The British Rail Class 302 (pre-TOPS AM2) was a type of electric multiple unit (EMU) introduced between 1958 and 1960 for outer suburban passenger services on the London, Tilbury and Southend line. This class of multiple unit was constructed using the Mark 1 bodyshell and was slam-door.
Overview
Like all the Eastern Region AC EMUs of the period, they were equipped to operate on both 25 kV AC and the reduced 6.25 kV voltage in the inner London areas where headroom for the overhead wires was reduced. On the LT&S the changeover point was just east of Barking station on both Upminster and Tilbury routes with the link to Forest Gate being at 6.25kV ac.
Each unit was formed of four coaches, in the following formation: DTSOL (Driving Trailer Second Open with Lavatory) – MBS (Motor Brake Second) – TCsoL (Trailer Composite semi-open with Lavatory) – DTS (Driving Trailer Second). The initial set numbers were 201–312, later prefixed by the class number 302 with the introduction of TOPS.
The Battery Driving Trailer and Driving Trailer were fitted with drop head buckeye couplers with screw coupler in the Guards Van, retractable buffers are also fitted only on outer ends of the Battery Driving Trailer/Driving Trailer.
Service history
Public service started on 16 March 1959 with Class 302s working the first electric passenger trains between Colchester and Clacton at 25kV ac. A revised half hourly timetable started on April 13 from Colchester with a 8 car train splitting at Thorpe-le-Soken with half going to Walton-on-Naze
Some Class 302s were used for crew training in Manchester before the Class 304 units were introduced in April 1960.
They were among the first electric units delivered to the Eastern Region and, although ordered for the LT&S electrification, a route they were long associated with, they were used initially on the Liverpool Street to Hertford East, Bishop's Stortford and Enfield Town lines when they were electrified in November 1960. The 302s also stepped in when electrification was extended from Chelmsford to Colchester in 1961 and when the Class 305 units were having problems on the then new north-east London electric services. Some formations were temporarily reduced to three cars for the Enfield Town services.
The first 25 units remained on the GE main line for the bulk of their lives, with the remainder operating on the LT&S from Fenchurch Street from 1962.
Between November 1961 and June 1962, the class suffered traction motor insulation trouble which meant the motors had to be re-wound.
302312 was used as a test bed for silicon rectifier technology and a Brentford transformer from 1962 to 1964, then used to test thyristor control equipment until 1972, becoming the first electric train so fitted in the UK.
Unit 302 244 was involved in an accident in 1972 with a lorry at a level crossing at Low Street railway station in Tilbury, after which it was decided to scrap the leading carriage, BDTC 75292. This was replaced with DTSO 77164, originally belonging to a Manchester-Bury Line Class 504. It remained like this until May 1983 when it acquired a spare BDTC, 75298, from withdrawn unit 302250.
In 1987–88, 6 units were short formed with the removal of the trailer composite (TCsoL) and based at Ilford EMD for work on the GE lines.
Following the privatisation of British Rail, ownership of the last 30 units passed to Eversholt Rail Group with all units being leased by LTS Rail.
The run-down of class 302s started in 1984 with the majority being phased out when Class 310 were introduced on to the LT&S in 1988 with last 30 units being withdrawn by 1998 with the introduction of Class 317 in 1997 and with extra Class 312 in 1998.
Electrical equipment
Electrical equipment was supplied by English Electric with the majority of equipment being interchangeable with Class 308 units.
Electrically there were three main systems, Control which operated at 110 volts DC, provided by nickel iron alkaline secondary cells, auxiliary 250 volts AC from the tertiary winding of the main transformer which provided power to the battery charger which was also rectified to power the main compressor, and finally power circuits derived from secondary winding of the main transformer at 1,500 volts AC.