4 COR History


Electric trains have been with us since 1879. However, 3142 is the only surviving British express main line electric train built before 1950.

Development of the Southern Electric System

During the 1930s the Southern Railway Company electrified most of its outer suburban railways and several main lines to and along the South Coast. On all lines the third rail and electric multiple-unit systems were used. Electric Multiple Units (EMUS) are permanently coupled sets of coaches in which electric traction motors are mounted on the bogies of certain carriages — known as motor coaches — in each unit, so there was no need for a separate locomotive, and a driving cab is provided at each end of the unit.

The Southern’s first main line electrification, to Brighton, came in 1933. This encouraged further schemes, the most extensive and expensive of which was that onwards from Surbiton, in outer London, to Portsmouth via Guildford, and to Alton. 96 route miles of line were electrified. Electric train services commenced on 4th July 1937. Almost a year later, on 3rd July 1938, electric trains also started running to Portsmouth via the Mid Sussex route through Horsham. This scheme involved a further 75 route miles.

The lines to Portsmouth benefited greatly from electrification. Traffic over the Direct Line, via Guildford, was particularly heavy, and the line sinuous and steeply graded. It had been difficult to work with steam power, but the gradients presented few problems for the electric trains.


The new Portsmouth express multiple-units, like 3142, were made up of four coaches, so that three units were required to form a twelve-coach train. On the Brighton line twelve coach trains consisted of two six coach units. On the Portsmouth line it would have been wasteful to have provided three buffet cars so, for the first time in Britain, gangways were provided between units so that passengers could reach the restaurant car from any part of the train. This feature of the trains led to the units’ official classification, 4COR, meaning four coach corridored unit.

4COR units consisted of two motor coaches flanking two intermediate trailers with the outer bogie of each motor coach carrying two axle hung traction motors. Each unit was gangwayed throughout with normal operation on fast trains with three sets in multiple. Various catering cars of Cor type stock have operated over the years — designated 4RES, 4BUF and 4GRI denoting Restaurant, Buffet and Griddle respectively.

The end gangways also led, indirectly, to another name. Southern electric trains were fitted with a panel — until then located on unit ends between the two forward windows—on which a letter or number could be displayed to indicate the train’s route. On the 4CORs the headcode indicator was placed where the offside front window would otherwise have been, as it was inconvenient to position it on the gangway door. This left only one forward window, that for the motorman, on the nearside. The resulting ‘one-eyed’ appearance and association with Portsmouth and the Navy, inspired the unofficial epithet ‘Nelsons’, though the units were also known as ‘Pompeys’.

Each unit comprised two motor coaches each incorporating a motorman’s cab, a guard’s van and saloon accommodation with 52 third class seats. Two English Electric traction motors were mounted on the bogie beneath the guard’s van. Between the two motor coaches were two unpowered trailer coaches, one being all third class with 68 seats and the other a composite with 30 first class and 24 third class seats. All seats in the trailer coaches were in compartments. Each trailer had a lavatory at both ends. Third class accommodation was later renamed second. Some units included a restaurant or buffet car, and were classified 4RES or 4BUF respectively.

The underframes and external panelling were of steel, but the body-frame was of hardwood and the roof was covered with canvas and pitch. Mounted on the underframes of each motor coach there was a motor-generator that provided current at 70V for all auxiliary circuits except the heating, which worked at 660V from the third rail supply. Westinghouse air brakes and English Electric electro-pneumatic control equipment were fitted.

29 4COR and 19 4RES units were constructed for the Portsmouth Direct line, and a further 26 4COR and 13 4BUF units for the Mid Sussex route.

The Last Years with British Rail

In 1963 the units on the Mid-Sussex line were replaced and the displaced 4CORs went to the Brighton line for rush-hour workings. In 1970 the units on the Portsmouth Direct line were also replaced and were transferred to the Waterloo — Reading line and to the Brighton Coastway lines. On 30th September 1972 the last ordinary passenger train operated by a 4COR unit was the 09.50 from Seaford to Brighton.