British Rail Class 21

class of 58 Bo′Bo′ 1000/1100hp diesel-electric locomotives

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.

North British Type 2 diesel-electric
British Railways Class 21
D6103 at Harringay West in 1959
Type and origin
Power typeDiesel-electric
BuilderNorth British Locomotive Company
Build date1958–1960
Total produced58
 • WhyteBo-Bo
 • UICBo'Bo'
Gauge4 ft 8 12 in (1,435 mm) standard gauge
Wheel diameter3 ft 7 in (1.092 m)
Minimum curve3.5 chains (70 m)
Wheelbase37 ft 0 in (11.28 m)
Length51 ft 6 in (15.70 m)
Width8 ft 8 in (2.64 m)
Height12 ft 8 in (3.86 m)
Loco weight72.50 long tons (73.7 t)
Fuel capacity460 imp gal (2,100 L; 550 US gal)
Prime moverMAN L12V18/21S
Traction motorsGEC WT440, 4 off
TransmissionDC generator, DC traction motors
MU workingD6100–D6137: Red circle
D6138–D6157: Blue star
Train heatingSpanner 1,500 pounds (680 kg) per hour Steam generator
Train brakesVacuum
Performance figures
Top speed75 mph (121 km/h)
Power outputEngine: 1,000 hp (746 kW) or 1,100 hp (820 kW)
Tractive effortMaximum: 45,000 lbf (200.2 kN)
Brakeforce50 long tons-force (500 kN)
Railroad(s)British Railways
Axle load classRoute availability 6 (5 from 1969)
Disposition20 rebuilt to class 29, remainder scrapped
This is article is about diesel locomotives built 1958-1960. For 2007-era locomotives, see Vossloh G1206.

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