British Rail Class D16/2

British Rail Class D16/2
10201 at Tring, 1959
Type and origin Power type Diesel-electric Builder BR Ashford Works (2) Brighton railway works (1) Order number SR Order 3441 Build date 1950 (10201/10202) 1954 (10203)
Specifications Configuration: ​  • UIC (1′Co)(Co1′)  • Commonwealth 1Co-Co1 Gauge 4 ft 8+1⁄2 in (1,435 mm) standard gauge Wheel diameter Driving: 3 ft 7 in (1.092 m) Idling: 3 ft 1 in (0.940 m) Minimum curve 4.5 chains (297.00 ft; 90.53 m) Wheelbase 55 ft 6 in (16.92 m) Length 63 ft 9 in (19.43 m) Width 9 ft 3 in (2.82 m) Height 13 ft 1 in (3.99 m) Loco weight 133 long tons (135 t; 149 short tons) Fuel capacity 1,150 imp gal (5,200 L; 1,380 US gal) Lubricant cap. 16 imp gal (73 L; 19 US gal) Coolant cap. 280 imp gal (1,300 L; 340 US gal) Prime mover English Electric 16SVT Traction motors English Electric 526A, 6 off Cylinder size 10 in × 12 in (254.0 mm × 304.8 mm) Train heating Steam Train brakes Vacuum
Performance figures Maximum speed 90 mph (140 km/h) Power output Engine: 10201/2: 1,750 bhp (1,300 kW) 1,600 bhp (1,200 kW) from 1957 10203: 2,000 bhp (1,500 kW) At rail : 10201/2 1,300 bhp (970 kW) Tractive effort 10201/2: 48,000 lbf (213.5 kN)
Career Operators British Railways Class 10201/2: D16/2, later 16/9 10203: D20/3, later 20/9 Power class 10201/2: 6P5F, later 5P5F 10203: 7P6F, later 6P6F Numbers 10201–10203 Axle load class RA 6 Withdrawn 1963 Disposition All scrapped

British Railways Class D16/2 was a class of prototype diesel locomotives built by British Railways at Ashford Works and introduced in 1950–1951, with a third example being introduced in 1954. They had been designed by Oliver Bulleid for the Southern Railway and were authorised in February 1947^[1] but did not appear until after nationalisation. The diesel engine and transmission were supplied by English Electric, but the Bulleid influence was obvious. The box-like body style closely resembled Bulleid's electric locomotives and was quite different from the usual English Electric style, typified by British Rail Class D16/1 which in turn was strongly influenced by contemporary American design.^[2]

Unusually for pioneer British diesels, 10201 and 10202 were originally specified (prior to alteration of gear ratios to improve tractive effort when operating as mixed-traffic units) with a top speed of 110 mph (180 km/h) rather than the 90 mph (140 km/h) of 10203,^[3] pre-dating the three-figure maximum speeds of the Deltic and Class 50 designs by some years.

Percy Bollen's bogie design^[4] and the power train of 10203 were taken almost unmodified for the first ten production British Rail Class 40s but with a more traditional English Electric design of body with prominent noses and louvred side panels.