British Rail Class 25

class of 327 Bo′Bo′ 1250hp diesel-electric locomotives

The British Rail Class 25 diesel locomotives were originally known as British Railways Type 2. They were nicknamed Rats. 327 locomotives of this type were built between 1961 and 1967.

British Rail Class 25
Class 25 locomotive stands on Springs Branch Traction Maintenance Depot at Wigan
Type and origin
Power typeDiesel-electric
BuilderBritish RailwaysCrewe Works, Darlington Works and Derby Works; Beyer, Peacock & Co.
Build date1961–1967
Total produced327
Specifications
Configuration:
 • WhyteBo-Bo
 • UICBo'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 (11.125 m)
Length50 ft 6 in (15.392 m)
Width9 ft 1 in (2.769 m)
Height12 ft 8 in (3.861 m)
Loco weight71 long tons (72.1 t) to 76 long tons (77.2 t)
Fuel capacity500 imp gal (2,300 L; 600 US gal)
Prime moverSulzer 6LDA28-B
TransmissionDC generator, DC traction motors
MU working Blue Star
Train heatingSteam generator
Train brakesVacuum
Performance figures
Top speed90 mph (145 km/h)
Power outputEngine: 1,250 hp (932 kW)
Tractive effortMaximum: 39,000 lbf (173,000 N) to 45,000 lbf (200,000 N)
Brakeforce38 long tons-force (380 kN)
Career
Railroad(s)British Railways
NumberD5151–D5299, D7500–D7677; later 25001–25327
NicknamesRats
Axle load classRoute availability 4