British Rail Class 23

English Electric Type 2 British Rail Class 23
"Baby Deltic" D5902 at King's Cross, July 1966.
Type and origin Power type Diesel-electric Builder English Electric at Vulcan Foundry Build date 1959 Total produced 10
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 4 chains (80 m) Wheelbase 40 ft 6 in (12.34 m) Length 52 ft 6 in (16.00 m) Width 8 ft 10+3⁄4 in (2.71 m) Height 12 ft 8 in (3.86 m) Loco weight 74 long tons (75.2 t; 82.9 short tons) Fuel capacity 550 imp gal (2,500 L; 660 US gal) Prime mover Napier T9-29 Deltic Generator DC Traction motors DC Transmission Diesel electric MU working ★ Blue star Train heating Steam Train brakes Vacuum
Performance figures Maximum speed 75 mph (121 km/h) Power output Engine: 1,100 hp (820 kW) Tractive effort Maximum: 47,000 lbf (209.1 kN) Brakeforce 360 kN (36 long tons-force)
Career Operators British Railways Numbers D5900–D5909 Nicknames Baby Deltic Axle load class Route availability 5 Withdrawn 1968–1971 Disposition All scrapped, one new member being built

The British Rail Class 23 were a class of ten Bo-Bo diesel-electric locomotives built by the English Electric Company (EE) in 1959. The power unit used was a Napier Deltic T9-29 9-cylinder engine of 1,100 bhp (820 kW) driving an EE generator, which powered the four traction motors. They were numbered from D5900 to D5909.^[1]

The T9-29 diesel engine was a single, half-sized version of those used in the more powerful British Rail Class 55 'Deltic' locomotives, and the overall design and external appearance of the Class 23 was also similar to the Class 55, but much shorter, leading to their nickname of Baby Deltics.