GWR 6800 Class

Great Western Railway 6800 Class

6833 Calcot Grange at Bristol Temple Meads in British Railways green livery
Type and origin
Power type Steam
Builder Great Western Railway
Build date 1936–1939
Total produced 80
Specifications
Configuration 4-6-0
UIC class 2'C h
Gauge 4 ft 8 1⁄2 in (1,435 mm)
Leading dia 3 ft 0 in (0.914 m)
Driver diameter 5 ft 8 in (1.727 m)
Minimum curve 8 chains (530 ft; 160 m) normal,
7 chains (460 ft; 140 m) slow
Length 63 ft 0 1⁄4 in (19.21 m)
Width 8 ft 11 1⁄4 in (2.72 m)
Height 13 ft 0 in (3.96 m)
Axle load 18 long tons 8 cwt (41,200 lb or 18.7 t)
Adhesive weight 55 long tons 2 cwt (123,400 lb or 56 t)
Loco weight 74 long tons 0 cwt (165,800 lb or 75.2 t) full
Tender weight 40 long tons 0 cwt (89,600 lb or 40.6 t) full
Fuel type Coal
Fuel capacity 7 long tons 0 cwt (15,700 lb or 7.1 t)
Water cap 3,500 imp gal (16,000 l; 4,200 US gal)
Firebox:
 • Firegrate area		 27.07 sq ft (2.515 m2)
Boiler pressure 225 psi (1.55 MPa)
Heating surface:
 • Tubes and flues		 1,686.60 sq ft (156.690 m2)
 • Firebox 154.78 sq ft (14.380 m2)
Superheater:
 • Heating area		 4-element: 191.8 sq ft (17.82 m2),
6-element: 253.38 sq ft (23.540 m2)
Cylinders Two, outside
Cylinder size 18.5 in × 30 in (470 mm × 762 mm)
Performance figures
Tractive effort 28,875 lbf (128.44 kN)
Career
Operators Great Western Railway,
British Railways
Power class GWR: D; BR: 5MT
Numbers 6800–6879
Axle load class GWR: Red
First run 1936
Retired 1960–1965
Disposition All original locomotives scrapped, GWR 6880 Betton Grange being built

The Great Western Railway (GWR) 6800 Class or Grange Class was a mixed traffic class of 4-6-0 steam locomotive, built to replace the GWR 4300 Class 2-6-0. There were 80 in the class, all built at the Swindon works, using some reconditioned parts from withdrawn 4300 Class locomotives .

Background

The GWR locomotive standardisation policy pursued by G.J. Churchward envisaged a range of locomotive classes which would be suitable for the majority of duties, and yet which would share a small number of standard components.[1] Amongst the designs suggested in 1901 was a 4-6-0 with 5-foot-8-inch (1.727 m) diameter driving wheels, and the Standard No. 1 boiler.[2] Although planned in 1901, none were built during Churchward’s lifetime. C.B. Collett, (Churchward’s successor at Swindon Works) rather introduced the Hall class with 6-foot (1.829 m) diameter driving wheels.

The 4300 Class of 2-6-0 tender locomotives had been introduced on the GWR for mixed traffic duties in 1911, and by 1932 there were 342 in service.[3] However, by the mid 1930s some of the earlier examples were in need of attention and the class as a whole was struggling with some of the duties expected of them. Collettt therefore revived the Churchward proposal, but modified the design to include a cab and controls to the current style.[4] Between 1936 and 1939, one hundred 4300 Class were taken out of service and replaced by new 4-6-0 locomotives, eighty of which were of the 6800 (or Grange) class, whilst the remaining 20 were of the 7800 (or Manor) class.[5] It had been intended to replace all of the 4300 Class in this way, but the Second World War stopped the programme.[5][6]

Design and Production

The Granges were effectively a smaller-wheeled version of the GWR Hall Class.[6]

The wheels, valve motion and tenders were taken from the withdrawn engines, reconditioned and then used in the construction of the 100 new locomotives;[4][6][7] the components from one old locomotive were spread amongst more than one of the new engines.[8] The cylinders of the Granges were of the same size as those used on the 4300 Class, but the old cylinders could not be re-used because the cylinders and valves shared a common casting, and the new design called for the separation between cylinder and valve centre lines to be increased by 2 1⁄2 inches (64 mm). This was done in order to make the cylinders level with the axles, but still allow the use of the old valve motion parts.[9][10]

The locomotives were built in two batches to a single order (Lot No. 308): Nos. 6800-6859 were built between August 1936 and December 1937, and Nos. 6860-6879 appeared between February and May 1939. They were all named after Granges in the area covered by the GWR. Further construction of the class was cancelled due to the outbreak of war.[11] They were originally fitted with Churchward 3,500 imp gal (16,000 l; 4,200 US gal) tenders taken from withdrawn members of the 4300 Class. However, after the second world war several were fitted with newer 3,500 imp gal (16,000 l; 4,200 US gal) and 4,000 imp gal (18,000 l; 4,800 US gal) types.[12]

Performance

Although built to a thirty five-year old design, in service they proved to be reliable performers.[4][13] With their power and mixed traffic characteristics they could handle most duties on the network.[4] Their smaller driving wheels giving them a higher tractive effort than the Hall Class. They were often used for the haulage of perishable goods, such as fruit and broccoli, and for excursion trains.[14] However their axle loading prevented their use on some cross-country routes previously operated by the 4300 class. As a result, a lighter version in the form of the Manor Class was introduced for these duties.[7]

No. 6827 'Llanfrechfa Grange' at Swindon Works 29 November 1964.

The BR power classification of the Grange class was 5MT, its GWR power class was D and its route availability colour code was red.[15]

Withdrawal and Preservation

The entire class was withdrawn from service between 1960 and 1965 and no examples were preserved. However, GWR 6880 Betton Grange, the next Grange that was due to be built originally, is currently being built at Llangollen Railway.[16]

List of Locomotives

References

External links

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