British Rail Class 21

North British Type 2 diesel-electric British Railways Class 21
D6103 at Harringay West in 1959
Type and origin Power type Diesel-electric Builder North British Locomotive Company Build date 1958–1960 Total produced 58
Specifications Configuration: ​  • Whyte Bo-Bo  • UIC Bo'Bo' Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Wheel diameter 3 ft 7 in (1.092 m) Minimum curve 3.5 chains (70 m) Wheelbase 37 ft 0 in (11.28 m) Length 51 ft 6 in (15.70 m) Width 8 ft 8 in (2.64 m) Height 12 ft 8 in (3.86 m) Loco weight 72.50 long tons (73.7 t) Fuel capacity 460 imp gal (2,100 L; 550 US gal) Prime mover MAN L12V18/21S Traction motors GEC WT440, 4 off Transmission DC generator, DC traction motors MU working D6100–D6137: ● Red circle D6138–D6157: ★ Blue star Train heating Spanner 1,500 pounds (680 kg) per hour Steam generator Train brakes Vacuum
Performance figures Top speed 75 mph (121 km/h) Power output Engine: 1,000 hp (746 kW) or 1,100 hp (820 kW) Tractive effort Maximum: 45,000 lbf (200.2 kN) Brakeforce 50 long tons-force (500 kN)
Career Railroad(s) British Railways Number D6100–D6157 Axle load class Route availability 6 (5 from 1969) Retired 1967–1968 Disposition 20 rebuilt to class 29, remainder scrapped

This is article is about diesel locomotives built 1958-1960. For 2007-era locomotives, see Vossloh G1206.

The British Rail Class 21, originally known as the North British Type 2 diesel-electric, was a type of diesel locomotive built by the North British Locomotive Company in Glasgow for British Railways in 1958-1960.

Starting in 2007, the classification has been reused for new Vossloh G1206 acquired by Euro Cargo Rail/EWS.