British Rail Class 25

British Rail Class 25
Class 25/3 in BR blue at Manchester Victoria in 1980.
Type and origin
Power typeDiesel-electric
BuilderBritish Railways' Crewe Works, Darlington Works and Derby Works; Beyer, Peacock & Co.
Build date1961–1967
Total produced327
Specifications
Configuration:
 • AARB-B
 • 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 (11.125 m)
Length50 ft 6 in (15.392 m)
Width9 ft 1 in (2.769 m)
Height12 ft 8 in (3.861 m)
Loco weight73 long tons (74.2 t; 81.8 short tons)
Fuel capacity500 imp gal (2,300 L; 600 US gal)
Prime moverSulzer 6LDA28-B
GeneratorBTH generator, type RTB 15656
Traction motorsD5151–D5175, four BTH traction motors
others: four AEI 253 AY traction motors DC
TransmissionDiesel electric
MU working Blue Star
Train heatingSteam (when present)
Train brakes25001 – 25082: Vacuum 25083 – 25247: Air and Vacuum (Dual Braked)
Performance figures
Maximum speed90 mph (145 km/h)
Power outputEngine: 1,250 hp (932 kW) @750 rpm
Tractive effortMaximum: 39,000 lbf (170 kN) to 45,000 lbf (200 kN)
Brakeforce38 long tons-force (380 kN)
Career
OperatorsBritish Railways
NumbersD5151–D5299, D7500–D7677; later 25001–25327
NicknamesRats
Axle load classRoute availability 4
Retired1984–1987
Disposition20 preserved, 307 scrapped

The British Rail Class 25, also known as the Sulzer Type 2, is a class of 327 diesel locomotives built between 1961 and 1967 for British Rail. They were numbered in two series, D5151–D5299 and D7500–D7677.[1]

The first 25 locos became known as Class 25/0 and were built at BR Darlington Works. The Class 25/1 locomotives were built at Darlington and BR Derby Works. The Class 25/2 locomotives were built at Derby with some built at Darlington. The final batch of locomotives were designated Class 25/3 and built by Derby Works and Beyer, Peacock and Company of Manchester.

  1. ^ "25 Bo-Bo". Brdatabase.info. Retrieved 4 August 2022.