Southern Electric History and Infrastructure Part 2 - Southern Railway
In 1923, the Southern Railway was created, grouping the London & South Western Railway, South Eastern & Chatham Railway and London Brighton & South Coast Railway, into one company. In short, as Southern Railway top management was dominated by former London & South Western Railway staff, the London & South Western Railway system prevailed - 660V dc third rail. Undoubtedly this cheap and robust system has proved its worth over the following years although the London Brighton & South Coast Railway may well have had the more technically advanced system in line with today's main line standards, while the 1500V dc system would have allowed through working to the French rail network by the channel tunnel then in planning. No SR route was electrified at 1500V and conversion of the LBSCR overhead system to third rail started in 1928. The last ac trains ran between Coulsdon North and Victoria in 1929 and the projected main line ac extensions to Brighton and the south coast were never implemented.
So the Southern Electric had come into being a 660V dc third rail network with electric multiple unit passenger trains. The Southern Railway introduced new standards, first from around 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 British Rail 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 world's first four aspect signalling was implemented between Holborn Viaduct and Elephant & Castle. In 1925 the Guildford New Line 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 75mph main line corridor unitsthe 6 car Cit, Pan and Pul sets with 1800hp Metropolitan-Vickers or British Thomson Houston equipment on the Sussex scheme. The three five car all Pullman Bel units were the world's 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 accommodation 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 motortrailertrailertrailertrailermotor, the four coach sets motortrailertrailermotor, and the two coach set motortrailer. A notable relic from this era is Bil unit 2090 is now part of the National Railway Museum collection. Unfortunately none of the fine 6 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 8 motors per 6 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 developments 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 750V dc Co-Co electric locomotives was introduced. At the 1948 nationalisation, all of the "Big Four" had advanced plans or actual builds of locomotives alternative to steam traction. The GWR was pursuing the gas turbine route with its UKdesigned 18100 from Metropolitan Vickers following the Swiss built 18000 from Brown Boveri. The LNER had 1500V 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 Co-Co electric 20001 and 20002 and 1Co-Co1 diesels 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 motorgeneratorflywheel arrangement to maintain tractive power across third rail gaps and were used by BR SR on Central Division boat train workings. 10201 and 10202 were first used on South West Division 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 into service in 1949. These, to date, are the only double deck passenger vehicles to have operated in the United Kingdom 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.