British Rail Class 421

Infobox EMU
name = British Rail Class 421


imagesize = 300px
caption = Class 421/7 no. 1498 "Farringford" at Lymington Pier on 26 May 2005. This unit has been restored to 1960s-era British Railways green livery for use on the Lymington Branch Line.
background = #EFF555
Manufacturer = BREL York
Operator = British Rail, South West Trains
Formation = driving trailer + trailer + power car + driving trailer
Built = Unknown
InService = 1964 - Current
Weight = 150 Tons
CarLength = 265ft 8 1/2in
CarWidth = ft 9 in (2.81m)
CarHeight = 12ft 9 1/4in (3.89m)
Capacity =
MaxSpeed = 90mph (145 km/h)
Power = 4 x 250 hp traction motors
total 1,000 hp (746 kW)
Gauge = standard gauge
Voltage = 750V dc third rail

The British Rail Class 421 (or 4Cig) electrical multiple units were built at BR York Works from 1964-1972. Units were built in two batches, and were initially introduced on services on the Brighton Main Line. Later units were introduced on services to Portsmouth. These units replaced older Southern Railway-designed units, such as the 5Bel "Brighton Belle" units, and 4Cor units. These trains were known commonly as "slam-doors".

tandard units

The standard units contained only passenger accommodation, and formed the bulk of the fleet. They were unusual in that all four traction motors were mounted on one non-driving motor coach. Units consisted of two driving trailers, sandwiching an intermediate motor coach, and an intermediate trailer.

Units were built in two batches. 'Phase 1' units were built from 1963-66 for the Brighton Line, and were numbered 7301-7336. These were followed from 1970-72 by the 'Phase 2' units, built primarily for the Portsmouth line, numbered 7337-7438.

4Big units

The 4Big units were similar to the standard units, but contained a buffet car in place of the intermediate trailer.

These units were also built in two batches. 'Phase 1' units were built from 1965-66, and were numbered 7031-48. 'Phase 2' units were built in 1970, and were numbered 7049-7058.

The 4Big fleet were initially classified as Class 420 by British Rail under the new computer numbering system introduced in 1968.

Vehicle numbering

The numbering of individual vehicles and details of when units were built are shown in the table below.

8Dig units

In 1992, four 8Dig units, numbered 2001-2004, were formed by semi-permanently coupling a 4Cig and a 4Big unit. The units were dedicated to London Victoria to Brighton express services, which were operated as the Capital-Coast Express.

The 8Dig units were formed from four 'Phase 2' 4Big units, and two 'Phase 1' and two 'Phase 2' 4Cig units. The 'Phase 1' units, numbers 1901/02 (recently renumbered from 1715/16), were fitted with Mk.6 motor bogies. Interestingly, one of the 'Phase 2' 4Cig units, no. 1875 (ex. 7404), had previously been part of 8Mig unit 2602. Unit formations are listed below:

Fleet details

Original-condition Units
Facelifted units