British Rail Class 46

The British Rail Class 46 is a class of diesel locomotive. They were built from 1961–1963 at British Railways' Derby Works and were initially numbered D138-D193. With the arrival of TOPS computer system they were renumbered to Class 46. Fifty-six locomotives were built. The first was withdrawn in 1977 and all of them were withdrawn by 1984.

Derby Type 4 British Rail Class 46
Class 46
Type and origin Power type Diesel-electric Builder British Railways’ Derby Works Build date 1961–1963 Total produced 56
Specifications Configuration: ​  • Whyte 1Co-Co1  • UIC (1Co)'(Co1)' Wheel diameter 3 ft 9 in (1.143 m) Minimum curve 3.5 chains (70 m) Wheelbase 59 ft 8 in (18.19 m) Length 67 ft 11 in (20.70 m) Width 8 ft 10+1⁄2 in (2.71 m) Height 12 ft 10 in (3.91 m) Loco weight 138 long tons (140 t) Fuel capacity 790 imp gal (3,600 L; 950 US gal) Prime mover Sulzer 12LDA28-B MU working ★ Blue Star Train heating Steam generator Train brakes Vacuum
Performance figures Top speed 90 mph (145 km/h) Power output Engine: 2,500 bhp (1,864 kW) At rail: 1,962 hp (1,463 kW) Tractive effort Maximum: 55,000 lbf (245 kN) Brakeforce 63 long tons-force (628 kN)
Career Railroad(s) British Railways Number D138–D193; later 46001–46056 Nicknames ‘Peak’ Axle load class Route availability 7

The Class 46 design was structurally the same as the earlier Class 45 build, and had the same Sulzer engine. It differed in the fitment of a Brush generator and traction motors, in place of the Crompton Parkinson equipment fitted to the Class 45.