British Rail Class 123

British Rail Class 123
300px A mixed four car diesel-mechanical multiple unit formed from a class 123 driving motor corridor second, 2 class 124 trailer brake corridor seconds, and a class 123 driving motor corridor second number at Manchester Piccadilly on 10 March 1984.
In service	1963–1984
Manufacturer	Swindon Works
Number built	40 (Ten 4-car units)
Number scrapped	All
Formation	DMBSL-TCK-TSL[RB]-DMSK
Capacity	24 First class, 176 Second class seats (units with buffet 32 second class less)
Operator(s)	British Rail
Specifications
Car length
Width	9 ft 3 in (2.82 m)
Height
Maximum speed	70 mph (113 km/h)
Weight	146.75 long tons (149.10 t; 164.36 short tons)
Prime mover(s)	230 hp (172 kW), 2 per power car
Power output	920 hp (686 kW)
Bogies	B4
Multiple working	Blue Square
Track gauge	4 ft 8 1⁄2 in (1,435 mm)

The Class 123 was a design of Diesel Multiple Unit built for British Rail in 1963. They were built by British Rail at Swindon Works, and designed like all Swindon units as inter-city sets. Ten of the four-car sets were built and introduced in 1963. The units bear a visible similarity to the British Rail Class 309; however, there is no 'relation' here as the two types were built by different manufacturers for different markets.

Swindon-built DMUs, including the Class 123 and 124, had a structure and internal construction with much more in common with BR coaching stock (British Rail Mark 1) than they do with many DMU classes. The carriage underframes were longer (Mk1 standard main-line 63 ft 6 in (19.35 m) frames, vs the 57 ft 0 in (17.37 m) frames common to most 1st generation DMUs) and the units were provided with Mk1-style "Pullman" gangways instead of the "British Standard Gangways" fitted to most contemporary DMUs of the period. It was also unusual for a first-generation DMU to sport a front end gangway. None of these units survive today.

Tabel of orders and numbers

Lot No.	Type	Diagram	Qty	Fleet numbers	Notes
30703	Driving Motor Brake Open Second (DMBSL)	566	10	52086–52095	32 seats, 2 lavatories
30704	Driving Motor Corridor Second (DMSK)	574	10	52096–52105	7 compartments (56 seats), 2 lavatories
30705	Trailer Corridor Composite (TCK)	567	10	59818–59827	4 first class and 3 second class compartments: 24 & 24 seats; 2 lavatories
30706	Trailer Open Second with lavatory (TSL)	568	5	59235–59239	64 seats, 2 lavatories
30707	Trailer Buffet Second (TSLRB)	569	5	59828–59832	32 seats, 8 seats in buffet area, 1 staff lavatory

Further Use

One of the buffet cars, 59831 was rebuilt as a Class 309 AC EMU griddle car, and renumbered 69108. It replaced a griddle car that had developed an underframe fault

References

• Motive Power Recognition: 3 DMUs. Colin J. Marsden
• British Rail Fleet Survey 8: Diesel Multiple Units- The First Generation. Brian Haresnape

External links

• History of the Class 123s