British Rail Class 25

Specifications
Specifications
Configuration:;
• AAR	B-B
• UIC	Bo'Bo'
• Commonwealth	Bo-Bo
Gauge	4 ft 8+1⁄2 in (1,435 mm) standard gauge
Wheel diameter	3 ft 9 in (1.143 m)
Minimum curve	4.5 chains (91 m)
Wheelbase	36 ft 6 in (11.125 m)
Length	50 ft 6 in (15.392 m)
Width	9 ft 1 in (2.769 m)
Height	12 ft 8 in (3.861 m)
Loco weight	73 long tons (74.2 t; 81.8 short tons)
Fuel capacity	500 imp gal (2,300 L; 600 US gal)
Prime mover	Sulzer 6LDA28-B
Generator	BTH generator, type RTB 15656
Traction motors	D5151–D5175, four BTH traction motors; others: four AEI 253 AY traction motors DC
Transmission	Diesel electric
MU working	★ Blue Star
Train heating	Steam (when present)
Train brakes	25001 – 25082: Vacuum 25083 – 25247: Air and Vacuum (Dual Braked)

Type and origin
Type and origin
Power type	Diesel-electric
Builder	British Railways' Crewe Works, Darlington Works and Derby Works; Beyer, Peacock & Co.
Build date	1961–1967
Total produced	327

British Rail Class 25
British Rail Class 25
	Class 25/3 in BR blue at Manchester Victoria in 1980.
Power type
Type and origin
Power type	Diesel-electric
Builder	British Railways' Crewe Works, Darlington Works and Derby Works; Beyer, Peacock & Co.
Build date	1961–1967
Total produced	327
Configuration:;
Specifications
Configuration:;
• AAR	B-B
• UIC	Bo'Bo'
• Commonwealth	Bo-Bo
Gauge	4 ft 8+1⁄2 in (1,435 mm) standard gauge
Wheel diameter	3 ft 9 in (1.143 m)
Minimum curve	4.5 chains (91 m)
Wheelbase	36 ft 6 in (11.125 m)
Length	50 ft 6 in (15.392 m)
Width	9 ft 1 in (2.769 m)
Height	12 ft 8 in (3.861 m)
Loco weight	73 long tons (74.2 t; 81.8 short tons)
Fuel capacity	500 imp gal (2,300 L; 600 US gal)
Prime mover	Sulzer 6LDA28-B
Generator	BTH generator, type RTB 15656
Traction motors	D5151–D5175, four BTH traction motors; others: four AEI 253 AY traction motors DC
Transmission	Diesel electric
MU working	★ Blue Star
Train heating	Steam (when present)
Train brakes	25001 – 25082: Vacuum 25083 – 25247: Air and Vacuum (Dual Braked)
Maximum speed
Performance figures
Maximum speed	90 mph (145 km/h)
Power output	Engine: 1,250 hp (932 kW) @750 rpm
Tractive effort	Maximum: 39,000 lbf (170 kN) to 45,000 lbf (200 kN)
Brakeforce	38 long tons-force (380 kN)
Operators
Career
Operators	British Railways
Numbers	D5151–D5299, D7500–D7677; later 25001–25327
Nicknames	Rats
Axle load class	Route availability 4
Retired	1984–1987
Disposition	20 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.

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.