Although credited to Charles Collett, the design dated back to 1868 with the introduction of the George Armstrong 517 class.

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).

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.

1401 and 1456 (doubling as 1401) were specially assigned to the film shoot, which took place primarily in the Limpley Stoke area.

[5] 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.

[10] 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.