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 called 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.

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.

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 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 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.info from wikipedia