British Rail Class 24

class of 151 Bo′Bo′ 1160hp diesel-electric locomotives

The British Rail Class 24 diesel locomotives, originally known as the British Railways Type 2, were built from 1958 to 1961. One hundred and fifty-one of these locomotives were built at Derby, Crewe and Darlington. The first twenty locomotives were part of the 1955 British Rail modernisation plan. This class was used as the basis for the more powerful Class 25 locomotives.

British Railways Type 2
British Rail Class 24
Class 24, no. 24065 at Motherwell depot, May 1976
Type and origin
Power typeDiesel-electric
BuilderBritish RailwaysDerby Works, Darlington Works and Crewe Works
Build date1958–1961
Total produced151
Specifications
Configuration:
 • UICBo'Bo'
 • CommonwealthBo-Bo
Gauge4 ft 8 12 in (1,435 mm) standard gauge
Wheel diameter3 ft 9 in (1.143 m)
Minimum curve4.5 chains (91 m)
Wheelbase36 ft 6 in (11.13 m)
Length50 ft 6 in (15.39 m)
Width8 ft 10 in (2.69 m)
Height12 ft 8 in (3.86 m)
Loco weightClass 24/0: 79 long tons (80.3 t; 88.5 short tons)
Class 24/1: 73 long tons (74.2 t; 81.8 short tons)
Fuel capacityClass 24/0: 546 imp gal (2,480 L; 656 US gal)
Class 24/1: 500 imp gal (2,300 L; 600 US gal)
Prime moverSulzer 6LDA28
GeneratorBTH RTB15656 DC
Traction motorsBTH 137BY, DC, 4 off
TransmissionDiesel electric
MU working Blue Star
Train heatingSteam generator
Train brakesVacuum
Performance figures
Maximum speed75 mph (121 km/h)
Power outputEngine: 1,160 hp (865 kW)
At rail: 843 hp (629 kW)
Tractive effortMaximum: 42,000 lbf (186.8 kN)
Continuous: 21,300 lbf (94.7 kN)
Brakeforce38 long tons-force (380 kN)
Career
OperatorsBritish Railways
NumbersD5000–D5150; later 24001–24047, 24051–24141
Axle load classClass 24/0: RA 7 (6 from 1969)
Class 24/1: RA 6 (5 from 1959)
Retired1967–1980
PreservedFour (list)

The final survivor, no. 24081, was withdrawn from Crewe depot in 1980.