Southern Electric history and infrastructure

The Southern Electric is the name given to the low voltage direct current top contact third rail electrified railway system in the south sast of the UK. The Southern Electric Group is dedicated to the past history and up to date happenings on this system, the largest third rail electrified network in the world. Todays Southern Electric extends in Kent, Sussex, Surrey, Berkshire, Hampshire and even into Dorset. London terminals connected are Charing Cross, Cannon Street, Blackfriars, London Bridge, Waterloo and Victoria. 750 V DC is todays standard, developed from the original LSWR concept. The Southern Railway adopted the LSWR system in preference to those devised by the LBSCR and SECR transforming the original third rail inner suburban network into a long distance and main line network. The pre-WW2 network reached Brighton, Hastings and Portsmouth on the south coast. The SR introduced standardisation of electrical equipment using components supplied by English Electric with the Southern Region of British Railways continuing in the same direction. BR SR extended the Southern Electric network to the Kent Coast in the early 1960s and reached Bournemouth later in the decade. Technical advances both in the electric traction field and in rolling stock construction into the 1980s saw a move away from the traditional camshaft controlled Mk.1 bodied trains. The 1990s brought privatisation and the eventual division of the Southern Electric amongst six new train operating companies

Origins and the LSWR
LBSCR and SECR
Southern Railway
BR Southern Region
Network South East
Train operating companies
Channel Tunnel
Power supply

The third rail low voltage system adopted by the London & South Western Railway for its initial surface electrication followed the system it used for its Waterloo & City tube line between Waterloo and Bank. In turn, the Waterloo & City project was influenced by the City & South London tube line - the catalyst for the Southern Electric.

The London Brighton & South Coast Railway adopted a very different electrification system. Using another German concern, this time AEG, as the electrical contractor using power supplied by the local authority. Following testing on the South London line in 1909 public services commenced there and to Crystal Palace by 1911. A high voltage distribution system of 25 Hz at 6666.66 V was used which by 1925 the overhead system had reached Coulsdon and Sutton. In 1901 the separate London Chatham & Dover Railway and South Eastern Railway came under the single management control of the South Eastern & Chatham Railway. It considered various proposals before the outbreak of World War I but it was not until 1919 that the SECR decided to adopt a third and fourth rail DC system. A side contact system of 3000 V differential with +1500 V on the outer third rail and -1500 V on the inner fourth rail was planned. Power would come from a dedicated generating station at Angerstein Wharf. Routes planned for electrification were from the Charing Cross, Cannon Street, Holborn Viaduct and Victoria London terminals to all routes to Dartford, and to Addiscombe, Oprpington, Hayes and Bromley North. However this scheme did not come to fruition.

So the Southern Electric had come into being - a 660 V DC third rail network with electric multiple unit passenger trains. The SR introduced new standards first from c.1929 using Metropolitan Vickers and British Thomson Houston control systems, traction motors and lineside equipment. Later, c.1935, English Electric traction equipment was adopted, a standard lasting into the 1980s. The EE507 traction motor was to become almost universal across the later BR Southern Region. From 1925 electric trains reached Orpington from Victoria and Holborn Viaduct and by late 1926 most of the former SECR project was completed but at the lower voltage. Not only were the routes electrified, now electric colour light signalling was introduced on dense traffic routes. In 1926 the worlds first four aspect signalling was implemented between Holborn Viaduct and Elephant & Castle. In 1925 Guildford had been electrified while in 1930 the newly constructed Wimbledon to Sutton route was opened with electric trains from the start. The same year, Windsor, Wimbledon to West Croydon and Dartford to Gravesend also saw the start of electric passenger services.

The 1930s saw the SR expand the Southern Electric from its London area suburban system into a main line network. In the early part of the decade, the electrified third rail reached the Sussex coast to Brighton in early 1933, Hastings and Worthing on the Central section, and then the Portsmouth Direct line on the Western section. The 1933 scheme saw the introduction of forty 75 mph main line corridor units - the six car Cit, Pan and Pul sets with 1800 hp Metropolitan-Vickers or British Thomson Houston equipment on the Sussex scheme. The three five car all Pullman Bel units - the worlds first all Pullman electric train sets for exclusive use on the Brighton Belle service. While the Bel units were all Pullman, the Pul sets consisted of one Pullman and five ordinary cars. Pan units were six car ordinary cars but with a pantry (buffet) car with Pullman attendant. The Cit units were similar to Pul but with all first class accomodation for use on City Limited business services. Regular interval express, or fast, services to the Sussex coast were worked by twelve car trains generally formed 6Pan+6Pul. Intermediate stations were served by 4Lav and 2Bil sets for semi-fast and slow traffic. The six car units were formed motor-trailer-trailer-trailer-trailer-motor, the four coach sets motor-trailer-trailer-motor, and the two coach set motor-trailer. A notable relic from this era is Bil unit 2090 now part of the National Railway Museum collection. Unfortunately none of the fine six car express units survives today.

Although gangwayed within each set, the early 1930s express units retained full width driving cabs and it was not possible for passengers or even crews to pass between adjacent coupled sets. The late 1930s Cor units featured through gangways and were of lighter construction with English Electric equipment. The massively constructed Pul/Pan type motor coaches with two motor bogies each (therefore eight motors per six coach set) each gave way to vehicles with only one powered bogie per motor coach. Express trains of up to twelve cars were operated by three units coupled together, one unit with catering equipment ( 4Res later 4Buf and 4Gri ) and two 4Cor sets. Cor units survived in British Railways traffic until 1972 with the Southern Electric Group saving unit 3142 for preservation along with other similar vehicles. Stopping services were provided for by the 2Hal units similar to the preceding 2Bil but of more spartan passenger comfort. Technical developements before the outbreak of World War II included the greater use of steel in place of wood in coach body construction and the last built batches of 2Hal and 4Lav units were of all steel construction.

Despite electrification, the Southern Railway was still reliant on steam traction for freight traffic over electrified routes but in 1941 the first of three 750 V DC CoCo electric locomotives was introduced. At the 1948 nationalisation, all of the "Big Four" had advanced plans or actual builds of alternative locomotives to steam traction. The GWR was pursuing the gas turbine route with its UK designed 18100 from Metropolitan Vickers following the Swiss built 18000 from Brown Boveri. The LNER had 1500 V DC electric locomotive E26000 - built for the Manchester Sheffield Wath (working on loan to The Netherlands) together with various former NER locomotives in store. The LMSR had its own built main line diesel twins - 10000 in traffic and 10001 near completion - but no electric locomotives. Only the Southern Region had both with its CoCo electric 20001 and 20002 and 1CoCo1 diesel 10201 and 10202 working or well advanced. These were later joined by a third of each - 20003 and 10203. The electric locomotives used an ingenious motor-generator-flywheel arrangement to maintain tractive power across third rail gaps and were used by BR SR on CD boat train workings. 10201 and 10202 were first used on SWD Bournemouth and Exeter line passenger work, together with 10000 and 10001 on loan, until all were removed to the LMR never to return to the SR.

The first rolling stock types delivered after the cessation of hostilities were high density four car suburban units with all steel bodies. 4Sub unit 4732 of this batch has been retained for preservation The SR also experimented with double deck electric units with the two prototype 4DD sets placed in service in 1949. These, to date, are the only doube deck passenger vehicles to have operated in the UK despite being common on other European systems. Of novel interior design, the complete eight car train managed the same overall passenger carrying capacity as a ten car train of conventional stock. However, extended station dwell times for passenger alighting and boarding were unacceptable. Two 4DD cars survive today.

The post war nationalisation of Britains "Big Four" companies - the Southern Railway, the Great Western Railway, London Midland & Scottish Railway, and the London & North Eastern Railway - into British Railways in 1948 saw all of the Southern Electric fall into British Railways Southern Region. The BR SR organisational structure of the three South Eastern, South Western and Central Divisions continued to reflect the pre-grouping SECR, LSWR and LBSCR companies which had been little altered by the Southern Railway. The first rolling stock developement was the evolution of Sub into EPB, together with the standardisation of the electropnuematic brake. EPB followed the experiment with the 4DD double decker suburban units. The 4DD concept was aimed at continuing to operate trains of just eight coaches length and although the two prototype units remained in traffic until 1971 no production series followed. Instead, on the SED platform lengths were extended for ten car operation by EPB stock. Sub and EPB stock with slam doors at every bay typified the Southern Electric post-war suburban scene for almost fifty years. Examples of Sub EPB and DD coaches are all preserved

The 1955 Modernisation Plan for British Railways initiated the replacement of steam traction. The major project for BR SR at this time was the Kent Coast scheme extending the third rail beyond Gillingham and Orpington to Dover, Folkestone, Ramsgate and Margate. Four car Cep and Bep corridored express units based on the standard BR Mk.1 body were introduced together with two car Hap non-gangwayed units for stopping services. Other forms of motive power were ten single car MLV luggage cars provided with traction batteries for short trips away from the third rail, and 24 HA electric locomotives. The HAs, later BR Class 71, E5001-5024 were also fitted with the flywheel booster control system and with pantographs for use at low speed on a few freight sidings equipped with trolley wires. The MLV vehicles were primarily designed to provide additional luggage accomodation on 12Cep boat trains, while the HA locomotives were also used on important Continental boat train workings. The Pullman Golden Arrow service, and the Night Ferry through Wagons Lits sleeping cars were handled by these locomotives.

1963 saw the introduction of Cig and Big express units. These were an important technical developement beyond their Cep and Bep predecessors in that whereas the Kent Coast units were formed with two driving motor coaches (each with only the outer bogie motored), the new trains had a single intermediate non-driving motor coach with driving trailers at the outer ends. Both Cig and Cep stock were still in total powered by four EE507 250 hp traction motors. The 1963 batch was first used on the Central Division to displace the early 1930s trains while a later 1970 built batch was destined for the South Western Division to replace the last 1930s built Cor units. The Southern Electric Group's 3142 was one of the trains withdrawn at this time. The express Cig trains, and the technically similar Vep outer suburban trains continued to be built to Mk.1 standard while similar locomotive hauled trains utilised Mk.2 bodies. This legacy of Mk.1 stock is in 1998 causing the present train operating companies problems as the regulatory bodies now consider this type of train to not meet adequate safety standards. There is particluar concern about the crash worthiness of this type of coach in even low speed impacts.

1967 saw the completion of the last major SR third rail electrification operated by outwardly conventional trains. However, the Bournemouth line 4Rep and 4TC trains were very different technically. Through services beyond the limit of electrification at Bournemouth to Weymouth were retained and a novel form of push-pull working was devised. From the London (Waterloo) end of the train, one 4Rep tractor unit would push two 4TC trailer units to Bournemouth. Here, the 4Rep would simply un-couple from the rear while a push-pull equipped diesel loocmotive would couple to the front end. The diesel would pull the 4TC units to Weymouth (and push on the return to Bournemouth). The 4Rep waited for the next arriving train from Weymouth, with the diesel detaching from the rear, and pulled the 4TC units back to London. The 4Rep were the first deviation away from the EE507 traction motor being fitted with the more powerful EE546. One 4Rep had eight such motors totalling 3200 hp, to allow it to push or pull two unpowered 4TC sets with no loss of performance. This system was replaced in 1986 when new Class 442 trains were introduced.

In 1971 three new sliding door high density suburban units were delivered to the SR.

Network SouthEast was created with the responsibility of running inner and outer suburban and local passenger services in a region approximately 100 miles radius of London. The origins of NSE lie in the organisational changes from 1984 when British Rail started to move from a regionally organised production led system to business sectors. Originally this sector was known as London & South East and devised a beige and orange livery which was applied only to CEP stock on the Southern Electric. NSE encompassed routes and services from the Southern, Western, London Midland and Eastern Regions and introduced the bright red, blue and white "toothpaste" livery for its trains. Possibly the most significant NSE led developement affecting the Southern Electric was the introduction of the Networker Class 465 and 466 units. These incorporate three phase traction motors in the first move away from the traditional DC motor.

The privatisation of the nationalised British Railways created 27 passenger train operating companies. Three of these, Connex South Eastern, Connex South Central and South West Trains are near direct descendants of the South Eastern, Central and South Western traffic divisions of BR Southern Region from 1948, of the Southern Railway from 1923, and of the pre-grouping SECR, LBSCR and LSWR companies. Three other train operating companies, Gatwick Express, Thameslink and Island Line were also formed out of NSE and BR SR, while other operators also run passenger, and freight, services through the Southern Electric area. For further information go here for an overview of the present operation of each. The SEG magazine Live Rail available to members is an ideal way to remain updated on the services and trains operated by these companies.

The Channel Tunnel itself is not strictly part of the Southern Electric system due to its basis on private sector funding and operation by an independant company. However, the significant freight and passenger channel tunnel traffic flows fall directly within the Southern Electric area. Traditional channel ports passenger boat train flows were withdrawn when the tunnel opened, together with cessation of the Dover-Dunkirk train ferry. Dover Western Docks passenger station was also a casualty of the tunnel. The channel tunnel was constructed by a consortium of civil engineering concerns known as Trans Manche Link. TML at one time operated the UK's third largest railway when its 600 mm gauge construction railway system was in full operation. On completion of the main railway was taken over by Eurotunnel who directly operate the shuttle truck and tourist services under the Le Shuttle name, and lease pathways to the British and French railways for passenger and freight services.

Through all these operational, technical and political changes in nearly a century of Southern Electric operation, few electrified lines have been closed. The Crystal Palace High Level service was suspended then withdrawn after WW2 while the Haywards Heath to Horsted Keynes line was axed in the notorious cuts of the 1960s. (Horsted Keynes was a junction station with the non-electrified line which now forms part of today's Bluebell Railway) In more recent times the former SECR Holborn Viaduct London terminal station was closed for replacement by the through City Thameslink station as part of a major office developement. Dover Western Docks was closed as a direct result of the completion of the Channel Tunnel, while both the Addiscombe to Elmers End and West Croydon lines were closed for replacement under the Croydon Tramlink project.

Power for the Southern Electric system was purchased by the former British Rail from the former Central Electricity Generating Board and taken from the national grid at various locations. A network of lineside cables distributes power, mostly at 33 kV 50 Hz three phase AC, to lineside substations. These are generally located at intervals of about 3.5 miles along each line, with intermediate track paralleling huts. Substations on the Bournemouth are 4.5 miles apart due to the higher than usual voltage on that line. At each substation the alternating voltage is stepped down by transformers and the current rectified to direct current. It is then fed through switchgear to conductor rails, each laid on porcelain insulators 1 ft 4 in outside one of the running rails on each electrified track. Conductor rail is made of high conductivity steel and weighs between 100 and 150 lb/yd. Current is returned from the trains to the lineside substations through the running rails. Substations vary in design considerably, due to their differing ages, but all are unmanned and remotely supervised from one of ten electric control rooms located at strategic points throughout the region. Nominal line voltage varies from area to area and actual line voltage can fluctuate considerably. All types of multiple unit train subsequent to 1936 stock are able to accept the differing voltages without any special arrangements. Obviously, performance is superior on the lines with higher voltages. Until 1939 lines were electrified at 600 V except for some in the inner suburban area. Lines in Kent south and east of Gillingham, Sevenoaks and Maidstone, that is those electrified by British Railways, have been at 750 V since electrification. The Bournemouth line west of Pirbright Junction (Brookwood) is electrified at 850 V. The Isle of Wight line is electrified at 630 V while the Waterloo & City [now part of the London Underground] remained at 660 V. The Isle of Wight system is unusual in that power is purchased from the Southern Electricity Board, it obviously being impractical to connect the island to mainland power cables. The Southern's other island, Sheppey, is connected to the main lineside network by means of a cable under the River Swale, but power can be obtained from the South Eastern Electricity Board at Queenborough in emergency. In order to ensure that the lineside power supply equipment is not overloaded, all electric multiple units are allocated a "conductor rail current index number". This number is directly proportional to the maximum current likely to be drawn from the line by the stock concerned and in most cases is equal to the number of (250 hp) traction motors on the unit. The total index number must not exceed 16.