British Rail Class 314

British Rail Class 313 electric multiple units were built by BREL at York Works between February 1976 and April 1977 and were the first second-generation EMUs to be constructed for British Rail. They were also the first British Rail units fitted with both a pantograph for 25 kilovolt AC overhead lines and shoegear for 750 volt DC third rail supply, and the first units in Britain to have Multi-Function couplers, which allow both physical coupling and also the connection of control electric and air supplies to be carried out without the need to leave the cab.

Description
The Class 313 fleet was developed following extensive trials with the prototype Class 445 "PEP" unit built in the early 1970s. The 313 is similar to its sister classes of Class 314 (Glasgow), Class 315 (Anglia suburban — east London), Class 507 (Merseyside) and Class 508 (Merseyside, formerly Southern Region).

Since they were originally designed for use on Great Northern Suburban Inner Suburban services from to  or, which included a section of 'tube' line built to take standard size trains between  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 Stone Faiveley AMBR 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 750 V DC supply, the traction supply for each motor coach is separate, whereas on conventional 750 V DC trains each coach in a unit is linked by a 750 V 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 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, and 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 25 kV AC supply provides a 750 V DC supply to the motor coaches, each of which is equipped with four 110 hp GEC G310AZ traction motors, two per bogie. When on 750 V DC supply, each motor coach draws its supply directly through its shoe gear.

The Class 313s are fitted with Series Wound DC GEC G310AZ traction motors, which are controlled by a camshaft controlled resistance system, with series and parallel motor groupings and weak field steps. Originally the heating in the motor coaches was provided by passing air over the hot traction and braking resistors, in addition to conventional heaters, though this feature is no longer in use and the pneumatic dampers have been disabled. First Capital Connect and Southern units are now retro-fitted with cab air conditioning equipment.

Class 313s are fitted with rheostatic braking (disabled on London Overground) in addition to conventional 3 step air-operated disc braking; during braking if wheelslide is detected by the WSP (WheelSlide Protection) rheostatic braking is disabled and the disc-braking comes into effect. Additionally units operated by First Capital Connect are equipped with sanding equipment. Unlike some other classes of DMU/EMU additional brake force is not available when the an emergency brake application is initiated and is the equivalent force of a step 3/full service application, however WSP is disabled when making an emergency application.

In addition to the primary suspension (formed of rubber chevron spring and oil dampers), secondary suspension is provided by air 2 air bellows per bogie, the air flow into each bellow is controlled independently by a levelling valve and arm assembly which will allow the suspension to inflate/deflate when the weight of the coach is increased or decreased by passenger loading. The air suspension system is also linked to the braking system via a Variable Load Valve (VLV), this will give an increase in air brake pressure when the coach is more heavily loaded to compensate for the additional weight.

The DMS B coach is equipped with an MA set (Motor Alternator) which runs on 750 V DC from the AC/DC changeover switch whereby the transformer and rectifier provide the supply when on 25 kV working and by the shoegear directly when on 3rd rail working. The MA provides power for the following equipment:


 * 415 V (AC) - Headlight (DC lamp supplied through an additional transformer), traction/braking resistor cooling fan, coach heater fans (the heaters themselves run on 750 V DC).
 * 240 V (AC) - Cab heater fan, cab fresh air fan, thermostat fans, appliance sockets.
 * 110 V (DC) - Control supply, battery charging, train lighting, cab air conditioning, CCTV system.

Individual vehicles are numbered as follows. All units have standard class seating only.
 * 62529-62592 - DMSO
 * 71213-71276 - PTSO
 * 62593-62656 - BDMSO

As built, the sliding doors of these units were individually opened by the passengers. Once the driver had stopped the train and the guard had activated the master door release, a passenger could move the door handle gently sideways which would operate a switch controlling the individual door opening circuit. Unfortunately many people did not wait for the guard's release, and gave the handle a much harder tug, which could open the door even if the train had not stopped. Concerns over passenger safety led to the removal of the handles from March 1977. In recent years, push-buttons have been fitted which serve the same purpose as was intended for the handles.

Modifications led to a certain amount of renumbering and reclassification. All 64 units were originally provided with shoebeams on the inner bogie of each motor coach, which was sufficient for their original third-rail duties between Drayton Park and Moorgate. Some units became surplus, and four were transferred to the Colchester-Clacton/Walton route, which has no DC sections; these four units had the shoegear removed, and were renumbered from 313061-4 to 313096-9; this happening in 1987. However, following an accident involving one of these units at Walton on the Naze in August 1987, they were subsequently replaced by Class 310s in 1988. 313s had also worked on the Colchester-Walton/Clacton route between 1981 and 1983. 16 others had shoegear fitted to the outer bogies in addition, and were transferred to the Euston-Watford route where there are long gaps in the conductor rails; these, 313001-016, were not renumbered, but were classified 313/1, the unmodified units becoming 313/0 - prior to this the entire class were simply designated class 313, without subdivisions.

Operations
Following privatisation, the Class 313 fleet was divided between two franchises - Silverlink and West Anglia Great Northern (WAGN)

First Capital Connect
West Anglia Great Northern inherited the majority of the class, with a fleet of 41 units operating inner suburban services out of Moorgate and London King's Cross, to Welwyn Garden City, Hertford North, Letchworth Garden City and Stevenage. Although the majority of the route is 25 kV AC overhead line equipment, the route between Moorgate and Drayton Park is third rail 750v DC (the line was formerly part of the London Underground Northern Line and although built to full loading gauge there is insufficient clearance to add catenary). Trains bound for Moorgate approach Drayton Park on a falling gradient, drawing power via the pantograph until a trackside Automatic Power Control (APC) magnet opens the Vacuum Circuit Breaker (VCB) on the roof of the train, cutting off power. This prevents the driver from powering into the tunnel with the pantograph still raised if he should forget to change from AC power. After coasting to a stand at Drayton Park the driver lowers the pantograph and changes over to DC traction power. On journeys from Moorgate the traction power is maintained into Drayton Park for the rising gradient, since if the driver forgets to change traction mode to AC no damage will occur to the train. Once the train is at a stand the driver selects AC traction and raises the pantograph.

From 1 April 2006, the Great Northern (GN) franchise merged with Thameslink to form the Thameslink/Great Northern franchise, which was won by First Capital Connect.

An additional three 313/1 units transferred to First Capital Connect from London Overground in September 2010 to augment the existing Class 313/0 fleet. These units have been repainted into the Urban Lights livery and lightly refreshed internally. They retain their original low-backed seating, although the upholstery has been altered to First Capital Connect standard. Despite receiving modifications which have made them mechanically identical to the 313/0s, they have not been renumbered. Unit 313134 was named "City of London" at Moorgate on 9 December 2010 by Michael Bear, the Lord Mayor of London.

Southern
Nineteen Class 313s displaced by Capitalstars  on London Overground services are being transferred to Southern, where they are replacing Class 377/3 Electrostars on East and West Coastway services from Brighton.

These Class 313s were repainted at Wolverton works. The full refurbishment began around June 2010 and included new flooring and carpet, new seating, improved disabled and cycle space and the fitting of a Passenger Information System. Refurbishment work took place at Wabtec Doncaster. Additional modifications were carried out at Stewarts Lane TMD including the installation of cab air-conditioning, sanding equipment, a 750V busline, shore supply sockets and the removal of inboard shoegear. Recommissioning exams began in February 2010 taking place at Stewarts Lane, which included the removal of tripcocks.

As of September 2010, 313214 had been delivered from Wabtec Doncaster to Selhurst Depot with a refurbished interior. The unit was awaiting installation of the new 2+2 high backed seating. Bogie work was also being undertaken on this unit at Selhurst and its pantograph has been removed. The remainder of the Southern 313 subsequently had their pantographs removed as they were for use on DC-only lines. Removal of the pantographs has rendered the AC traction equipment redundant.

Since January 2010, units 313101, 313108 and 313109 had been providing driver training in rotation as a six-car formation, with single units leaving for Stewarts Lane TMD as required for scheduled maintenance. They were joined by Southern-liveried 313203 from March. The first three 313s in Southern livery were released from Wolverton Works in February 2010 and are now berthed at Stewarts Lane TMD, awaiting recommissioning and modifications. These units are being renumbered into the 313/2 series as they are expected to have their AC overhead equipment removed. Unit 313206, released from Wolverton on 14 April 2010, was the first to boast Coastway branding, promoting the lines the 313s are intended to run on as, "Your local links along the South Coast", with local pictures and a list of destinations. It was joined in the same livery by 313214 and 313216 during May 2010.

The Class 313s commenced operations with Southern on 23 May 2010, providing a two trains-per-hour service between Brighton and Seaford, as well as selected trains between Brighton and Lewes, Hove, West Worthing and Littlehampton. From 13 December 2010, their scope of operation expanded to include stopping services from Brighton to Portsmouth Harbour and the Littlehampton to Bognor Regis shuttle.

The decision to use Class 313 units on the Coastway lines has been controversial, as the 313s are much older than the 377s and have fewer on-board passenger facilities.

The rail union RMT criticised the move and many publications including the BBC have questioned the introduction of 35-year-old trains with no lavatories in place of much newer units. These trains are deployed on services that operate over predominantly short distances, such as Brighton to Hove and Brighton to Seaford, and some longer (but stopping) services that provide predominantly local links which run alongside Class 377 units on the parallel faster services. The economic justification of operating new 100mph air conditioned Class 377 trains on routes like the Hove to Brighton shuttle was always questionable however. And many other areas local train services operating over short (or even medium) distances do not have toilets (eg London Underground Metropolitan Line, Class 455 units (Southern/SWT) Class 508 units (Merseyrail)

The introduction of 313 services on the coastway routes facilitates the delivery of additional capacity on high demand suburban routes in South London where 10 car trains services are to be introduced (combined with a programme of platform lengthening).

Longer trains will also be introduced on the East Grinstead route providing longer trains on the key Victoria / East Croydon corridor. Longer trains on this route will be introduced in late 2011.

London Overground
Silverlink inherited a fleet of 23 units, mainly operated as Silverlink Metro services on the North London, West London and Watford DC Lines and they were regulars on the St. Albans Abbey–Watford Junction branch line between 1988 and 2007, when the Silverlink franchise ended.

In 2007, these trains were used on services transferred to London Overground, which replaced the Silverlink Metro franchise. London Overground branding was added, and some seats were removed to provide additional standing room. They were replaced by Class 378 trains, which feature longitudinal seating to improve standing room.

The final day of scheduled Class 313 operation on the North and West London Lines was 19 February 2010, although units were used ad-hoc substituting for unavailable 378/0 units. By August 2010 only two Class 313s, 313121 and 313123, were still in service with London Overground, as the Class 378/2 Capitalstars were by then in use on the Watford DC Line.

The final Class 313 (313123) operated on Monday 13 September 2010, the last passenger working being the 23.10 Willesden Junction - Clapham Junction. Both 313121 and 313123 were moved from Willesden to Wolverton on Friday 17 September for repainting, thus ending 313 operation with London Overground.

One 313/1, unit 313121, has not yet been accepted by a new operator and is at Wolverton works as of 15 December 2010. It is the last 313 to retain the distinctive Silverlink livery.

European Rail Traffic Management System trials on the Hertford Loop
Network Rail plans to use Eversholt Rail owned unit 313121 as a test vehicle for ERTMS on the Hertford Loop, where it hopes to have the facility running by 2014 or earlier. The plan involves resignalling a 5.5 mile section of the double track route to allow exisiting services to use only one line, freeing the other for ERTMS tests.

Named units
A number of 313s have been named over the years. They are as follows:


 * 313020 - Parliament Hill (denamed)
 * 313054 - Captain William Leefe Robinson V.C.
 * 313101 - Silvertown (denamed)
 * 313109 - Arnold Leah (denamed)
 * 313111 - London TravelWatch (denamed)
 * 313116 - Nikola Tesla (denamed)
 * 313134 - The Hackney Empire (denamed)
 * 313134 - City of London