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GWR 4700 Class

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GWR 4700 Class
4705 at the Southall Locomotive Depot, in 1962
Type and origin
Power typeSteam
DesignerGeorge Jackson Churchward
BuilderGWR Swindon Works
Order numberLots 214, 221
Serial number4700: 2866,
4701–4708: none
Build date1919 (1), 1922–1923 (8)
Total produced9
Specifications
Configuration:
 • Whyte2-8-0
 • UIC1'D h2
Gauge4 ft 8+12 in (1,435 mm) standard gauge
Leading dia.3 ft 2 in (0.965 m)
Driver dia.5 ft 8 in (1.727 m)
Minimum curve8 chains (530 ft; 160 m) normal,
7 chains (460 ft; 140 m) slow
Length66 ft 4+14 in (20.22 m)
Width8 ft 11 in (2.718 m)
Height13 ft 4+34 in (4.083 m)
Axle load19 long tons 12 cwt (43,900 lb or 19.9 t)
19 long tons 12 hundredweight (19.9 t; 22.0 short tons) full
Adhesive weight73 long tons 8 cwt (164,400 lb or 74.6 t)
73 long tons 8 hundredweight (74.6 t; 82.2 short tons) full
Loco weight82 long tons 0 cwt (183,700 lb or 83.3 t)
82 long tons 0 hundredweight (83.3 t; 91.8 short tons) full
Tender weight46 long tons 14 cwt (104,600 lb or 47.4 t)
45 long tons 14 hundredweight (46.4 t; 51.2 short tons) full
Fuel typeCoal
Water cap.3,500 or 4,000 imperial gallons (16,000 or 18,000 L; 4,200 or 4,800 US gal)
Firebox:
 • Grate area30.28 sq ft (2.813 m2)
BoilerGWR Standard No. 7[1]
Boiler pressure225 lbf/in2 (1.55 MPa)
Heating surface:
 • Firebox169.75 sq ft (15.770 m2)
 • Tubes2,062.35 sq ft (191.599 m2)
Superheater:
 • Type4-element or 6-element
 • Heating area4-element: 211.20 sq ft (19.621 m2),
6-element: 276.98 sq ft (25.732 m2)
CylindersTwo, outside
Cylinder size19 in × 30 in (483 mm × 762 mm)
Valve gearStephenson
Valve typePiston valves
Performance figures
Tractive effort30,460 lbf (135.5 kN)
Career
OperatorsGWR » BR
Class4700
Power classGWR: D,
BR: 7F
Numbers4700–4708
NicknamesNight Owls
Axle load classGWR: Red
Withdrawn1962–1964
DispositionAll original locomotives scrapped; one new-build under construction

The Great Western Railway (GWR) 4700 Class was a class of nine 2-8-0 steam locomotives, designed by George Jackson Churchward. They were introduced in 1919 for heavy mixed-traffic work. Although primarily designed for fast freight, the class also sometimes hauled passenger trains, notably heavy holiday expresses in the summer months. They were unofficially nicknamed "Night Owls" because they were primarily designed to haul goods during the night and they could be seen simmering in the daylight, awaiting their nocturnal duties.[2][3][4]

Background

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At the end of the First World War, the running department of the GWR identified the need for a larger version of the successful GWR 4300 Class 2-6-0 incorporating the Swindon No. 1 boiler. They envisaged a smaller version of the successful Saint class 4-6-0 with 5 ft 8 in (1.727 m) driving wheels - the intermediate of Churchward's three standard wheel sizes, for express goods trains. However, Churchward preferred a 2-8-0 design for this purpose.[5]

Prototype

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The prototype of the new class was built at Swindon Works in May 1919 (Lot 214) and was the last design by Churchward. It was numbered 4700. According to the RCTS monograph, the design was not successful as built because the No. 1 boiler proved to be inadequate for such a large engine.[6] In May 1921, it was therefore rebuilt with a newly designed and larger Swindon No. 7 boiler. However, according to Cook it was built with a Standard No. 1 boiler as the intended design of the larger Standard No. 7 boiler, which was not yet ready.[7][page needed]

Production series

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Eight further locomotives with the larger No. 7 boilers and detail differences were ordered by Churchward in 1921 (Lot 221), but these only appeared after his retirement. These were numbered 4701 to 4708. Although they were mechanically successful locomotives, their large size severely restricted their route availability and so no more examples were built. Churchward's successor Charles Collett later rebuilt a Saint Class with 6 ft 0 in (1.829 m) wheels to form the Hall Class which was a far more versatile mixed traffic locomotive.[8] Later, Collett would produce the Grange Class which was exactly as the traffic department had originally envisaged: a 4-6-0 with Standard No. 1 boiler and 5 ft 8 in driving wheels. The class was originally fitted with 3,500 imperial gallons (16,000 L; 4,200 US gal) tenders but during 1933/4 these were replaced by 4,000 imperial gallons (18,000 L; 4,800 US gal) tenders.

Use

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The class were primarily used on fast overnight freight services on the London, Exeter and Plymouth, London-Bristol and London, Birmingham and Wolverhampton routes. In later years they were often used on heavy relief passenger services to the West of England during the summer months.

Accidents and incidents

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  • On 12 November 1958, locomotive No. 4707 was hauling a freight train when it overran signals and was derailed at Highworth Junction, Swindon, Wiltshire. A newspaper train, hauled by GWR 4073 Class 4-6-0 No. 5009 Shrewsbury Castle, collided with the wreckage.[9]
No. 4707 at Swindon Works 25 April 1954

Withdrawal

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Withdrawal of the class began in June 1962 with No. 4702, while the last were removed from service in May 1964. As a result of their limited usefulness, the mileages achieved by the class were not exceptional, with No. 4705 recording the greatest at 1,656,564 miles (2,665,981 km).

Preservation

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No members of the class were preserved. However, the Great Western Society 4709 Group made the decision to create the next locomotive in the sequence, GWR 4709. Supported via a GWS sub-group; the plan was to build it using a mixture of new parts and others recycled from former Barry scrapyard locomotives:

The plates for the new frames were cut and machined in 2012.

In order to fit within the more restrictive modern loading gauge, so that it could operate on the main line, the project has changed the plan to use the 2800 cylinder, and has instead had new cylinders designed and cast.[14]

See also

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References

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  1. ^ Champ, Jim (2018). An Introduction to Great Western Locomotive Development. Barnsley: Pen & Sword Transport. p. 320. ISBN 978-1-4738-7784-9. OCLC 1029234106. OL 26953051M.
  2. ^ Daniel, John. "4700 class introduction". The Great Western Archive. Retrieved 18 September 2020.
  3. ^ "4700 2-8-0 GWR Churchward 4700 – 4708". Preserved British Steam Locomotives. 16 June 2017. Retrieved 18 September 2020.
  4. ^ Perton, Paul. "47XX History". 4709 – THE ULTIMATE BRITISH 2–8–0. Squarespace. Retrieved 18 September 2020.
  5. ^ le Fleming, H.M. (November 1960) [1953]. White, D.E. (ed.). The Locomotives of the Great Western Railway, part eight: Modern Passenger Classes (2nd ed.). Kenilworth: RCTS. pp. H29.
  6. ^ Le Fleming, H.M. (1962). The Locomotives of the Great Western Railway, part nine: Standard two-cylinder Classes. Kenilworth: RCTS. pp. J24-5. ISBN 0901115371.
  7. ^ Cook, K.J. (1974). Swindon Steam. Ian Allan.
  8. ^ Le Fleming 1962, p. J25
  9. ^ Trevena, Arthur (1980). Trains in Trouble. Vol. 1. Redruth: Atlantic Books. p. 47. ISBN 0-906899-01-X.
  10. ^ "5199 Project". The 5199 Project. 2011. Archived from the original on 5 March 2012. Retrieved 25 July 2011.
  11. ^ "4709 Group buys Thornbury Castle — 4709 – The Ultimate British 2–8–0". 4709 – The Ultimate British 2–8–0. 13 August 2022. Retrieved 13 August 2022.
  12. ^ "4709 Group purchases Great Central Railway-based steam locomotive 7027 Thornbury Castle". RailAdvent. 11 August 2022. Retrieved 13 August 2022.
  13. ^ "7027 THORNBURY CASTLE | Didcot Railway Centre". didcotrailwaycentre.org.uk. Retrieved 13 August 2022.
  14. ^ "4709's First Cylinder cast satisfactorily at Boro Foundry". 4709 – The Ultimate British 2–8–0. 2021. Retrieved 23 September 2021.
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