GWR 4700 Class

GWR 4700 Class

GWR Class 4700 2-8-0 4706 at Old Oak Common MPD, London, on 15 December 1963

Type and origin Power type Steam Designer George Jackson Churchward Builder GWR Swindon Works Order number Lots 214, 221 Serial number 4700: 2866, 4701–4708: none Build date 1919 (1), 1922–1923 (8) Total produced 9

Specifications Configuration: ​  • Whyte 2-8-0  • UIC 1'D h2 Gauge 4 ft 8 1⁄2 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 curve 8 chains (530 ft; 160 m) normal, 7 chains (460 ft; 140 m) slow Length 66 ft 4 1⁄4 in (20.22 m) Width 8 ft 11 in (2.718 m) Height 13 ft 4 3⁄4 in (4.083 m) Axle load 19 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 weight 73 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 weight 82 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 weight 46 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 type Coal Water cap 3,500 or 4,000 imperial gallons (16,000 or 18,000 l; 4,200 or 4,800 US gal) Firebox:  • Firegrate area 30.28 sq ft (2.813 m2) Boiler pressure 225 lbf/in2 (1.55 MPa) Heating surface:  • Tubes 2,062.35 sq ft (191.599 m2)  • Firebox 169.75 sq ft (15.770 m2) Superheater: ​  • Type 4-element or 6-element  • Heating area 4-element: 211.20 sq ft (19.621 m2), 6-element: 276.98 sq ft (25.732 m2) Cylinders Two, outside Cylinder size 19 in × 30 in (483 mm × 762 mm) Valve gear Stephenson Valve type Piston valves

Performance figures Tractive effort 30,460 lbf (135.5 kN)

Career Operators GWR » BR Class 4700 Power class GWR: D, BR: 7F Numbers 4700–4708 Axle load class GWR: Red Withdrawn 1962–1964 Disposition All original locomotives scrapped; one new-build under construction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.

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

The prototype of the new class was built at Swindon railway 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. 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 a larger boiler, the Standard No. 7, was not yet ready.

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. Later, Collett would produce the 6800 Grange Class which was exactly as the traffic department had originally envisaged: a 4-6-0 with Std. No.1 boiler and 5'8" driving wheels. The class were 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.