British Rail Class 312

British Rail Class 312
British Rail Class 312
	First Great Eastern Class 312 at Kirby Cross in 2004
	Inside a Class 312 unit before refurbishment
In service	1975–2004
Manufacturer	British Rail Engineering Limited
Order no.	30863 (312/0 BDTSOL vehicles); 30864 (312/0 MBSOs); 30865 (312/0 & /1 TSOs); 30866 (312/0 DTCOLs); 30867 (312/1 BDTSOLs); 30868 (312/1 MBSOs); 30870 (312/1 DTCOLs); 30891 (312/2 BDTSOLs); 30892 (312/2 MBSOs); 30893 (312/2 TSOs); 30894 (312/2 DTCOLs);
Built at	Holgate Road, York
Family name	BR First Generation (Mark 2)
Replaced	Class 125
Constructed	1975–1978
Number built	49
Number preserved	0; (2 vehicles from 1 unit);
Successor	Class 317; Class 321/4; Class 323; Class 360;
Formation	4 cars per unit:; BDTSOL-MBSO-TSO-DTCOL;
Diagram	ED212 (312/0 MBSOs); ED213 (312/1 MBSOs); ED214 (312/2 MBSOs); EE305 (all DTCOLs); EF213 (all BDTSOLs); EH209 (all TSOs);
Fleet numbers	As built:; 312/0: 312001–312026; 312/1: 312101–312119; 312/2: 312201–312204; As rebuilt:; 312/0: 312701–312726; 312/1: 312781–312799; 312/2: 312727–312730;
Capacity	As built: 322 seats; (25 first-class, 297 standard);
Operators	British Rail; c2c; Central Trains; First Great Eastern;
Depots	Bletchley; Clacton; Hornsey;
Specifications
Car body construction	Steel
Train length	256 ft 8+1⁄2 in (78.245 m)
Car length	Drv. cars: 65 ft 1+5⁄8 in (19.853 m); Int. cars: 65 ft 4+1⁄4 in (19.920 m);
Width	9 ft 3 in (2.82 m)
Height	12 ft 4+1⁄2 in (3.772 m)
Floor height	3 ft 9 in (1.14 m)
Doors	Hinged, manually operated ("slam")
Wheelbase	Motor bogies: 9 ft 0 in (2.74 m); Trailer bogies: 8 ft 6 in (2.59 m); Over bogie centres:; 46 ft 6 in (14.17 m);
Maximum speed	312/0 & /1: 90 mph (140 km/h); 312/2: 75 mph (121 km/h);
Weight	BDTSOL: 35 tonnes (34 long tons; 39 short tons); DTCOL: 33 tonnes (32 long tons; 36 short tons); 312/0 MBSO: 56 tonnes (55 long tons; 62 short tons); 312/1 &/2 MBSO: 55.5 tonnes (54.6 long tons; 61.2 short tons); TSO: 30.5 tonnes (30.0 long tons; 33.6 short tons);
Traction motors	4 × English Electric 546A
Power output	1,080 hp (810 kW)
HVAC	Electric heating
Electric system(s)	6.25 kV 50 Hz AC overhead (312/1s only); 25 kV 50 Hz AC overhead (all);
Current collector(s)	Pantograph
UIC classification	2′2′+Bo′Bo′+2′2′+2′2′
Bogies	Motor cars: BREL BP14; Trailer cars: BREL BT8;
Minimum turning radius	231 ft 0 in (70.41 m)
Braking system(s)	Electro-pneumatic
Safety system(s)	AWS
Coupling system	Drop-head buckeye
Multiple working	Within class, and with Class 310
Seating	Transverse
Track gauge	1,435 mm (4 ft 8+1⁄2 in) standard gauge

The British Rail Class 312 alternating current (AC) electric multiple units (EMUs) were built between 1975 and 1978 for use on outer-suburban passenger services. It was the last class of multiple unit to be constructed with the British Rail Mark 2 bodyshell, as well as the last class of multiple unit to be built with slam doors in Britain. These features contributed to their relatively early withdrawal at 25–28 years old, compared with a typical EMU life expectancy of 30–40 years.