British Rail Class 405

The Southern Railway (SR) and the British Railways (Southern Region) (BR(S)) used the designation Sub to cover a wide variety of electric multiple units that were used on inner-suburban workings in the South London area. The designation ‘Sub’ was first officially used in 1941 to refer to newly built 4-car units. However, during the 1940s large numbers of earlier ‘ 3-Car Suburban Sets’ were increased to four cars by the addition of an 'Augmentation' trailer, and became part of the 4-Sub category. The SR and BR (S) continued to build or else rebuild 4-car units to slightly different designs which became part of the 4-Sub Class. Many of these later examples survived in passenger use until late 1983, by which time British Rail had allocated to them TOPS Class 405.

History

3-Car Suburban Sets

In 1923, the Southern Railway inherited 84 3-car suburban electric multiple units from the London and South Western Railway (LSWR), dating from 1914. These could be enhanced by 24 2-car trailer sets coupled between two units, creating 8-car formations. Over the next 18 years the SR acquired a further 516 3-car sets. These were either new; rebuilt from steam stock inherited from the LSWR, the London Brighton and South Coast Railway (LBSCR) and the South Eastern and Chatham Railway; or rebuilt from LBSCR AC multiple units. Some rebuilt units had ‘torpedo style’ front ends, others had the newer, flatter, front ends used on the main-line stock introduced during the early 1930s. They were designated ‘3-Car Suburban Sets’ to differentiate them from main-line units, and were numbered between 1201 and 1800. They are sometimes referred to as ‘3-Sub units’, but this designation does not appear to have been used whilst they were in use.

The 3-car units ultimately proved to be inadequate for most trains and inconvenient as the trailer sets had no driving cabs and so had to be marshaled between two 3-car units. Therefore, many were augmented by the addition of a new trailer car and rebuilt as 4-Sub units between 1942 and 1948. The remainder of the 3-car units were withdrawn. The last 2-car trailer set was withdrawn in September 1948, and the last 3-car formation ran in 1949.

4-Sub Units

In 1939, following the appointment of Oliver Bulleid as Chief Mechanical Engineer, the SR announced a new welded steel 4-car suburban unit with curved sides, seating six passengers across rather than the normal five. The prototype unit, 4101, was not completed until 1941 due to the advent of the Second World War. This had composite (both First Class and Third Class) seating accommodation in one trailer car and domed cab roofs. A further nine units were built in 1944-5 with Third Class accommodation only. Twenty units were introduced from 1946 with a vertical, ‘slab’ front end, and Third Class accommodation only. The underframes were built at Lancing Carriage Works and the bodies at Eastleigh Works.

As mentioned above, between 1942 and 1948 many 3-Car Suburban Sets were rebuilt and enhanced by the addition of a new 'Augmentation' trailer car to create 4-Sub units. This was done by inserting new steel trailers rather than one of the existing trailer cars. The rebuilt units were renumbered between 4131 and 4249.

BR(S) continued to introduce 4-Sub units, both new and converted from existing units, until 1951.

Formations

The usual formation for the newly built units was to have a Driving Motor Brake Third (DMBT) car at each ends, with accommodation for 108 passengers in nine compartments, together with two Trailer Third (TT) cars between with ten or eleven compartments giving a total passenger accommodation for 456 in all four coaches. After the renaming of 'Third Class' to 'Second Class' in 1956 these became DMBS and TS respectively.) However some of the rebuilds had Trailer Composite (TC) cars. The earlier coaches provided compartments, whereas the post war newly built carriages tended to provide saloon or semi-saloon style accommodation to allow for more standing room. These new 'open' carriages were designated DMBTO or TTO.

Operation

Throughout their careers the 4-Sub units were used on the London suburban services of all three divisions of BR (S).

179 out of the 184 new units constructed between 1946 and 1951 were still surviving at the introduction of the TOPS computer system in the early 1970s but were expected to have limited working lives. Under TOPS all surviving units were allocated to Class 405, but divided into two sub-classes. Sub-class 405/1 included the former Southern Railway sets numbered between 4112 and 4387, and sub-class 405/2 included the former British Railways sets built after 1949 and numbered between 4601 and 4754. All had been withdrawn by 1983.

As withdrawals reduced the number of units, services were concentrated in certain areas so that by 1981 units working on the Central section were allocated to Selhurst Depot and were concentrated on to services, and on peak-time commuter services to/from and . Units on the South Western section were allocated to Wimbledon Depot and were concentrated on services between and , or Chessington, although all of the scheduled services were on weekdays.

Withdrawal

The rebuilt units began to be withdrawn in the late 1950s and all had been withdrawn by the end of the 1960s. Apart from a few accident damaged units, the newly built units began to be withdrawn in 1972, and had all been withdrawn by 1983. Those units surviving in the early 1970s were designated as Class 405 under the TOPS computer system.

Departmental use

In 1972 a unit was converted for use transporting stores between Eastleigh Works and various Southern Region depots. Renumbered 024 the unit was based at Slade Green and followed a set route on a weekly schedule serving Stewarts Lane, Ashford, Hither Green, Slade Green and Selhurst.

In 1974 unit 4367 was retired from revenue-earning service and converted for use as a mobile instruction train and was allocated to Ashford Depot. As part of the conversion the unit was renumbered 055.

After withdrawal, some individual steel-bodied trailer vehicles were adapted for use in de-icing the third rail and were fitted with spraying and scraping equipment. These vehicles were renumbered ADS70050/1 and ADS70086/7 and were used in conjunction with stock having Electro-Pneumatic controls. In 1977 some additional conversions for de-icing were made when 6 new 2-car units were created from 4-SUB Motor Brake vehicles. These were renumbered 004 - 009.

Preservation

A handful of Sub stock carriages have survived in preservation, thus:
* Driving Motor car number 8143 (formerly of Sub unit 1293, later 4Sub 4308) is in the care of the National Railway Museum, York.
* 4Sub unit number 4732, formed of DMBTO 12795, TT 10239, TTO 12354 and DMBTO 12796, was retained by British Rail after withdrawal from normal passenger service for use on special occasions. It was stored at the Electric Railway Museum, Warwickshire, after spending many years stored in the open at various locations, but has subsequently been moved to the One:One Collection site in Margate, Kent.4-SUB EMU gets permanent home ''Railways Illustrated'' January 2021 page 25
* Former Departmental Converted 4 Sub Carriage TT 10400 was stored at a private site, but was scrapped around 02/2020.

History of individual units

References

Notes

Sources

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{{British Rail EMU

4SUB
SR 4Sub
Train-related introductions in 1941