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The Growth of the Southern Electric Network, Pre-Grouping and Grouping

by Richard Bell and Stephen Grant


The Constituent Companies

Four major railways were amalgamated in 1923 to form the Southern Railway (SR): the London and South Western Railway (LSWR), the London Brighton and South Coast Railway (LBSCR), the South Eastern Railway (SER), and the London Chatham and Dover Railway (LCDR).

Having exhausted each other financially by competition and duplicated routes to exploit the lucrative market for travel between London through the Channel ports to Europe, the SER and the LCDR had formed a working union in 1899, under which the networks of both were operated as one system under the name South Eastern and Chatham Railway (SECR), managed by a single set of chief officers advising and answering to a joint committee of directors from both companies.

Since there were no coalfields in these railways' territories (until the East Kent field was opened up after 1900, proving somewhat disappointing) little heavy industry developed. The primary source of income for these railways was therefore passenger traffic and the social and economic influences of London were crucial to its development.

These railway companies were the first to light upon that symbiosis between development of railway networks and the spread of suburbs which has become characteristic of great cities world-wide. From the 1850s they developed dense networks of local lines radiating from London into what was then open country, knowing that as they did so the surrounding land would be quickly developed for housing. One of the side-effects of this intensive development is that the subsequent development of deep level tube railways focused primarily on the under-exploited potential to the north, east and west of London .

In addition, as money and free time for leisure spread through the expanding middle classes, these railway companies encouraged excursions and longer visits to to the many coastal resorts and other places of recreation. The idea of residence outside London and the suburbs was soon urged upon the better-off, for First Class passengers were particularly to be welcomed.

By 1900 street tramways worked by horses had already been seen to draw some short-distance urban passengers away from the railways, but the sudden and rapid development of electric tramways in London and the suburbs seriously upset matters. Wherever electric trams and (a little later) motorbuses appeared, large numbers of short-distance passengers deserted the railways, particularly in the inner suburbs. For example, passenger numbers on the LBSCR South London Line declined by more than half between 1904 and 1909, and the SECR experienced similar or greater losses at inner suburban stations. The LSWR was also troubled by electric trams, and by the newly electrified Metropolitan District Railway.


The LBSCR seems to have sensed the danger quickly. In 1901 the company's Chief Engineer was sent to study electrified railways in Italy . Certain Directors persuaded the Board in favour of electric traction, both for suburban traffic and for the LBSCR's relatively short main lines, and general powers to electrify were obtained in 1903. The consulting engineer Philip Dawson was engaged to advise on electrification of the whole suburban network, and in 1904 recommended that the high-voltage single-phase alternating current system using overhead contact wires, then being developed in Germany , should be used, as the most suitable system for eventual electrification of the main lines. He also recommended that the in the first instance the South London Line between Peckham Rye and Battersea Park should be converted as a trial.

The main contract for this work was awarded in 1905 to the German firm Allgemeine Electricitäts Gesellschaft (AEG), and in the following year a second contract added extensions to London Bridge and to Victoria , to enable a fully commercial public service over the whole route. Current was to be obtained from a public supply undertaking, and was to be fed to the contact wires at 25 Hertz and 6600 Volts. A car shed and workshop was built west of Peckham Rye, in the vee of the divergence of the Sutton and South London lines.

Public electric service began on the South London Line on 1 December 1909 after eleven months of trials. Traffic began to recover at once, rising by 50% within the first month and doubling by April 1910, whereupon the Board decided upon immediate further electrification.

Electric services from Victoria via Streatham Hill to Crystal Palace began on 12 May 1911, and on 1 March 1912 from London Bridge via Tulse Hill to Crystal Palace and (mainly in peak hours) to Streatham Hill, Clapham Junction and Victoria. The route beyond Crystal Palace through Norwood Junction to Selhurst was also electrified to give access to a second and larger depot and workshop at Selhurst. Some trains running to and from this depot carried passengers between Crystal Palace and Norwood Junction.

Work on more extensions was interrupted by the outbreak of war in August 1914 which aborted all contracts with AEG, but was resumed on a limited scale in 1922 under new contracts with British firms, with the agreement of the other railways which were to merge in the Southern Railway. These final extensions of the a.c. network, from Balham via Streatham Common to Coulsdon and to Sutton, were brought into service by the SR on 1 April 1925.


The LSWR gained some experience of electric traction from the Waterloo and City Railway, which it worked from opening in 1898 and absorbed in 1906.

It was also able to observe the operation of Metropolitan District Railway electric trains over its own lines from Putney Bridge to Wimbledon and Hammersmith to Richmond , which the Underground Electric Railways Company, controlling the MDR, had electrified by agreement with the LSWR in 1905. The LSWR was nominal owner of the fixed electrical installations on its lines, but the Underground Company installed and maintained these, operated the substations, and supplied the energy.

Neverthertheless, the LSWR hesitated over electrification of its own services, and did not decide to proceed until 1912, then started the work for a first stage. Direct current at 600 Volts was to be used, supplied via an outside top-contact conductor rail and returned via the running rails.

The war delayed but did not halt the scheme, and the routes comprising stage 1 were turned over to electric traction during 1915-16:

  • To Wimbledon via East Putney on 25 October 1915 (entailing the separation of the installations on the Putney Bridge - Wimbledon line from the Underground electrical network and their incorporation in the LSWR's, with modifications to provide both fourth rail and running rail current return)
  • The Kingston Roundabout and to Shepperton on 30 January 1916
  • The Hounslow Loop on 12 March
  • To Hampton Court on 18 June
  • To Claygate on 20 November 1916.

Electrification of further routes was deferred. Traffic began to increase immediately, and rose rapidly after the war ended, to such an extent that shortage of rolling stock led to the electric service to Claygate being suspended from 1 June 1919.


The SECR had obtained powers to electrify in 1903, but the constitutional complications of the working union and the past financial records of the two companies made it unlikely that new capital could be raised at that time on terms which would not disadvantage existing shareholders. It was decided instead to reduce the inner suburban services in order to free track and terminal capacity for the development of more profitable outer suburban operations. In 1921 the possibility of Government assistance for projects which would give work to the engineering industry led to the SECR proposing electrification of most of its lines within 30 miles of London .

It was intended to use a "three wire" direct current system, whereby each track would have two protected conductor rails, one between and one outside the running rails. One conductor rail would be energised at 1500 Volts above earth and the other at 1500 Volts below, giving the advantage of a voltage-difference of 3000 while needing insulation and clearances to earth only for 1500 Volts. In a train unit with two motorcoaches, one motorcoach would draw current from the positive conductor rail and return it to the running rails, and the other would draw approximately the same current from the running rails and return it to the negative conductor rail. (The same principle was in successful use at that time in Paris on the Nord-Sud Metro lines 12 and 13, but using an overhead wire and a third rail, at +600/-600 Volts.)

Progress with this project before the amalgamation was blocked for two reasons: the SECR opposed itself to Government policy by wishing to build its own generating station; while the other participants in the coming amalgamation fought against the future Southern Railway being encumbered with a third distinctive and incompatible electrical system. However, much of the financial and engineering preparation by the SECR enabled the SR to get on with the much needed electrification of ex-SECR suburban lines very quickly after the grouping.

By the end of the First World War the railways of Britain were in a weak financial state, with backlogs of maintenance and renewals, with staff shortages and facing sharp increases in costs and increased competition from road transport. The Government seriously considered nationalisation but the eventual decision, enshrined in the 1921 Railways Act, was compulsory grouping of 120 pre-1914 railway companies into four systems, of which the Southern Railway was one.

Southern Railway

So far as the newly formed Southern railway was concerned, the Board concurred with the chief officers that electrification of all the suburban lines was necessary as soon as possible.

The third rail system has its disadvantages - the live conductor rail is a safety hazard, particularly in sidings and depots and it is susceptible to icing in severe weather. Also gaps in the conductor rail can cause a slow-moving electric locomotive, or even a short multiple unit train, to stall "gapped" with none of its pickup shoes in contact with a live rail as it traverses a complex junction, for example when departing from a major terminus.

Nevertheless, of the three systems developed by the constituent companies the LSWR's 660V d.c. third rail system required the least capital investment per track mile and was the least disruptive to install. Also, a substantial part of the south-western suburban network was already electrified on this system.

Accordingly the Southern’s Board decided in 1926 that the ex-SECR suburban routes would be electrified on the d.c. third-rail system at 660 Volts after the LSWR pattern, that the ex-LSWR d.c. network would be extended, but that the partially completed extensions of the ex-LBSCR a.c. overhead system would be finished and brought into service, pending later conversion to the new standard DC system.

Suburban Electrification

Thus on 1 April 1925 a.c. trains began running from Victoria via Streatham Common to East Croydon and Coulsdon North and to West Croydon and Sutton. Only a year later, however, the SR Board accepted the chief officers' recommendations that all future electrification should be to the d.c. third-rail system, and that in order to obtain economies from unification the a.c. system should be abandoned.

New d.c. services were introduced on the Western Section from Waterloo to Dorking North and to Effingham Junction via Epsom, and to Guildford via Claygate and Effingham Junction on 12 July 1925. On the same day on the Eastern Section, third rail d.c. services started to operate from Victoria and from Holborn Viaduct via Penge East and Bromley South to Orpington and from St.Pauls (now Blackfriars) via Nunhead to Shortlands and to Crystal Palace (High Level).

Interim services from Charing Cross and Cannon Street to Orpington, Bromley North, Beckenham Junction, Hayes and Addiscombe began on 28 February 1926 (Cannon Street was closed for rearrangement from 5 to 28 June); and by all routes to Dartford from 6 June. The planned full service of electric trains from Charing Cross and Cannon Street to these destinations began on 19 July 1926.

Electrification of the entire Central Section suburban network on the d.c. third rail system, extending as far as Caterham, Coulsdon North, Tattenham Corner, Epsom Downs, and Epsom, and via Tooting to Wimbledon , followed quickly in 1928-29, and the a.c. system was then taken out of use.

From 25 March 1928 d.c. electric trains ran in existing timings from Charing Cross and Cannon Street to Tadworth and Caterham and from London Bridge to Crystal Palace via Forest Hill.

On 17 June 1928 a.c. trains ceased to run from London Bridge ; they were replaced by a comprehensive d.c. electric service:

  • From Charing Cross (outside peak periods) and London Bridge to Tattenham Corner and Caterham, supplemented in peak periods by trains between London Bridge and Coulsdon North.
  • From London Bridge to Epsom Downs via Forest Hill and West Croydon
  • From London Bridge via Crystal Palace or Streatham Common back to London Bridge
  • From London Bridge to Streatham Hill via Tulse Hill
  • Between London Bridge and Victoria via Clapham.

From 3 March 1929 a.c. trains from Victoria to Streatham Hill and Crystal Palace were replaced by new d.c. services from Victoria to Streatham Hill and Crystal Palace and onwards to West Croydon and to Beckenham Junction and by the extension in peak periods of London Bridge - Streatham Hill trains to Victoria.

On the same date new d.c. electric services began:

  • From London Bridge via Mitcham Junction and Sutton to Dorking North and Epsom Downs
  • From Victoria to Epsom via Mitcham Junction
  • From Holborn Viaduct to Wimbledon via Streatham, extended on 7 July 1929 over the new line to South Merton.

For the time being a.c. trains continued to run from Victoria to Selhurst, Coulsdon North and Sutton, but were replaced as d.c. trains became available until the last ran from Victoria to Coulsdon North at 00.10 am on 22 September 1929.

On 5 January 1930 the Holborn Viaduct - South Merton d.c. service was further extended over the newly completed Wimbledon and Sutton line and on to West Croydon, trains continuing on from there via Crystal Palace to Victoria.

Suburban electrification was rounded off for the time being on 6 July 1930 by:

  • Extension of a proportion of the Dartford electric services to Gravesend Central
  • Newly electrified services from Waterloo to Windsor via Richmond and in peak periods via Hounslow
  • Newly electrified services from West Croydon to Wimbledon via Mitcham.
Mainline Electrification

Attention then turned to electrification of the main lines to the South Coast , including local services in the coastal area, and to other places beyond the suburban zone:

  • To Brighton and Worthing in 1932-33
  • To Eastbourne and Hastings in 1935
  • To Portsmouth via Guildford and to Alton in 1937
  • To Bognor and Portsmouth via Horsham in 1938
  • To Reading and to Aldershot via Ascot
  • To Gillingham and Maidstone in 1939.

Some of these schemes also involved extensions of suburban electric services, for example, Staines to Weybridge in 1937, Dorking to Horsham in 1938 and Gravesend to Gillingham in 1939, while suburban-style trains were allocated to some of the South Coast local services.

In the same period there were a few small extensions which were purely enlargements of the suburban network: to Sevenoaks, the Nunhead to Lewisham link and from Woodside to Sanderstead in 1934-35, and the new line to Tolworth and Chessington (originally intended to go on to Leatherhead) in 1938-39.


As before 1923, electrification by itself, in providing clean, more reliable and punctual, more frequent and faster trains, drew in more passengers, and again stimulated the spread of the suburbs.

By 1939 most of the inner termini, and especially Charing Cross and Cannon Street , were near to handling as many trains in peak periods as they could accommodate, and on several lines passengers were beginning to complain of overcrowding. Crucially for a healthy net revenue, off-peak and weekend traffic was also buoyant.

When the London Passenger Transport Board was created in 1933, to take over the underground railways and all road passenger transport in and around London out to a radius of 25 to 35 miles, a shared revenue pool was set up among the LPTB and the four main line railways: in this, the LPTB's share was 62%, and the Southern Railway's was 25.5%, the other three main line railway companies together sharing only 12.5%.

The electrification schemes of the Southern Railway and its predecessors were justified on passenger traffic alone. The electrifications were carried out as economically as possible; worn running rails were used for the electrified third rail, existing semaphore signalling was retained wherever traffic densities did not require multiple aspect signalling - even the gas lamps were retained on many wayside stations!

Multiple-unit electric trains were used for main line as well as suburban services - the SR had no electric locomotives for revenue-earning service until 1941. Virtually all through trains to non-electrified lines, trains including non-passenger-carrying vehicles and freight trains remained steam-locomotive-hauled.

Wartime Suspensions

The Waterloo - Wimbledon via East Putney passenger service was suspended in 1941 and was never restored, although the route was still used by empty trains between Waterloo and Wimbledon depot.

Service on the Nunhead - Crystal Palace (High Level) branch was suspended from 1944 to 1946 and finally abandoned in 1954.