GWR class 4900

GWR class 4900
5976 Ashwicke Hall in Exeter St David's MPD 1953
Numbering:	4900 (prototype), 4901 - 4999, 5900 - 5999, 6900 - 6958
Number:	258 + 1 prototype
Manufacturer:	Swindon Railway Works
Year of construction (s):	1924 (prototype), 1928–1943
Retirement:	1959-1965
Axis formula :	2'C
Type :	2'Ch2
Gauge :	1435 mm ( standard gauge )
Length over buffers:	19.21 m
Height:	4.045 m
Width:	2,724 m
Smallest bef. Radius:	141 m (when driving slowly), 161 m (general)
Service mass:	76.2 t
Wheel set mass :	19.3 t
Starting tractive effort:	121 kN
Coupling wheel diameter:	1829 mm
Driving wheel diameter:	1829 mm
Impeller diameter front:	914 mm
Number of cylinders:	2
Cylinder diameter:	470 mm
Piston stroke:	724 mm
Boiler overpressure:	1.55 kPa
Radiant heating surface:	14.4 m²
Tubular heating surface:	156.7 m²
Superheater area :	24.4 m²
Water supply:	16 m³ - 18 m³
Fuel supply:	Hard coal
Train heating:	steam
Coupling type:	Screw coupling

The Class 4900 or Hall class of the Great Western Railway was a series of tender locomotives with a 2'C wheel arrangement with a two-cylinder superheated steam engine based on a design by Charles Collett . 259 locomotives with the road numbers 4900-4999, 5900-5999 and 6900-6958 were built. They were suitable for both passenger and freight train service and formed the model for class 5 of the LMS and class B1 of the LNER .

history

In 1923 the GWR was well equipped with locomotives for fast passenger train service like the Saints and the Stars , and the Castles began their service. The 1'C locomotives of the GWR class 4300 built for passenger and freight train services , however, were no longer able to cope with the increasing train loads. George Jackson Churchward had therefore designed the 1'D-coupled GWR Class 4700 with drive wheels of 5 feet 3 inches (1727 mm) in diameter for fast freight trains and reinforcement passenger trains. Although a successful construction, they were only suitable for a few routes because of their size. Churchward's successor, Collett, therefore found a Saints- derived locomotive with smaller wheels and a leading bogie to be more suitable and therefore had track number 2925 Saint Martin converted to a 6ft 3 inch (1829 mm) drive wheel diameter in 1924 . The cylinder position was adapted to the new chassis and a driver's cab of the castles was installed. During the trials, which lasted until 1927, further changes were made to the boiler and steam lines.

After the successful attempts, a series of 80 locomotives were ordered in Swindon in 1928 , which were delivered by 1930 with the numbers 4901 to 4980. The prototype was given the new number 4900. The first 14 locomotives were tested on the demanding Cornish Main Line and proved themselves so well that 20 more copies were ordered when the first series was completed (track numbers 4981-99 and 5900). Further orders followed in the 1930s and early 1940s, until 1943, when the 259th Oxburgh Hall locomotive with track number 6958 was delivered. Except for the prototype, all were named after English and Welsh mansions ( Halls ). 71 more locomotives were delivered under Collett's successor Frederick Hawksworth as Modified Halls with numerous improvements adapted to technical progress.

technical features

The series machines differed little from the prototype. The impeller diameter has been reduced from 3 feet 2 inches (965 mm) to 3 feet (914 mm) and the valve stroke increased to 7.5 in (191 mm) compared to the Saints . The mass of the locomotive increased by 2 long tons 10 cwt (2.5 t) to 75 long tons 0 cwt (76.2 t), and the pulling force of 27.275 lbf (121.33 kN) exceeded the Saints' 24.935 lbf (110.92 kN) . Originally the locomotives were equipped with Churchward tenders with a water capacity of 3,500 imp gal (16,000 l), from track number 4958 they received Collett's larger tenders with 4,000 imp gal (18,000 l) water capacity. Some locomotives delivered later also received smaller tenders, if they were available when they were put into service.

The high axle load of the locomotives prevented them from being used on branch lines. Nevertheless - as the high number of units showed - they were operationally successful and are occasionally regarded as the first true multi-purpose locomotives and thus the forerunners of the LMS class 5, the LNER class B1 and the BR Standard Class 5. However, successful multi-purpose locomotives with the 1'C and 2'C axles had already been built for the GWR and other British railways, including the GWR class 4300, which was to be replaced by the class 4900.

Retirement and conservation

Except for track number 4911 Bowden Hall , which was scrapped in 1941 after a bomb damage, all Halls were taken over by British Railways in 1948. Official retirement began in 1959 when the prototype Saint Martin was withdrawn from circulation. By then it had covered a total of 2,092,500 miles (before and after the conversion). By 1965 the entire class had been retired. Eleven locomotives have survived, all of which had been parked at Woodham Brothers' metal recycling plant in Barry . Seven of them were in the museum. Track number 4942 Maindy Hall was converted into a Saint locomotive and put into service in April 2019 as Lady of Legend with the number 2999. Track number 4965 Rood Ashton Hall is approved for route service and can therefore carry special trains. Lane number 5972 Olton Hall was used in the Harry Potter films . Other locomotives are currently being refurbished.

Preserved machines

number	Surname	image	Built	Retired	Owner	Location	status	Approval for route service	Remarks
4920	Dumbleton Hall		March 1929	December 1965		South Devon Railway	Switched off	No
4930	Hagley Hall		May 1929	December 1963	Severn Valley Railway	Severn Valley Railway	Is being overtaken	No
4936	Kinlet Hall		June 1929	January 1964	Kinlet Hall Loco. Co.	Tyseley Locomotive Works	Is being overtaken	No, provided
4942	Maindy Hall		July 1929	December 1963	Didcot Railway Center	Didcot Railway Center	Conversion to GWR class 2900 Lady of Legend	No, provided	Conversion to Saint class
4953	Pitchford Hall		August 1929	May 1963	Epping Ongar Railway	Epping Ongar Railway	Is being overtaken	No
4965	Rood Ashton Hall		November 1930	March 1962	Tyseley Locomotive Works	Tyseley Locomotive Works	Operational	Yes (2009-2019)
4979	Wootton Hall		February 1930	December 1963	Furness Railway Trust	Ribble Steam Railway	Is being restored	No
5900	Hinderton Hall		March 1931	December 1963	Didcot Railway Center	Didcot Railway Center	Fixed museum locomotive	No	Pulled nine former GWR passenger cars on a route from Didcot in the 1970s.
5952	Cogan Hall		December 1935	June 1964	Betton Grange Society	Llangollen Railway	Switched off	No	Tender and some parts used for GWR class 6800 Betton Grange . Should be restored after completion of No. 6880.
5967	Bickmarsh Hall		March 1937	June 1964		Northampton & Lamport Railway	Will be worked up	No
5972	Olton Hall		April 1937	December 1963	David Smith	Warner Brothers Studio Tours	Fixed museum locomotive	No, provided	Was used under the name Hogwarts Castle with red paint in the Harry Potter films.

Individual evidence

1. ^ Le Fleming, HM (November 1960) [1953]. White, DE, ed. The Locomotives of the Great Western Railway, part eight: Modern Passenger Classes (2nd ed.). Kenilworth: RCTS. S. H29.
2. ^ Le Fleming & White 1960, p. H29
3. ^ Le Fleming & White 1960, p. H30
4. ^ Herring, Peter (2004). Classic British Steam Locomotives. Wigston: Abbeydale Press. P. 118. ISBN 1-86147-138-6
5. ^ Casserley, HC (1960). The Historic Locomotive Pocket Book. London: Batsford. Pp. 217, 222.
6. ^ Casserley, HC (1961). Locomotives of British Railways. London: Spring Books. P. 28.
7. ^ Riley, RC (1966). Great Western Album. Shepperton: Ian Allan. P. 90. ISBN 0-7110-0073-5
8. ↑ ^{a b} The Saint Project . Retrieved April 10, 2019.
9. ^ Nigel Devereux: April launch date for Didcot's Saint No. 2999 . In: Railway Magazine . February 18, 2019.
10. ↑ https://www.flickr.com/photos/13296226@N02/4541734360
11. ↑ The name of the locomotive in the film is considered a joke in museum railroad circles, since the locomotives of the much larger GWR class 4073 are referred to as castles .