>

[[File:Castle class locos 5051 and 5029 climb St Germans bank - geograph.org.uk - 739097.jpg|thumb|Castle class locos [[GWR 4073 Class 5051 Earl Bathurst|5051 ''Earl Bathurst'']] and [[GWR 4073 Class 5029 Nunney Castle|5029 ''Nunney Castle'']] climb [[St Germans railway station|St Germans]] bank]]
[[File:Steaming through Dorchester West.ogv|thumb|[[GWR 4073 Class 5029 Nunney Castle|5029 ''Nunney Castle'']] steam special passing through [[Dorchester West railway station|Dorchester West]] in August 2011]]
During 1924, 4073 ''Caerphilly Castle'' was exhibited at the [[British Empire Exhibition]] at Wembley, alongside [[Nigel Gresley]]'s ''[[LNER Class A3 4472 Flying Scotsman|Flying Scotsman]]''.  The Great Western declared their engine to be more powerful than its bigger [[London & North Eastern Railway|LNER]] rival, and in terms of tractive effort alone they were entitled to do so.  As a result of this, GWR General Manager [[Felix Pole|Sir Felix Pole]] proposed to LNER Southern Area General Manager Alexander Wilson that a trial of the two types should take place via an exchange arrangement.<ref name=STTGW>{{cite book|last =Allen |first =Cecil J|author-link =Cecil J. Allen|title =Salute to the Great Western|publisher =Ian Allan|location =Shepperton|year =1970|isbn =0-7110-0181-2}}</ref> The resulting trials commenced in April 1925 with [[GWR 4073 Class 4079 Pendennis Castle|4079 ''Pendennis Castle'']] representing the GWR on the [[East Coast Main Line]] and 4474 ''Victor Wild'' representing the LNER on GWR tracks. On the first morning ''Pendennis Castle'' was to work a 480-ton train from [[London King's Cross railway station|King's Cross]] to [[Doncaster railway station|Doncaster]], and LNER officials fully expected the smaller, lighter engine to encounter problems climbing Holloway Bank. However, railway writer [[Cecil J. Allen]] records that the GWR locomotive made a faster start from King's Cross to [[Finsbury Park railway station|Finsbury Park]] than any LNER [[4-6-2|Pacific]] he had recorded up to that time,<ref name=STTGW/> and over the trial ''Pendennis Castle'' kept well within the scheduled time and used less coal, considerably denting LNER pride. For the LNER, ''Victor Wild'' was compared on the ''[[Cornish Riviera Express]]'' to 4074 ''Caldicot Castle'' and although it kept to time the longer wheelbase of the Pacific proved unsuited to the many curves on the route. Again the GWR took the honours with ''Caldicot Castle'' burning less fuel and always ahead of time, this being illustrated on the last 2 days of the trial by gaining 15 minutes on the schedule in both directions.<ref name=STTGW/>

In 1926, number 5000 ''Launceston Castle'' was loaned to the [[London, Midland & Scottish Railway]] (LMS) where it ran trials between [[Euston railway station|London]] and [[Carlisle railway station|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 its Swindon Works to become the new [[Chief Mechanical Engineer]] for the LMS.<ref name=Cook>{{cite book| page=52| title=Swindon Steam 1921–1951| year=1974| author=Kenneth J. Cook| publisher=Ian Allan| location=Staines, Middlesex }}</ref>

In 1935 attention was turning to streamlining locomotives, particularly with the introduction of the [[LNER Class A4|LNER A4]], and the GWR felt that they could gain publicity in this area. Instructions were passed to [[Swindon Works]] to select a suitable locomotive and as 5005 ''Manorbier Castle'' was being prepared for test, additions were made to the locomotive to effect some streamlining. The application of shaped steel sheet in an attempt to smooth airflow has been described as a "bodge-up" and certainly lacked either the elegance of the A4 design, or the sense of power associated with the streamlined [[LMS Coronation Class]] introduced 2 years later. Once the additions had been added a test run was carried out between Bristol and Swindon during which ''Manorbier Castle'' achieved a speed of 100&nbsp;mph, but the experiment did not have any lasting effect on GWR locomotive design and the additions were later removed.<ref>{{cite magazine| last = Bullock| first = William| date = August 1992| title = Swindon Apprentice| magazine = Steam World| issue = 62|location = Peterborough| publisher = EMAP Apex Publications| pages=30–33}}</ref>

==Performance==
The Castles handled all but the heaviest loads, these being entrusted to the 30-strong [[GWR 6000 Class|King Class]], themselves a development of the Castles with an even larger boiler and smaller wheels (6&nbsp;ft 6 in diameter) for both increased tractive effort and to allow for loading gauge clearance.

The Castle class was noted for superb performance overall, and notably on the ''[[Cheltenham Spa Express|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 railway station|Swindon]] to [[Paddington railway station|Paddington]] at an average speed of 81.68&nbsp;mph start-to-stop (124.3&nbsp;km at an average speed of 131.4&nbsp;km/h). This world record for steam traction was widely regarded as an astonishing feat.<ref name=KCGWR/>

==Subsequent modification== 
[[File:5043 Earl of Mount Edgcumbe parked up around the turntable.jpg|thumb|[[GWR 4073 Class 5043 Earl of Mount Edgcumbe|5043 ''Earl of Mount Edgcumbe'']] is one of two preserved Castles to be fitted with a [[double chimney]]]]
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 chimney]]s to selected engines, combined with larger superheaters, further enhanced their capacity for sustained high-speed performance. The fastest recorded speed of a Castle Class engine was 102&nbsp;mph achieved by 7018 ''Drysllwyn Castle'' at [[Little Somerford]] in April 1958 while hauling ''[[The Bristolian (train)|The Bristolian]]'' from [[Bristol Temple Meads railway station|Bristol]] to London. The non-stop run over 117.6 miles took 93 minutes 50 seconds, an average speed of more than 75&nbsp;mph.<ref>{{cite book|title=Great Western|last1=Allen|first1=Cecil|date=1962|publisher=Ian Allan|pages=64}}</ref>

=== Oil firing ===
{{Main|GWR oil burning steam locomotives}}
Between 1946 and 1948 five engines—100A1, 5039, 5079, 5083 and 5091—were converted to oil-firing, but were soon restored to burn coal. Eleven [[GWR 4900 Class|Halls]] were also temporarily converted.{{sfnb |Haresnape |1978 |pp=27, 33}}

==Accidents and incidents==
*On 2 July 1941, 4091 ''Dudley Castle'' was hauling an express passenger train that was in a head-on collision with a freight train, hauled by [[LMS Stanier 8F]] [[2-8-0]] No. WD 407 (LMS 8293), at {{rws|Slough}}, [[Berkshire]]. 5 people were killed and 21 were injured.<ref name=Earnshaw5>{{cite book |last=Earnshaw |first=Alan |title=Trains in Trouble: Vol. 5 |year=1989 |publisher=Atlantic Books |location=Penryn |isbn=0-906899-35-4 |page=29 }}</ref>
*On 30 November 1948, a passenger train hauled by 5022 ''Wigmore Castle'' [[signal passed at danger|overran signals]] and was in collision with [[GWR 5101 Class|locomotive 4150]], which was running round its train at {{rws|Lapworth}}.<ref name=SR455>{{cite magazine |title=Light at the end of the tunnel for Severn 'Prairie' |magazine=[[Steam Railway]] |publisher=Bauer Consumer Media Ltd |location=Peterborough |date=17 June 2016 |issue=455 |issn=0143-7232 |pages=40–42}}</ref> Eight passengers were injured.<ref name=Times011048>{{Cite newspaper The Times |title=Four killed and 50 injured in train crash |date=1 December 1948 |page=4 |issue=51243 |column=A-B }}</ref>
*On 12 November 1958, a freight train, hauled by [[GWR 4700 Class]] [[2-8-0]] No. 4707, overran signals and was derailed at Highworth Junction, [[Swindon]]. Locomotive No. 5009 ''Shrewsbury Castle'' was hauling a newspaper train which collided with the wreckage.<ref name=Trevena>{{cite book |last=Trevena |first=Arthur |title=Trains in Trouble |volume= 1 |year=1980 |publisher=[[Atlantic Books]] |location=Redruth |isbn=0-906899-01-X |page=47 }}</ref>

==Royal connections==
On 28 April 1924, King [[George V]] drove locomotive No. 4082 ''Windsor Castle'' from the Swindon Works to [[Swindon railway station]], accompanied on the footplate by [[Mary of Teck|Queen Mary]]. Plaques to commemorate the event were fixed to the sides of the cab and it was considered to be a royal locomotive from then onwards.<ref name="greatwestern">{{cite web |url=http://www.greatwestern.org.uk/m_in_cas_40827013.htm |title=Castle Class - Windsor Castle |last=Daniel |first=John |date= |website=www.greatwestern.org.uk |access-date=14 October 2022}}</ref> At the [[Death and state funeral of George V|king's state funeral]] on 28 January 1936, ''Windsor Castle'' was chosen to haul the [[funeral train]] from [[Paddington Station]] in London to [[Windsor & Eton Central railway station|Windsor & Eton]]. It was preceded at ten-minute intervals by another six trains hauled by Castle-class engines, each carrying royal and other important mourners.<ref>{{cite journal |author=<!--Not stated--> |date=15 February 1936 |title=Workings of Royal Special Trains in connection with the Funeral of the late King |url=https://www.steamindex.com/locomag/lcwr42.htm |journal=The Locomotive Magazine and Railway Carriage and Wagon Review |volume=42 |issue=522 |pages=42–43 |access-date=14 October 2022 |archive-date=28 January 2023 |archive-url=https://web.archive.org/web/20230128130700/https://steamindex.com/locomag/lcwr42.htm |url-status=dead }}</ref>

The same locomotive was requested for the [[Death and state funeral of George VI|funeral of King George VI]] in February 1952; however, ''Windsor Castle'' was under repair at Swindon, so the number, name plate and commemorative plaques were swapped with No. 7013 ''Bristol Castle'' for the event. Following the funeral, the two locomotives retained their exchanged names and numbers, but the commemorative plaques were returned. No. 7013 (originally 4082) was scrapped in September 1964 while number 4082 (originally 7013) survived until February 1965.<ref name="greatwestern"/>

==Withdrawal==
Withdrawal of steam power started in the 1950s, with the first 100 A1 ''Lloyds'' withdrawn from [[Old Oak Common TMD|Old Oak Common]] in March 1950. The first "new build" Castle, number 4091 ''Dudley Castle'', was withdrawn from Old Oak Common nearly nine years later in January 1959.

The lowest mileage of a Castle was the 580,346 miles run by 7035 ''Ogmore Castle'' between August 1950 and June 1964; the highest mileage of any Castle class was by 4080 ''Powderham Castle'' which totalled 1,974,461 miles in 40 years and 5 months.{{Citation needed|date=April 2022}}

The last three Castles to be withdrawn were all allocated to Gloucester shed,<ref name=SIAC>{{cite book |last = Waters |first = Laurence |title = Steam in Action 'Castles' |publisher = Ian Allan |location = Shepperton |year = 1991 |isbn = 0-7110-2006-X }}</ref> with 5042 ''Winchester Castle'' and 7022 ''Hereford Castle'' withdrawn in June 1965. The last to be withdrawn was [[GWR 4073 Class 7029 Clun Castle|7029 ''Clun Castle'']] in December 1965, which worked the last steam train out of Paddington on 27 November 1965.<ref>{{cite book|last =Riley|first =R.C.|title =Great Western Album|publisher =Ian Allan|location =Shepperton|year =1966|isbn =0-7110-0073-5}}</ref>

{|class="wikitable" style=text-align:center
|+ Table of withdrawals
! Year !! Number in<br/>service at<br/>start of year !! Number<br/>withdrawn !! Total<br/>withdrawn !! Locomotive numbers !! Notes
|-
| 1950 || 171 ||   1  ||   1 || align=left | 100A1 || 
|-
| 1951 || 170 ||   2  ||   3 || align=left | 4016/32 ||
|-
| 1953 || 168 ||  1   ||   4 || align=left | 111 ||
|-
| 1957 || 167 ||  1   ||   5 || align=left | 4000 ||
|-
| 1958 || 166 ||  1   ||   6 || align=left | 5086 ||
|-
| 1959 || 165 ||  3   ||   9 || align=left | 4091, 5010/83 ||
|-
| 1960 || 162 ||  7   ||  16 || align=left | 4073/84/97, 5005/09/28/79 || [[GWR 4073 Class 4073 Caerphilly Castle|4073]] preserved
|-
| 1961 || 155 ||  4   ||  20 || align=left | 4037/75/83/92 ||
|-
| 1962 || 151 ||  54  ||  74 || align=left | 4077–78/85–86/94–95/99, 
5003–04/06–08/11–13/16–17/19–21/24/27/30/32–36/44–48/52–53/59,
5061/62/64/66–69/72/75/77–78/82/84/88/90/94–95,
7016
||
|-
| 1963 || 97 ||  49   ||  123 || align=left | 4074/76/81/87/90/96/98, 
5001/15/22–23/25/29/31/38/40–41/43/49–51/58/60/65/71/80–81/87/92–93/97/99,
7000–01/06–07/09/15/17–18/20–21/27–28/30–31/33/36–37
|| [[GWR 4073 Class 5029 Nunney Castle|5029]], [[GWR 4073 Class 5043 Earl of Mount Edgcumbe|5043]], [[GWR 4073 Class 5051 Earl Bathurst|5051]], [[GWR 4073 Class 5080 Defiant|5080]] & [[GWR 4073 Class 7027 Thornbury Castle|7027]] preserved
|-
| 1964 || 48 ||  36   ||  159 || align=left | 4079–80/82/88–89/93, 
5000/02/18/26/37/39/54–57/70/73–74/76/85/89/91/96/98,
7002–05/08/10/12/19/25–26/32
|| [[GWR 4073 Class 4079 Pendennis Castle|4079]] preserved
|-
| 1965 || 12 ||  12   ||  171 || align=left | 5014/42/63, 7011/13–14/22–24/29/34–35.
|| [[GWR 4073 Class 7029 Clun Castle|7029]] preserved
|}

==List of locomotives==
See [[List of GWR 4073 Class locomotives]]
{{Clear}}

==Preservation==
On 4 March 1967, Nos. [[GWR 4073 Class 7029 Clun Castle|7029 ''Clun Castle'']] and [[GWR 4073 Class 4079 Pendennis Castle|4079 ''Pendennis Castle'']] hauled specials from [[Banbury railway station|Banbury]] and [[Oxford railway station|Oxford]] respectively to [[Chester railway station|Chester]], to mark the end of through trains between Paddington and [[Birkenhead Woodside railway station|Birkenhead]]. These two, and six other Castles, survive in preservation.
[[File:Defiant and Earl of Mount Edgcumbe at Tyseley.jpg|thumb|[[GWR 4073 Class 5080 Defiant|5080 ''Defiant'']] and [[GWR 4073 Class 5043 Earl of Mount Edgcumbe|5043 ''Earl of Mount Edgcumbe'']]  at [[Tyseley Locomotive Works|Tyseley]]]]
Of the eight Castles to be preserved, six have steamed in preservation and have been operated on the main line. Three were obtained direct from BR, 4073, 4079 and 7029, with the remaining five being rescued from [[Barry Scrapyard]].

No. 4073 ''Caerphilly Castle'' was given directly to the [[National Collection]] upon withdrawal and has not run since being preserved. It can currently be found at STEAM, the [[Museum of the Great Western Railway]] in Swindon. No. 7027 ''Thornbury Castle'' was in ex-Barry Scrapyard condition and in July 2016 was sold by [[Pete Waterman]] to the Somerset transport firm JJP Holdings SW,  transported to [[Weston-super-Mare]] on a [[Lowboy (trailer)|low loader]], then placed on a temporary track in the [[Crosville Motor Services (Weston-super-Mare)|Crosville Motor Services]] bus depot. In summer 2018 it was moved briefly to [[Tyseley Locomotive Works]] in Birmingham to make an appearance at their open weekend before moving to its planned home at the [[West Somerset Railway]] for restoration. It is now located at [[Loughborough]] on the [[Great Central Railway (heritage railway)|Great Central Railway]],<ref>{{Cite web| url=https://www.thornburycastle7027.co.uk/kinlet-history.php| url-status=dead| title=History of 7027 Thornbury Castle| website=Castle Class Steam Locomotive Thornbury Castle| publisher=Thornbury Castle 7027 Society| language=en| archive-url=https://web.archive.org/web/20180922024500/https://www.thornburycastle7027.co.uk/kinlet-history.php| archive-date=22 September 2018|year=2018<!--copyright date-->}}</ref> but will not be restored to mainline standards as its current owner intends to run it for its first ticket on the GCR before considering future mainline certification.

Two of the eight preserved Castles, nos. 5043 ''Earl of Mount Edgcumbe'' and 7029 ''Clun Castle'', are fitted with double chimneys while the remaining six are still fitted with the original single chimney.

4079 was purchased by [[Sir William McAlpine]] and hauled a small number of railtours on the main line in its early preservation years before being sold to [[Hamersley Iron]] in the [[Pilbara]] region of [[Western Australia]] and exported in 1977.<ref>Castle goes down under ''[[Railway Gazette International]]'' July 1977 page 28</ref> In 1989 it was moved by road to [[Perth]] where it double-headed with [[LNER Class A3 4472 Flying Scotsman|4472 ''Flying Scotsman'']] operating as far as [[Esperance, Western Australia|Esperance]].<ref>The World's Heaviest Driverless Trains ''[[Locomotives International]]'' issue 125 June 2020 page 24</ref> In 2000 it was donated by [[Rio Tinto (corporation)|Rio Tinto]] to the Great Western Society and restored to operational condition at the [[Didcot Railway Centre]] in 2021.<ref>Homeward Bound ''The Railway Magazine'' issue 1187 March 2000 pages 20-26</ref>

[[File:Didcot Railway Centre GWR 4073 Castle Class Display Event 4th March 2023.jpg|thumb|4 of the preserved Castle locomotives on display for the classes Centenary celebration at the Didcot Railway Centre, 4 March 2023]]
{{as of|2024}}, three Castles are operational. Both 5043 and 7029 have mainline certificates with 4079 restricted to only operate on heritage lines.<ref name=Holden /> Two engines, 5029 and 5080, are in the process of undergoing overhauls. 5080 is due to have its boiler assessed in 2024 to ascertain the cost of its overhaul; to speed up the engine's return to service only the boiler is to be overhauled while its bottom-end remains intact. The engine will only operate on heritage railways at first, but a full mechanical overhaul to mainline standards will be undertaken once enough money has been raised. The engine will eventually become part of Tyseley's pool of mainline certified alongside class members 5043 and 7029.<ref name="Update page 13">5080 Update ''Trackside'' issue 32 March 2024 page 13</ref><ref name="Trackside' page 9">5080 Update on future ''Trackside'' issue 33 April 2024 page 9</ref> In 2023, 5029 was undergoing a mainline standard overhaul to be completed by late 2024.<ref name="Crewe page 76">Progress on 5029's ongoing overhaul at Crewe ''Steam Railway'' issue 549 September 2023 page 76</ref><ref name="Steam Railway' page 76">Update on 5029's overhaul ''Steam Railway'' issue 549 September 2023 page 76</ref>

4079 was originally planned to operate on the mainline following completion of its  overhaul, but Didcot later announced that they intended to stop operating on the mainline, running only on heritage railways.<ref name=Holden>{{Cite web|last=Holden|first=Michael|date=12 December 2019|title=Steam locomotive 6023 King Edward II retired from mainline work|url=https://www.railadvent.co.uk/2019/12/steam-locomotive-6023-king-edward-ii-retired-from-mainline-work.html|website=RailAdvent|language=en-GB}}</ref> Upon completion of its restoration, 7027 is also intended to operate only on heritage railways, however debate over its restoration continued.

{| class="wikitable collapsible" style="text-align:center;"
|-
! Image
! Number
! Name (Current in Bold)
! Built
! Renamed
! Withdrawn
! Chimney fitted
! Tender fitted
! Owner
! Livery
! Home Base
! Current status
! Mainline Certified
! Notes
|-
| [[File:Caerphilly Castle Steam museum Swindon.jpg|120px]]
| [[GWR 4073 Class 4073 Caerphilly Castle|4073]]
| [[Caerphilly Castle]]
| August 1923
|–
| May 1960
| Single
| Churchward
| [[National Railway Museum]]
| GWR Lined Green, Great Western Lettering
| [[Museum of the Great Western Railway]]
| On static display
| No
|
|-
| [[File:GWR 4079 Pendennis Castle Didcot Railway Centre 4th March 2023.jpg|120px]]
| [[GWR 4073 Class 4079 Pendennis Castle|4079]]
| [[Pendennis Castle]]
| February 1924
| –
| May 1964
| Single
| Collett
| [[Great Western Society]]
| GWR Lined Green, Great Western Lettering 
| [[Didcot Railway Centre]]
| Operational, (Boiler Certificate 2021–31)
| No
|
|-
| [[File:5029 Nunney Castle Didcot old slide.jpg|120px]]
| [[GWR 4073 Class 5029 Nunney Castle|5029]]
| [[Nunney Castle]]
| May 1934
| –
| December 1963
| Single
| Collett
| [[Jeremy Hosking]]
| BR Lined Green, TBC (on completion)
| [[Crewe Diesel TMD]]
| Under Overhaul<ref name="Steam Railway' page 76"/>
| No, to be certified
| Overhaul anticipated for completion in late 2024.<ref name="Crewe page 76"/>
|-
| [[File:5043 Earl of Mount Edgcumbe parked up around the turntable.jpg|120px]]
| [[GWR 4073 Class 5043 Earl of Mount Edgcumbe|5043]]
| '''[[Earl of Mount Edgcumbe]]'''<br/>([[Barbury Castle]])
| March 1936
| September 1937
| December 1963
| Double
| Hawksworth
| [[Birmingham Railway Museum]]
| BR Lined Green, Early Emblem
| [[Tyseley Locomotive Works]]
| Operational (Boiler Certificate 2023–33).
| Yes (2023-Ongoing)
|
|-
| [[File:GWR 5051 Drysllwyn Castle Didcot 3rd March 2024.jpg|120px]]
| [[GWR 4073 Class 5051 Earl Bathurst|5051]]
| [[Earl Bathurst]]<br/>('''[[Dryslwyn Castle|Drysllwyn Castle]]''')
| May 1936
| August 1937
| May 1963
| Single
| Collett
| [[Great Western Society]]
| GWR Lined Green, Shirtbutton Logo
| [[Didcot Railway Centre]]
| On static display
| No
|
|-
| [[File:Defiant parked up around the turntable.jpg|120px]]
| [[GWR 4073 Class 5080 Defiant|5080]]
| '''[[Boulton Paul Defiant|Defiant]]'''<br/>([[Ogmore Castle]])
| May 1939
| January 1941
| April 1963
| Single
| Collett
| [[Birmingham Railway Museum]]
| GWR Lined Green, GW Lettering (on completion)
| [[Tyseley Locomotive Works]]
| Undergoing mainline standard overhaul.<ref>[http://www.vintagetrains.co.uk/defiant.aspx/ Defiant Club] {{Webarchive|url=https://web.archive.org/web/20180914091640/http://www.vintagetrains.co.uk/defiant.aspx |date=14 September 2018 }} The 5080 Defiant Club</ref>
| No, to be certified
| 5080's tender is undergoing overhaul with completion expected before the end of 2024 and 5080's boiler is due to be assessed in 2024 to ascertain the cost of an overhaul.
<ref name="Update page 13"/><ref name="Trackside' page 9"/>
|-
| [[File:7027 Thornbury Castle in 2016.JPG|120px]]
| [[GWR 4073 Class 7027 Thornbury Castle|7027]]
| [[Thornbury Castle]]
| August 1949
| –
| December 1963
| Single
| Hawksworth
| [[Didcot Railway Centre|Great Western Society's]] 4709 Group
| BR Lined Green, TBC (on completion)
| [[Great Central Railway (heritage railway)|Great Central Railway]]
| Stored
| No
| Initially undergoing restoration but now sold to the 4709 Group which intends to use the boiler in their project to re-create a [[GWR 4700 Class]].<ref>{{cite web | last=Holden | first=Michael | title=Steam locomotive 7027 Thornbury Castle set for Great Central Railway restoration | website=RailAdvent | date=23 January 2020 | url=https://www.railadvent.co.uk/2020/01/steam-locomotive-7027-thornbury-castle-set-for-great-central-railway-restoration.html }}</ref><ref>{{Cite web |title=4709 Group buys Thornbury Castle|first=Paul|last=Perton|url=https://www.4709.org.uk/4709blog/4709-group-buys-thornbury-castle |website=4709 – The Ultimate British 2–8–0 |date=23 August 2023<!--from page source-->}}</ref><ref>{{Cite web |title=4709 Group purchases Great Central Railway-based steam locomotive 7027 Thornbury Castle|first=Michael|last=Holden|url=https://www.railadvent.co.uk/2022/08/4709-group-purchases-great-central-railway-based-steam-locomotive-7027-thornbury-castle.html/ |date=11 August 2022|website=RailAdvent |language=en-GB}}</ref>

|-
| [[File:7029 Clun Castle on the turntable at Tyseley LW.jpg|120px]]
| [[GWR 4073 Class 7029 Clun Castle|7029]]
| [[Clun Castle]]
| May 1950
| –
| December 1965
| Double
| Collett
| [[Birmingham Railway Museum]]
| BR Lined Green, Late Crest
| [[Tyseley Locomotive Works]]
| Operational, boiler certificate 2017–27
| Yes (2019-Ongoing) 
|
|}

==References==
===Citations===
{{Reflist}}

===Bibliography===
{{Refbegin}}
* {{RCTS-LocosGWR-1|year=1968}}
* {{cite book |last1=Black |first1=Stuart |title=Loco Spotter's Guide |date=23 February 2017 |publisher=[[Bloomsbury Publishing]] |location=London, United Kingdom |isbn=978-1472820495 |url=https://books.google.com/books?id=u6DDDQAAQBAJ |access-date=24 November 2020}}
* {{Cite book|last=Champ|first=Jim |title=An Introduction to Great Western Locomotive Development |year=2018 |publisher=[[Pen and Sword Books|Pen & Sword Transport]] |isbn=978-1-4738-7784-9 |location=Barnsley |oclc=1029234106 |ol=26953051M }}
* {{RCTS-LocosGWR-8|edition=1st }}
* {{cite book|last=Nock|first=O. S.|title=British Locomotives of the 20th Century Vol.1. |year=1983|publisher=Book Club Associates|location=London}}
* {{cite book|last=Nock|first=O. S.|title=The GWR Stars, Castles and Kings |year=1980|publisher=Book Club Associates|location=London}}
* {{cite book |last=Vaughan |first=Adrian |title=Obstruction Danger |year=1989 |publisher=Patrick Stephens Limited |location=Wellingborough |isbn=1-85260-055-1 }}
* {{cite book|last=Haresnape|first=Brian| title=Collett & Hawksworth Locomotives—A Pictorial History| publisher=Ian Allan Ltd| year=1978| isbn=0-7110-0869-8 }}
*{{Whitehurst GW Engines from 1940|pages=36–37, 44–46, 64, 103, 143}}
{{Refend}}

*{{cite magazine |first = O.S.|last = Nock |magazine=The Engineer| title = British Locomotive Working in Wartime – The G.W.R. "Castle Class"| year = 1945| volume = 180}}, in two parts: [http://www.gracesguide.co.uk/images/e/e9/Er19450817.pdf No.I, 17 Aug., pp.122-125]; [http://www.gracesguide.co.uk/images/9/9a/Er19450824.pdf No.II, 24 Aug. 1945., pp.144-146]

==External links==
{{Commons category|GWR 4073 Class}}
* {{cite web| url=http://www.greatwestern.org.uk/m_in_cas.htm| title=4073 'Castle' class introduction| work=Great Western steam locomotives| author=Daniel, John}}
*[http://www.llantiliocastle.co.uk 5028 Llantilio Castle Home Page] The "life story" of this GWR locomotive.

{{GWR Castle Class}}
{{GWR Locomotives |state=collapsed}}
{{Authority control}}

[[Category:GWR 4073 Class| ]]
[[Category:Great Western Railway locomotives|4073]]
[[Category:4-6-0 locomotives]]
[[Category:Railway locomotives introduced in 1923]]
[[Category:Standard-gauge steam locomotives of Great Britain]]
[[Category:Articles containing video clips]]
[[Category:2′C h4 locomotives]]