British Rail Class 43 (Warship Class)

British Rail Class 43
D852 'Tenacious' at Old Oak Common in 1964
Type and origin Power type Diesel-hydraulic Builder North British Locomotive Co. Serial number 27962–27994 Build date 1960–1962 Total produced 33
Specifications Configuration: ​  • UIC B'B' Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Wheel diameter 3 ft 3 1⁄2 in (1.003 m) new Minimum curve 4.5 chains (91 m) Wheelbase bogie 10 feet 6 inches (3.20 m) bogie center distance 37 ft 9 in (11.51 m) total 48 ft 3 in (14.71 m) Length 60 ft 0 in (18.29 m) Width 8 ft 10 in (2.69 m) Height 12 ft 9 1⁄2 in (3.90 m) Loco weight 79.50 long tons (80.78 t; 89.04 short tons) Fuel capacity 800 imp gal (3,600 l; 960 US gal) Prime mover MAN L12V 18/21, 2 per locomotive Engine type V12 four stroke diesel Cylinders 12 Cylinder size 180 mm × 210 mm (7.087 in × 8.268 in) (bore x stroke) Transmission Hydraulic, Voith/NBL LT.306r MU working ◆ White Diamond Train heating Steam, 940 imp gal (4,300 l; 1,130 US gal) capacity Loco brake Vacuum controlled air, hand brake (?) Train brakes Vacuum
Performance figures Maximum speed 80 mph (130 km/h) Power output Engines: 1,100 bhp (820 kW) × 2 Tractive effort Maximum: 49,030 lbf (218 kN)
Career Operators British Railways Numbers D833–D865 Nicknames "Warship" Axle load class Route availability 7 (RA 6 from 1969) Retired 1969–1971
Technical details : B.R.33003/91 except where noted

The British Rail Class 43 diesel-hydraulic locomotives were built by the North British Locomotive Company (NBL) from 1960–1962.

The D800 series diesel-hydraulic 'Warship Class', of B-B wheel arrangement, was constructed by two different builders. Those locomotives built by British Railways at Swindon Works were originally numbered D800-D832 and D866-D870. They were allocated Class 42 under the 1968 classification system, while those built by the North British Locomotive Company (NBL) were originally numbered D833-D865 and allocated Class 43. Because of their early withdrawal dates, neither the Swindon- nor the NBL-built locomotives carried TOPS numbers. More detail on factors common to both types can be found in the article on the Swindon-built British Rail Class 42.

The NBL-built D800s differed mechanically from the Swindon-built batch: the Swindon locomotives used Maybach engines connected to Mekydro hydraulic transmissions whereas the NBL-built examples used MAN engines and Voith transmissions. NBL had entered into an arrangement with the German company MAN AG in the early 1950s to market MAN's engine designs in the UK: NBL were anxious to enter the diesel locomotive market, especially once it became apparent that British Railways would be seeking large quantities of such locomotives when the "Modernisation Plan" was announced. MAN were equally keen to obtain a slice of the UK market for themselves. The first results of this collaboration were the D600-D604 locomotives which failed to take advantage of the weight-saving potential of light alloy stressed-skin construction allied to hydraulic transmissions.

No further examples of this design were ordered but NBL then received an order for 33 locomotives to a more advanced design, the D800 design drawn up by Swindon Works in turn derived from the original German Krauss-Maffei V200 design. The prime mechanical components of these were two MAN L12V18/21B diesel engines, each rated at 1,100 hp (820 kW) at 1530 rpm and coupled to a Voith LT306r hydraulic transmission; each engine/transmission combination drove one bogie. Unlike the Mekydro four-speed transmissions in the Swindon-built locomotives, the Voith was only a three-speed design but was chosen because it kept compatibility with D600-4 and because NBL already had a licence to manufacture it. Whereas the Swindon-built locomotives had all their engines and transmissions supplied by the German manufacturers (albeit with ten engines and three transmissions supplied as kits of parts for the British licensee to re-assemble) the engines and transmissions required for D833-65 were all built by NBL.