British Rail Class 315

British Rail Class 315
London Overground Class 315 No. 315811 at Hackney Downs
The refreshed interior of a London Overground Class 315
In service	1980 - present
Manufacturer	BREL York
Family name	BREL 1972 "PEP"
Constructed	1980 - 1981
Refurbishment	1st refurbishment All 61 sets 2004 - 2008 Bombardier Derby 2nd refurbishment London Overground and TfL Rail 2015 - 2016 Bombardier Ilford
Number built	61 trainsets
Formation	4 cars per trainset
Fleet numbers	315801 - 315861
Capacity	318 seats
Operator(s)	London Overground TfL Rail
Specifications
Car length	19.80 m (64 ft 11 1⁄2 in)
Width	2.82 m (9 ft 3 in)
Height	3.58 m (11 ft 9 in)
Maximum speed	75 mph (121 km/h)
Weight	127.5 t (125.5 long tons; 140.5 short tons)
Power output	656 kW (880 hp)
Electric system(s)	25 kV 50 Hz AC Overhead
Track gauge	1,435 mm (4 ft 8 1⁄2 in) standard gauge

British Rail Class 315 alternating current (AC) electric multiple units (EMU) were built by BREL York works from 1980 to 1981. They were the fifth and final variant of British Rail's then-standard 1972 design for suburban EMUs, which eventually encompassed 755 vehicles and five Classes (Class 313/314/315/507/508). Like the Glasgow-based Class 314 units, they are only able to operate from the 25 kV overhead line.

The fleet works inner-suburban TfL-run services on the Shenfield Metro for TfL Rail and the Lea Valley Lines for London Overground out of London Liverpool Street.

Each Class 315 unit is formed of four vehicles; some vehicles are attached to another set of four vehicles to make 8 vehicles. In the past, some further vehicles attached to another four to make 12 vehicles on long distance journeys, such as ones to Southend Victoria or Southminster (operated by Greater Anglia). The vehicles include: Driving Motor Standard Open (DMSO), Pantograph Trailer Standard Open (PTSO), Trailer Standard Open (TSO), and Driving Motor Standard Open (DMSO). Each DMSO carries four traction motors (315801-841 originally had Brush TM61-53 and 315842-861 had GEC G310AZ but these motors are interchangeable and nowadays any type can be found on any unit) rated at 110hp each and a main compressor and air reservoir which carries air for the brakes and suspension. The original pneumatic door system has been replaced by an all-electric door system. The PTSO carries the main and auxiliary transformers, batteries and battery charger, Stone Faiveley AMBR Mk.1 pantograph, vacuum circuit breaker and auxiliary compressor. The TSO carries no equipment other than that which is standard to all coaches.