British Rail Class 22

North British Type 2 diesel-hydraulic
British Rail Class 22

D6343 with Hymek D7072 at Old Oak Common, 1965

Type and origin Power type Diesel-hydraulic Builder North British Locomotive Co. Build date 1959–1962 Total produced 58

Specifications Configuration: ​  • Whyte B-B  • UIC B'B' Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Wheel diameter 3 ft 6 in (1.067 m) Minimum curve 4.5 chains (300 ft; 91 m) Wheelbase bogies 8 ft 6 in (2.59 m) bogie centers 23 ft (7.0 m) total34 ft 6 in (10.52 m) Length 46 ft 8 1⁄2 in (14.237 m) Width 8 ft 8 in (2.64 m) Height 12 ft 10 in (3.91 m) Loco weight D6300–D6305: 68 long tons (69 t) D6306–D6357: 65 long tons (66 t) Fuel capacity 450 imp gal (2,000 l; 540 US gal) Prime mover D6300-D6305, NBL / MAN L12V18/21A 1,000 bhp (750 kW) at 1445 rpm D6306-D6357, NBL / MAN L12V18/21BS 1,100 bhp (820 kW) at 1530 rpm Transmission Hydraulic: Voith / NBL LT.306r MU working D6300–D6305: ■ Orange square D6306–D6357: ◆ White diamond Train heating 1,000 pounds (454 kg) per hour steam generator 500 imp gal (2,300 l; 600 US gal) capacity Loco brake Vacuum controlled air brake, hand brake

Performance figures Maximum speed 75 mph (121 km/h) Tractive effort 38,000 lbf (170,000 N) @ 25% adhesion

Career Operators British Railways Numbers D6300–D6357 Nicknames Baby Warship Axle load class GWR: ●Blue BR: Route availability 4 Retired 1967–1972 Disposition All scrapped

Sources: except where noted

The British Rail Class 22 or "Baby Warship" was a class of diesel-hydraulic locomotives designed for the Western Region of British Railways and built by the North British Locomotive Company. They were very similar in appearance to the Class 21 diesel-electrics. The nickname Baby Warship related to the similarity in appearance (and internal equipment) to the British Rail Class D20/2 or Class 41 Warship Class.

D6300 was introduced to traffic in 1959 and deliveries continued through until 1962. The Class 22s were allocated to Bristol Bath Road, Laira Plymouth, Newton Abbot and Old Oak Common. The majority of the class always operated in the West of England, on a range of local passenger and freight work, with smaller numbers of the later units operating on local work in the Bristol and around London Paddington (notably moving empty carriages between the main station and Old Oak Common yard).

Initially the locomotives had some problems with engine and transmission faults, but could be returned to North British Locomotive Works (NBL) for repair under the contractual agreement. By 1961, reliability had improved, but with the more powerful Hymeks and Warships now being available, the locomotives were displaced onto more secondary duties, including work on the former Southern Region lines west of Exeter. By the mid 1960s, the locos had settled down to give reliable service, with availability over 85%.

NBL went bankrupt in 1962 and, by the late 1960s, withdrawn locomotives were being used to provide spares. Attrition was inevitable and the withdrawals, which had commenced in 1967, finished with the withdrawal of 6333, 6336, 6338 and 6339 in December 1971. Ex-London Midland Region Class 25 diesel-electrics were drafted in as replacements. One Locomotive (D6319) was purchased by a private individual from BR, but it was cut up at Swindon before the buyer could retrieve it. Class 42 D821 Greyhound was offered instead and became the first ex-BR diesel locomotive to enter preservation. An engine which ran in D6332 has been preserved in full working order, at the SRPS in Bo'ness.