British Rail Class 20

Specifications
Specifications
Configuration:;
• UIC	Bo′Bo′
• Commonwealth	Bo-Bo
Gauge	4 ft 8+1⁄2 in (1,435 mm) standard gauge
Wheel diameter	3 ft 7 in (1.092 m)
Minimum curve	3.5 chains (70 m)
Wheelbase	32 ft 6 in (9.91 m)
Pivot centres	24 ft 0 in (7.32 m)
Length	46 ft 9+1⁄4 in (14.256 m)
Width	8 ft 9 in (2.67 m)
Height	12 ft 7+5⁄8 in (3.851 m)
Loco weight	73 t (72 long tons; 80 short tons)
Fuel capacity	380 imp gal (1,700 L; 460 US gal)
Lubricant cap.	100 imp gal (450 L; 120 US gal)
Coolant cap.	130 imp gal (590 L; 160 US gal)
Prime mover	English Electric 8 SVT Mk.II
Generator	DC
Traction motors	D8000–D8049: EE 526/5D; Remainder: EE 526/8D;
Cylinder size	10 in (250 mm)
Transmission	Diesel electric
Gear ratio	63:17
MU working	★ Blue Star
Train heating	None
Train brakes	Vacuum, Dual or Air

Type and origin
Type and origin
Power type	Diesel-electric
Builder	English Electric at Vulcan Foundry and Robert Stephenson and Hawthorns
Build date	1957–1962, 1965–1968
Total produced	228

English Electric Type 1
British Rail Class 20
English Electric Type 1; British Rail Class 20;
	20134 & 20075 at Ryecroft Junction, 1978.
Power type
Type and origin
Power type	Diesel-electric
Builder	English Electric at Vulcan Foundry and Robert Stephenson and Hawthorns
Build date	1957–1962, 1965–1968
Total produced	228
Configuration:;
Specifications
Configuration:;
• UIC	Bo′Bo′
• Commonwealth	Bo-Bo
Gauge	4 ft 8+1⁄2 in (1,435 mm) standard gauge
Wheel diameter	3 ft 7 in (1.092 m)
Minimum curve	3.5 chains (70 m)
Wheelbase	32 ft 6 in (9.91 m)
Pivot centres	24 ft 0 in (7.32 m)
Length	46 ft 9+1⁄4 in (14.256 m)
Width	8 ft 9 in (2.67 m)
Height	12 ft 7+5⁄8 in (3.851 m)
Loco weight	73 t (72 long tons; 80 short tons)
Fuel capacity	380 imp gal (1,700 L; 460 US gal)
Lubricant cap.	100 imp gal (450 L; 120 US gal)
Coolant cap.	130 imp gal (590 L; 160 US gal)
Prime mover	English Electric 8 SVT Mk.II
Generator	DC
Traction motors	D8000–D8049: EE 526/5D; Remainder: EE 526/8D;
Cylinder size	10 in (250 mm)
Transmission	Diesel electric
Gear ratio	63:17
MU working	★ Blue Star
Train heating	None
Train brakes	Vacuum, Dual or Air
Maximum speed
Performance figures
Maximum speed	75 mph (121 km/h)
Power output	Engine: 1,000 hp (746 kW)
Tractive effort	Maximum: 42,000 lbf (186.8 kN); Continuous: 25,000 lbf (111.2 kN)@ 11 mph (17.7 km/h);
Brakeforce	35 long tons-force (349 kN)
Operators
Career
Operators	British Railways; Railfreight; Eurostar; Direct Rail Services; HNRC; Balfour Beatty;
Numbers	D8000–D8199, D8300–D8327; later 20 001–20 228
Nicknames	Chopper
Axle load class	Route availability 5
Withdrawn	1976–present
Disposition	6 in service, 22 preserved, remainder scrapped or in storage.

The British Rail Class 20, otherwise known as an English Electric Type 1, is a class of diesel-electric locomotive. In total, 228 locomotives in the class were built by English Electric between 1957 and 1968, the large number being in part because of the failure of other early designs in the same power range to provide reliable locomotives.

The locomotives were originally numbered D8000–D8199 and D8300–D8327. They are known by railway enthusiasts as "Choppers".