The GWR 1400 Class is a class of steam locomotive designed by the Great Western Railway for branch line passenger work. It was originally classified as the 4800 Class when introduced in 1932, and renumbered in 1946.
 Although credited to Charles Collett, the design dated back to 1868 with the introduction of the George Armstrong 517 class.
 Like the 48xx/14xx, the 517 Class was a lightweight loco for branchline work; it was built at Wolverhampton Works between 1868 and 1885.
 In this period evolutionary changes included:
 Later gradual changes included: Belpaire fireboxes, boilers rated at 165 psi (1.14 MPa) as opposed to 150 psi (1.0 MPa), full cabs, extended bunkers and the progressive conversion of short wheelbase locos to 15 ft 0 in (4.57 m) or 15 ft 6 in (4.72 m). From 1924 onwards, several were converted to run with an autocoach, and in this configuration were the direct ancestors of the 48xx class.
 In this form, the updated 517s were but a small step away from the 48xx. The wheelbase was still 15 ft 6 in (4.72 m), the boiler still rated at only 165 psi (1.14 MPa), and the wheels 5 ft 2 in (1,575 mm) and 3 ft 8 in (1,118 mm). New was the Collett-style cab and bunker and the boiler nominally to a new design. A three bar crosshead was added to the motion. This was a 1924 innovation introduced with the GWR 5600 Class and also seen in the 1930s-built 5400, 6400 and 7400 classes of pannier tanks.
 The 4800 Class was designed as a more modern version of the 517 Class, which were by then beginning to show their relative age. The first locomotive, No 4800, was built by Swindon Works and entered service in 1932, with a further seventy-four engines of this type following up to 1936. During this period, Swindon also built twenty 5800 Class engines, which were broadly similar but which were not fitted with autotrain equipment or the Swindon top feed as later fitted to a number of 4800 class engines.
 The 4800 Class locomotives retained their original numbers until the GWR decided to experimentally convert twelve 2800 Class 2-8-0s for oil-firing. It was decided that the converted engines would be reclassified as the 4800 Class and so the 75 tank locomotives already carrying this designation were reclassified as the 1400 Class with running numbers 1400-1474. The engines did not revert to their original classification after the experiment ended in 1948. They could reach a maximum speed of 80 mph (130 km/h) which was much faster than the diesel railcars designed to replace them could reach.
 The 1400 Class was designed to work with the GWR design of autocoach, a specialist coach designed for push-pull working and which could also be used with engines of other classes such as the 517s, the GWR 5400 Class, the GWR 6400 Class and the older GWR 2021 Class. This lack of auto gear was the cause of earlier scrapping of the 5800 Class as there was no work for them. The last, no. 5815, was withdrawn from Swindon shed in April 1961.
 The auto-fitted locos fared little better; scrapping commenced in 1956 and all were withdrawn by early 1965. Nos. 1442 and 1450 were withdrawn from Exmouth Junction shed in May 1965. By the early 1960s several had been in store (parked in an out-of-the-way siding with a tarpaulin over the chimney) for some time, being occasionally steamed to replace failed diesels.
 Four examples have been preserved, all late withdrawals from service in the 1963-1965 period. All went direct to preservation from British Railways in relatively good condition.
 Loco numbers in bold mean their current number.
 1442 spent its last years working between Tiverton and Tiverton Junction and became known as Tivvy Bumper. It was purchased by Lord Amory in 1965 for display at Tiverton.
All preserved examples apart from 1442 are fitted with auto train equipment, and 1450 has also operated on the mainline in preservation, but due to its size was restricted in the amount of work it could do and was also restricted on mileage, as the 1400s only have a max water capacity of 800 imp gal (3,600 L; 960 US gal). During the 1990s it worked a number of Dawlish Donkey trips from Exeter St Davids to Newton Abbot.