British Rail Class 313

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Class 313/0, no. 313064 at London King's Cross on 8th February 2003. This unit is painted in WAGN family travelcard advertising-livery.

Class 313/1, no. 313114 arriving at Clapham Junction on 30th October 2004 with a service from Willesden Junction. This unit is painted in Silverlink Metro livery.

Unit 313033 sports a purple WAGN livery at Stevenage, albeit with FCC decals.

The front of class 313/1, no. 313110 at Kew Gardens.

Class 313 electric multiple units were built by BREL at York Works from 1976-77, these being the first second-generation EMUs to be constructed for British Rail. They were also the first dual-voltage units to be built, capable of drawing power via 25 kV AC overhead, or 750 V DC third-rail, and the first units in Britain to have fully automatic couplers which allowed both physical coupling and also the connection of control electric and air supplies to be carried out without the need to leave the cab.

Since they were originally designed for use on Great Northern Suburban Inner Suburban services from Welwyn Garden City to Moorgate, which included a section of 'tube' line built to take standard size trains between Drayton Park and Moorgate, they are built to a slightly smaller loading gauge than conventional trains. They are standard length and width, but the roof is somewhat lower, most noticeable due to the lack of a distinctive "well" for the pantograph on the centre coach. Also, they have to comply with regulations for underground trains, such as having doors at each end of the train for evacuation onto the tracks, and when on 750V DC supply, the traction supply for each motor coach is separate, whereas on conventional 750v DC trains each coach in a unit is linked by a 750v bus line. Due to this, each motor coach has shoe gear on both bogies, whereas normally it would only be provided on the leading bogie. They are also fitted with trip-cocks which are struck by a raised train-stop arm at red signals and will apply the brakes if the train passes one. The units used by Silverlink Metro have been modified so that the bus line works when running on third rail, due to long section gaps on parts of the North London Line where they operate.

[edit] Description

The Class 313 fleet was developed following extensive trials with the prototype Class 445 "PEP" unit built in the early 1970s. Outwardly the 313 is similar to its sister classes Class 314, Class 315, Class 507 and Class 508 which are used in Glasgow, East of London and Merseyside, respectively.

The three-car units were originally numbered in the range 313001-064. Each unit is formed of two outer driving motors, and an intermediate trailer equipped with a pantograph. This is a reversal of the practice started in the 1960s where the motors and if applicable pantograph would be carried on an intermediate vehicle, with the outer vehicles being un-powered driving trailers. Part of the reason was to simplify the equipment to allow dual voltage operation, an also to keep down weight by spreading heavy equipment (the transformer and motors) between vehicles. The intermediate trailer carries the pantograph and also a transformer and rectifier, which when on 25kV AC supply provides a 750v DC supply to the motor coaches, each of which is equipped with 4 small traction motors, 2 per bogie. When on 750v DC supply, each motor coach draws its supply directly through its shoe gear.

The Class 313s are fitted with Series Wound DC traction motors, which are controlled by a camshaft controlled resistance system, with series and parallel motor groupings and weak field steps. They are fitted with rheostatic braking. During the winter, the heating in the motor coaches is provided by passing air over the hot traction and braking resistors, as well as conventional heaters.

Individual vehicles are numbered as follows.

• 62529-62592 - DMSO
• 71213-71276 - PTSO
• 64593-64656 - BDMSO

All units have standard class seating only.

[edit] Current operations

Following privatisation, the Class 313 fleet was divided between two franchises. These are described below.

[edit] First Capital Connect

West Anglia Great Northern (WAGN) inherited the majority of the class, with a fleet of 41 units. They operate inner suburban services out of Moorgate and King's Cross, to Welwyn Garden City, Hertford North, Letchworth and Stevenage. Although the majority of the route is 25kV AC through overhead cables the line between Moorgate and Drayton Park is 3rd rail DC only. (The line was formally part of the Northern Line and although built to full loading gauge there is insufficient clearance to add catenary - see the Northern City Line page for more information on the history of this line). Trains bound for Moorgate arrive at Drayton Park drawing power via the pantograph. At Drayton Park the driver presses a single button that lowers the pantograph and completes all the necessary electrical switching to proceed on DC power. On journeys from Moorgate the procedure is reversed again at Drayton Park.

[edit] Silverlink

Silverlink inherited a fleet of 23 units. They mainly operate Silverlink Metro services, such as:

• London Euston - Watford Junction
• North London Line (Richmond - Stratford - North Woolwich)
• West London Line (Clapham Junction - Willesden Junction)
• Watford Junction - St. Albans Abbey (This line is branded as part of Silverlink County)

By 2010, these units will have been replaced by Electrostar trains as part of the transfer of the Silverlink Metro service to the new London Overground which will enter its first phase in November 2007.

From 1st April 2006 the WAGN franchise merged with Thameslink, the new combined franchise is First Capital Connect

[edit] Fleet details

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British Rail Class 313