British Rail Class 29

class of 20 Bo′Bo′ 1350hp diesel-electric locomotives rebuilt from Class 21

The British Rail Class 29 consisted of 20 diesel locomotives which were rebuilt from the North British Class 21. The original licence-built MAN engines of the Class 21s had proved unreliable, so in 1963 locomotive D6123 was sent to Paxman's Colchester works to receive a new Paxman Ventura V12 engine. A further 19 were re-engined in 1964–1965 at Polmadie Works, with other changes made at the same time. This included the fitting of four-character headcode displays in the nose ends. After rebuilding, they returned to service from Eastfield depot in Glasgow.

British Railways Class 29
Type and origin
Power typeDiesel-electric
BuilderNorth British Locomotive Company
Build date1958–1960
Rebuilt: 1963, 1965–1967
Total produced20
 • WhyteBo-Bo
 • UICBo'Bo'
Gauge4 ft 8 12 in (1,435 mm) standard gauge
Wheel diameter3 ft 7 in (1.092 m)
Minimum curve3.5 chains (70 m)
Wheelbase37 ft 0 in (11.28 m)
Length51 ft 6 in (15.70 m)
Width8 ft 8 in (2.64 m)
Height12 ft 8 in (3.86 m)
Loco weight73 long tons (74 t)
Fuel capacity460 imp gal (2,100 L; 550 US gal)
Prime moverPaxman Ventura
TransmissionDC generator, DC traction motors
MU working Red Circle
Train heatingSteam generator
Train brakesVacuum
Performance figures
Top speed75 mph (121 km/h)
Power outputEngine: 1,350 hp (1,010 kW)
Tractive effortMaximum: 45,000 lbf (200 kN)
Brakeforce50 long tons-force (498 kN)
Railroad(s)British Railways
NumberD6100–03/06–08/12–14/16/19, D6121/23/24/29/30/33/34/37
Axle load classRoute availability 6 (RA 5 from 1969)

Although these offered more power and much improved reliability over the original Class 21s, they did not survive much longer, due to their small class size and the use of a non-standard high-speed diesel engine. D6108 was withdrawn in May 1969 and scrapped by McWilliams of Shettleston in 1971, while the other 19 were withdrawn between April and December 1971 and scrapped at BR's Glasgow Works in 1971–72. No Class 21 or Class 29 locomotives survive today.