British Rail Class 127

British Rail Class 127
BR (Derby) Class 127 4-car Suburban DMU at St Pancras, 1975
In service	1959–1993
Manufacturer	BR Derby
Built at	Derby
Family name	First generation
Replaced	Steam locomotives and carriages
Constructed	1958–1959
Number built	30 sets (120 vehicles)
Number preserved	3 sets (8 vehicles)
Number scrapped	27 sets (112 vehicles)
Successor	Class 317
Formation	4-cars sets: DMBS + TSL + TS + DMBS
Fleet numbers	51591–51650 (DMBS) 59589–59618 (TSL) 59619–59648 (TS)
Capacity	DMBS: 78 TSL: 90 (2 lavatories) TS: 106
Operator	British Rail
Specifications
Car length	64 ft 0 in (19.51 m)
Width	9 ft 3 in (2.82 m)
Height	12 ft 4+1⁄2 in (3.772 m)
Maximum speed	70 mph (113 km/h)
Weight	DMS: 40 long tons (41 t; 45 short tons) TSL: 30 long tons (30 t; 34 short tons) TS: 29 long tons (29 t; 32 short tons)
Prime movers	Rolls-Royce C8NFLH, 2 per power car
Power output	476 hp (355 kW) per power car
Transmission	Hydraulic
Multiple working	■ Originally Blue Square but later changed to ▲Red Triangle
Track gauge	4 ft 8+1⁄2 in (1,435 mm)

The British Rail Class 127 diesel multiple units were built by BR Derby in 1959. Thirty 4-car units were built, formed of two outer driving motor vehicles, sandwiching two intermediate trailers which were classified class 186.

Replacement

The class 127 units operated one of the most intensive passenger services worked by diesel multiple units and, by the late 1970s, it was clear they needed replacing. It was therefore decided to electrify the Bedford line and replace the Class 127 units with new Class 317 electric multiple units. The class 127 units should have been withdrawn by 1982, however, delays with the new trains meant they had to struggle on in service until July 1983. This was largely due to an industrial dispute with the unions over Driver only operation, which resulted in the new electric trains being stored at Cricklewood depot for nearly a year, awaiting the resolution of the dispute.

Accidents and incidents

• On 10 October 1964, on an eight-car London St Pancras to Bedford service, a cardan shaft failed on rear car 51591 near Wilshamstead. The failed shaft pierced two fuel tanks, which then caught fire. One person was killed and four injured by jumping from the train. The fire caused only minor damage and was brought under control by the train crew and a railwayman passenger.

Preservation

This list is incomplete; you can help by adding missing items. (October 2026)

References

Further reading

• Burgoyne, Mick (March 1983). "DMUs with a difference". Rail Enthusiast. EMAP National Publications. pp. 14–17. ISSN 0262-561X. OCLC 49957965.

External links

Wikimedia Commons has media related to British Rail Class 127.

• Llangollen Railcar Group - owners of preserved DMUs on Llangollen Railway.
• Midland Railway Trust Railcar Group - owners of 51591+59609+51625+51610.
• History of the Class 127s