BR Class 03
TOPS numbers	03 004 - 03 399
Early numbers	D2000-D2199; D2370-D2390; originally 11187-11209
Builder	British Rail Swindon & Doncaster
Introduced	1957-62
Wheel Arrangement	0-6-0 (C)
Weight	30 t 4 cwt	30.6 tonnes
Height	11 ft 10 in	3.6 m
Width	8 ft 6 in	2.6 m
Length	26 ft 0 in	7.9 m
Wheel Dia.	3 ft 7 in	1.1 m
Wheelbase	9 ft 0 in	2.8 m
Minimum radius	2 chains	40 m
Maximum speed	28.5 mph	46 km/h
Engine output	204 hp	152 kW
Max. Tractive Effort	15,300 lbf	68 kN
Power at Rail	152 hp	113 kW
Brake type	Vacuum; later some Dual
Brake force	13 ton force	130 kN
Route availability	1
Fuel Tank	300 imperial gal	1400 litres
Heating type	None

The British Rail Class 03 locomotive is, together with Class 04, one of BR's most successful smaller 0-6-0 diesel-mechanical shunters. The class, numbering 230 examples, was built by British Railways' Swindon and Doncaster works in 1957-1962 and numbered D2000-D2399 (later 03004 to 03399). D2370 and D2371 were used as departmental locomotives and numbered 91 and 92 respectively.

Like other shunters of this type, they were built for lighter duties where a larger locomotive was not needed, especially at locomotive and carriage depots and as station pilots. The reduction over time in the demand for shunting locomotives meant that they were progressively withdrawn from 1968 on, many being sold to private industry, although some stayed on for much longer, including locomotives at Reading Signal Works and on the Isle of Wight, the latter remaining in service until 1993. In 1998, though, 03 179 was reinstated into service by the West Anglia Great Northern Railway Company (WAGN) for service at their Hornsey depot. The locomotive is named Clive.

A fairly large number of the class survive in preservation.

The engine is a Gardner 8-cylinder, 4-stroke 8L3 of 204 hp 152 kW connected to a Wilson-Drewry CA5 R7, 5-speed epicyclic with RF11 spiral bevel reverse and final-drive unit. Drive is through a jackshaft mounted beneath the cab, driving the wheels through coupling rods (US: side rods ).