British Rail Class 125

British Rail Class 125
Class 125 unit leaving Broad Street in April 1969
In service	1958–1977
Manufacturer	BR Derby
Number built	20 three-car sets
Number preserved	Nil
Formation	DMBS-TS-DMS
Capacity	266 second-class, no first
Operator(s)	British Rail
Specifications
Car length	64 ft 0 in (19.51 m) over body
Width	9 ft 4 1⁄2 in (2.858 m)
Height	12 ft 9 1⁄2 in (3.899 m)
Maximum speed	70 mph (113 km/h)
Weight	Power cars: 39.0 long tons (39.6 t; 43.7 short tons) Trailers: 32.0 long tons (32.5 t; 35.8 short tons)
Prime mover(s)	Two 238-brake-horsepower (177 kW) Rolls-Royce C8NFLH
Power output	952 bhp (710 kW) for 3-car set
Transmission	Hydraulic, Twin-disc (Rolls-Royce) torque converter
Multiple working	Orange Star
Track gauge	4 ft 8 1⁄2 in (1,435 mm)

This article is about the class of first-generation DMU. For the InterCity 125, see British Rail class 43.

The Class 125 was a design of three car Diesel Multiple Unit built by British Rail in 1958. They were high-density units, externally very similar to the Class 116. They were built specifically for the Lea Valley Line based at Stratford, but were displaced to the ECML suburban lines out of Kings Cross when the Lea Valley Line received over head electrification. The class were all withdrawn in 1977 when the ECML suburban lines received 25kV overhead electrification, and none survive to this day. Like many first-generation DMU classes, they never carried their 125xxx TOPS set numbers.

They were delivered in an unlined medium shade of Brunswick green with white cab roofs and yellow speed whiskers. The whiskers were replaced during the early 1960s by split yellow warning panels, one either side of the central character train describer which remained green.

During the mid 1960s rail blue appeared, and white cab roofs were gradually dispensed with and buffer beams became black. Initially the yellow warning panels were expanded to cover the complete lower front of the driving cabs and later the whole cab fronts became yellow.