8Mig units

In 1983, two temporary 8Mig units, given the TOPS classification Class 482 and numbered 2601–2602,^[2] were formed while the 4Big fleet underwent asbestos removal. They were used on the Portsmouth Direct line. Therefore, four standard 'Phase 2' 4Cig units, numbers 7401–7404, were reformed with a conventional locomotive-hauled miniature buffet carriage (RMB). Each 8Mig unit was formed by marshalling the RMB coach in between two units, one of which was reduced to three carriages, with the removal of the intermediate trailer (TSO). Thus in effect each 8Mig unit was effectively formed of 4Cig + RMB + 3Cig. The formations of the units are listed below:

These units were only used during the summer of 1983, after which enough asbestos-free 4Big units were available. The two 8Mig units were disbanded and the four 4Cig unit reformed. The 4Cig units have since been renumbered several times, as shown 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 plus 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. One of the 'Phase 2' 4Cig units, no. 1875 (ex. 7404), had previously been part of 8Mig unit 2602. Unit formations are listed below:

The units were disbanded in 1996, after replacement by dedicated Class 319/2 units. The various 4Cig and 4Big units were reformed and gained their original numbers, except unit 1875, which was renumbered to 1802.

Class 421/4, no. 1879, at Charing Cross on 18 March 2003, with a service to Hastings. This unit was operated by South Eastern Trains, and is painted in Network SouthEast livery. This unit has since been withdrawn from traffic and scrapped.

South Eastern Trains

South Eastern Trains (SET) operated a small fleet of three 'Phase 1' and 22 'Phase 2' 4Cig units. The franchise was originally operated by Connex South Eastern.

All but one of the 'Phase 2' units continued to carry the obsolete Network SouthEast livery. One unit, no. 1870, was repainted into Connex South Eastern yellow and white. The three 'Phase 1' units were painted in white undercoat livery, since their use was originally only supposed to be short-term. However, despite this, the units remained in traffic for seven more years, from 1997 to 2004. They were popularly known as "Ghosts" by rail enthusiasts.

From 2003 units started to be withdrawn, having been replaced by the second batch of the new "Electrostar" units. The three 'Phase 1' units had gone by mid-2004. The final unit, no. 1843, lingered on for several months longer than its classmates, eventually being withdrawn in mid-November 2004. All the SET units have been scrapped.

South Central / Southern

Class 421/8, no. 1396, at Clapham Junction on 19 July 2003. This unit is one of eight "Greyhound" units converted from redundant 4Big units for use by South West Trains. The buffet coach was replaced with a spare 4Cep trailer vehicle, which is identifiable by its different windows as the second vehicle in the unit.

The South Central Division inherited the largest fleet of 4Cig units. Originally this included all remaining 'Phase 1' units (though some were later transferred to South Eastern Trains), 35 'Phase 2' units, and the four 8Dig units. The remaining few 4Big units were also used on the former Central Division.

The South Central franchise was initially won by Connex South Central, which applied its yellow and white livery to most stock. In 2000 it lost the franchise to the Go-Ahead Group, which operated the franchise as South Central. In 2004 this was changed to Southern. Four 'Phase 1' units (nos. 1735/38/40, 1908) and eight 'Phase 2' units (nos. 1854/56-62) received Southern's new green livery.

In 1997 the remaining 4Big units were withdrawn. Eight were transferred to South West Trains. The remaining eleven unit were heavily rebuilt at Eastleigh Works, with compartments removed and opened out, and the buffet carriages withdrawn. The modified units were reclassified as Class 421/7 and renumbered into the 1401–1411 range. The units were also known as 3Cop units, which denoted their intended use, i.e. dedicated to East Coastway and West Coastway services out of Brighton. Two units received names – a rarity for slam-door EMU stock.

• 1408 - Littlehampton Progress 2000
• 1409 - Operation Perseus

In 2004 some units were augmented to four carriages with the addition of a 'Phase 1' intermediate trailer, and thus became 4Cop units.

From 2003 Southern started to replace its slam-door fleet with new Class 377 Electrostar units. In general the 'Phase 1' units were withdrawn first due to their age, but as deliveries of the Electrostars increased some 'Phase 2' units were also taken out of service. By late 2004 only a handful of 'Phase 1' units and 4Cops remained in service. The final 'Phase 1' units in traffic were nos. 1704/08/11/12/14/17/43 and 1901, with the final unit, no. 1704, being withdrawn in February 2005. The final 4Cop units, nos. 1404/10/11, were withdrawn in March 2005.

The 'Phase 2' units lasted longer and two, nos. 1805 and 1866, were retained beyond August 2005, when slam-door trains lost all diagrammed work. They lasted until 19 November 2005, when they worked a farewell railtour, following which they were withdrawn.

South West Trains

4Cig in 1980 in Guildford

The last day of operation on the Lymington Branch Line

South West Trains inherited a small fleet of twelve 'Phase 2' 4Cig units, and the larger fleet of 22 "Greyhound" units which had been modified to cut several minutes from journey times on the Portsmouth Direct line with its 1 in 80 gradients by adding a second stage of field weakening to improve performance at higher speeds (17% at 54 mph, 30% at 90 mph).

In 1997 the fleet was augmented with the addition of eight 4Big units from Connex South Central. These operated with the counter in the buffet carriages locked out of use. By 1999 these units had been stored, but then eight additional "Greyhound" units were converted from the redundant 4Bigs. The units were reclassified as Class 421/8, and renumbered in the range 1392–1399. The modifications included the removal of the buffet carriages, which were replaced by spare intermediate trailers from mechanically similar 4Cep units. Most of these trailers came from 4Cep units to make 3Cep units, but a few came from withdrawn units. These trailers were immediately recognisable since although they had the same body profile as the rest of the unit the windows were different and they had InterCity70 seating. The buffet carriages were withdrawn, although many were saved for preservation.

In December 2004 unit no. 1394 was reduced to a three-car unit with the removal of its Cep trailer. It was reclassified as Class 421/7, renumbered 1499, and dedicated to the Lymington Branch Line service, where it replaced the previous incumbent unit, no. 1198.

Withdrawals of units started in mid-2004, when many new Class 444 and Class 450 "Desiro" units became available for service. By the end of 2004 just a handful of units remained in traffic. The final few units were withdrawn in May 2005, with the last in traffic being 1304/09/12/16, 1392/95/96/97/98, 1499 and 1881/90. The final slam-door service ran on 26 May from London Waterloo to Bournemouth using units 1396, 1398 and 4Vep 3536. Following withdrawal two units, nos. 1304 and 1881, were transferred to "warm storage" for use by Southern if required. Most of the other units were sent for scrap, with the exception of nos. 1392 and 1499.

Services on the Lymington Branch Line were operated as a "heritage" operation using one of two refurbished 3Cig units, nos. 1497 and 1498. The two units were launched into service on 12 May 2005 having been repainted into heritage liveries, 1497 in blue and grey and 1498 in the green that the units carried when built. However, in May 2010, the new timetable changes saw the units replaced for more modern stock to save maintenance on a non-standard fleet of two units. As stated in the relevant timetable, "The slam door trains will be remembered with affection as they pass into history." The change took place on 22 May 2010 and the units have been replaced by a Class 158 on weekdays and a Class 450 Desiro at weekends. The class 421s have both been preserved due to historic significance.