British Rail Class 421

The British Rail Class 421 (4CIG) electric multiple units were built at BR's Holgate Road carriage works between 1964 and 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. The fleet's lifespan was 46 years.

British Rail Class 421 (4CIG)
Class 421/7 No. 1498 at North Weald in 2012
The interior of Standard Class aboard a Class 421
In service	1964 - 2005 (Mainline services) - 2010 (Lymington branch)
Manufacturer	Holgate Road carriage works
Number built	166 (138 class 421 (4 CIG) and 28 class 422 (4 BIG) Units)
Formation	Driving trailer + Motor coach + Trailer/Buffet + Driving trailer
Operators	British Rail South West Trains Connex South Central Connex South Eastern Network SouthEast Southern South Eastern Trains
Specifications
Train length	265 feet 8+1⁄2 inches (80.988 m)
Width	9 feet 3 inches (2.82 m)
Height	12 ft 9+1⁄4 in (3.893 m)
Maximum speed	90 mph (145 km/h)
Weight	150 long tons (152 t; 168 short tons)
Traction motors	Four
Power output	4 x 250 hp (190 kW) total 1,000 hp (750 kW)
Electric system(s)	750 V DC third rail
Current collector(s)	Contact shoe
Coupling system	Drop-head buckeye
Track gauge	4 ft 8+1⁄2 in (1,435 mm) standard gauge

The interior of a First Class compartment aboard a Class 421

Class 421/5, no. 1313, at London Waterloo on 19 July 2003. This is one of 22 "Greyhound" units that were operated by South West Trains.

Standard 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 the non-driving motor coach and an intermediate trailer.

Units were built in two batches. 'Phase 1' units were built from 1963 to 1966 for the Brighton Line, and were numbered 7301-7336. These were followed in 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 in 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 TOPS system introduced in 1968, and then Class 422.

Vehicle numbering

Class 421/6 no. 1908 at London Victoria on 15 August 2004. This unit was one of eight modified 'Phase 1' unit fitted with Mk.6 motor bogies. It was also one of only four 'Phase 1' units to be repainted in South Central livery.

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

Phase	Type	Unit nos.	Years built	DTCsoL	MBSO	TSO (*TRSB)	DTCsoL
Phase 1	4Cig	7301–7336	1964–65	76076–76111	62017–62052	70695–70730	76022–76057
	4Big	7031–7048	1964–65	76112–76129	62053–62070	69301–69318*	76058–76075
Phase 2	4Cig	7337-7366	1970	76581–76610	62287–62316	70967–70996	76611–76640
		7367–7437	1970–72	76717–76787	62355–62425	71035–71105	76788–76858
		7438	1972	76859	62430	71106	76860
	4Big	7049-7058	1970	76561–76570	62277–62286	69330–69339*	76571–76580

Refurbishment

Units were facelifted between 1986 and 1993.

8Mig units

In 1983, two temporary 8Mig units, given the TOPS classification Class 482 and numbered 2601–2602, 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:

8Mig unit No.	4Cig unit					RMB coach	3Cig unit
	Unit no.	DTCsoL	MBSO	TSO	DTCsoL		Unit no.	DTCsoL	MBSO	DTCsoL
2601	7401	76751	62389	71069	76822	1872	7402	76752	62390	76823
2602	7403	76753	62391	71071	76804	1873	7404	76754	62392	76825

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:

Unrefurbished		Facelifted
74xx series	12xx series	18xx series	8Dig unit	18xx series
7401	1201	1868	-	-
7402	1202	1860	-	-
7403	1203	1869	-	-
7404	1204	1875	2001	1802

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:

8Dig unit no.	4Cig unit					4Big unit
	Unit no.	DTCsoL	MBSO	TSO	DTCsoL	Unit no.	DTCsoL	MBSO	TSRB	DTCsoL
2001	1875	76754	62417	71072	76850	2262	76779	62392	69333	76825
2002	1902	76100	62041	71768	76046	2254	76732	62379	69306	76803
2003	1801	76777	62415	71095	76848	2255	76740	62378	69310	76811
2004	1901	76082	62023	70701	76028	2259	76748	62386	69318	76819

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.

Final years of operation

Two units had remained in service until 22 May 2010, 3Cig units nos. 1497 and 1498, which were used on the Lymington Branch Line. These two units were withdrawn from service on 22 May 2010 and replaced by Class 158 Diesel Multiple Units. Towards the end of their life, with the increasing use of newer trains which were equipped with sliding or plug doors, these trains were known commonly as "slam-door trains". 1497 is now preserved at The Mid Norfolk Railway and 1498 is now preserved on the Epping Ongar Railway. The latter has had an extra carriage added to restore its original 4Cig formation.

Privatisation to withdrawal

After rail privatisation in the mid-1990s the different divisions of British Rail were divided up into different franchises. The three former SR division – South-Eastern, South Central and South-Western – all operated 4Cig units, and are dealt with separately here.

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 421/4 1860 in Connex South Central livery at St Denys

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

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 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.

Accidents and incidents

Phase 2 4CIG 7346 after running away at Wimbledon in 1974

• On 15 December 1971, a Cardiff to Portsmouth Harbour train hauled by Hymek diesel no. D7013 collided with unit 7303 on the high level section of Portsmouth and Southsea station, Hampshire. Sixteen passengers and railway staff were injured
• In summer 1974 (date unknown) unit 7346 ran away at Wimbledon Park and hit a flyover causing extensive damage to the cab of vehicle 76620.
• On 26 January 1985, unit 7395 formed a train with 4VEP units 7754 and 7703 which was halted by a landslip near Popham, Hampshire and was run into by Class 33 locomotive 33 104 due to the train crew failing to protect the stranded train. Twelve people were injured and the Class 33 was written off.
• On 6 November 1985, unit 7390 collided with 4VEP unit 7724 at Copyhold Junction, near Haywards Heath, West Sussex due to poor rail conditions and a loss of braking. Forty people were injured.
• On 4 March 1989, unit Nos. 1280 and 1295 formed a passenger train that overran a signal and collided with another passenger train formed of 4VEP unit 3441 at Purley, Surrey. Five people were killed, 8 were injured.
• On 6 April 1989, unit 1822 was derailed at Wimbledon whilst working a London Waterloo to Southampton service. There were no injuries.
• On 1 August 1990, Class 119 diesel multiple unit L576 collided with a passenger train comprising 4VEP units 3508 & 3504, and 4CIG unit 1304 at Reading due to overrunning signals. Forty people were injured.
• On 29 August 1990, unit 1221 was derailed at Ash Vale Junction whilst operating a Guildford to Ascot service.

Further use

Following withdrawal from normal service several vehicles have seen further use in departmental service.

• 3Cop unit 1401 was employed as depot shunter at Ashford Chart Leacon depot. However, it was made redundant when Chart Leacon stopped overhauls of slam-door stock and was sent for scrap in July 2005.
• MBS 62356 (ex-unit 1850) was converted into an ultrasonic test train vehicle for use by Network Rail. It has been renumbered 999606.
• The rest of unit 1850, namely DTC 76629, TS 71036 and DTC 76789, were retained by Network Rail to provide spares for 999606 but have now been scrapped by C.F. Booth in Rotherham.
• One vehicle, no. 76112 from 'Phase 1' 4Cig unit 1749, was rebuilt as the Class 424 "Networker Classic" prototype in 1997. It was displayed to the public at London Victoria, paired with unrebuilt driving trailer 76747 from 4Big unit 2256, for comparison purposes. The project was shelved and the vehicle was scrapped in early 2012.
• DTCSoL vehicles 76765 and 76836 (from 1882) plus 76775 and 76846 (from 1890) were released recently by HSBC from Shoeburyness for parts stripping at Derby RTC, after which they went to C.F. Booth.

Preservation

Only two units have been preserved in addition numerous buffet cars from 4Big units have also been preserved. The full list is shown below, with complete units highlighted:

• 'Phase 1' unit 1753 has been preserved by the Network SouthEast Railway Society and is stored at Nemesis Rail, Burton Upon Trent.
• 'Phase 2' unit 1497 is preserved on the Spa Valley Railway.

Former preserved CIGs include:

• 'Phase 2' unit 1304, Scrapped by the Brighton Belle Preservation Trust.
• 'Phase 2' "Greyhound" unit 1392, scrapped by the Brighton Belle Preservation Trust. (MBSO in extremely stripped condition survives as a shell)
• 'Phase 2' "Greyhound" unit 1393, scrapped by the Great Central Railway, MBSO in use with Network Rail.
• 'Phase 2' "Greyhound" unit 1399, partially component recovered by owner in 2016 to provide spares float for "4-VOP" Unit 3905 and other projects. Unit was used in filming of 'Last Passenger'
• 'Phase 2' unit 1498, exported to Ireland for use as 'Glamping' accommodation.
• 'Phase 2' unit 1499, Scrapped by the Dean Forest Railway.
• 'Phase 2' unit 1881, Scrapped by the Brighton Belle Preservation Trust. (One DTS remains at Barrow Hill)
• 'Phase 2' unit 1884, Scrapped by the Brighton Belle Preservation Trust

No Greyhound Units survive. No 8MIG or 8DIG units survive.

Preserved units

Unit Number (current in bold)					Type	Phase	DTCsoL	MBSO	TSO (*TSRB)	DTCsoL	Livery	Location	Notes
7032	2101	2251	-	-	4Big	Phase 1	-	-	69302*	-	Network SouthEast	Abbey View Disabled Centre	-
7034	2110	2260	-	-	4Big	Phase 1	-	-	69304*	-	South West Trains	Northamptonshire Ironstone Railway Trust	stripped out
7036	2104	2254	2002	-	4Big	Phase 1	-	-	69306*	-	BR(S) Green	Spa Valley Railway	Used as a static café as Tunbridge Wells West station.
7040	2105	2255	2003	-	4Big	Phase 1	-	-	69310*	-	BR(S) Green	Dartmoor Railway	-
7046	2108	2258	-	-	4Big	Phase 1	-	-	69316*	-	BR(S) Green	Riccarton Junction	Waverley Route heritage centre.
7048	2109	2259	2004	-	4Big	Phase 1	-	-	69318*	-	BR(S) Green	Mid Norfolk Railway	-
7051	2203	-	-	-	4Big	Phase 2	-	-	69332*	-	BR(S) Green	Swanage Railway	To be used as part of 4TC set,based at Swanage.
7054	2206	-	-	-	4Big	Phase 2	-	-	69338*	-	Yellow and Green	Bahrain	Exported to Bahrain
7053	2205	-	-	-	4Big	Phase 2	-	-	69339*	-	BR(S) Green	Nemesis Rail - Burton on Trent, with 1753	-
7055	2207	2112	2262	2001	4Big	Phase 2	-	-	69333*	-	BR(S) Green	Lavender Line	-
7057	2209	-	-	-	4Big	Phase 2	-	-	69335*	-	LNER Green/Cream	Wensleydale Railway	-
7058	2210	-	-	-	4Big	Phase 2	-	-	69337*	-	BR Green	Hastings Diesels	Operates with preserved Class 201 unit 1001.
7327	1127	1753	-	-	4Cig	Phase 1	76102	62043	70721	76048	Connex	Finmere until January 2020	Privately owned by Mr N D Bird, supported by the Network SouthEast Railway Society and named 'Chris Green' after the managing director of Network Southeast. Undergoing restoration work at Nemesis Rail, Burton-on-Trent.
7373	-	1819	1306	-	4Cig	Phase 2	-	-	71041	-	Green	Hever railway station
7337	-	-	-	-	4Cig	Phase 2	-	62287	-	-	Network rail research livery	Derby	Now in Network Rail service as an ultrasonic test coach.
7376	1276	2251	1394	1499	4Cig	Phase 2	-	62364	-	-	South West Trains	Barrow Hill Engine Shed
7396	1295	2258	1393	-	4Cig	Phase 2	-	62384	-	-	Network rail research livery	Derby	Now in Network Rail service as an ultrasonic test coach.
7397	1297	2256	1399	-	4Cig	Phase 2	76747	-	-	-	BR Green	East Kent Railway (heritage)
7397	1297	2256	1399	-	4Cig	Phase 2	-	62385	-	-	South West Trains	East Kent Railway (heritage)
7412	1212	1881	-	-	3Cig	Phase 2	76762	-	-	-		Barrow Hill Engine Shed
7414	1214	1883	1497	-	4Cig	Phase 2	76764	62402	-	76835	BR Blue/Grey	Spa Valley Railway	Formerly on the Lymington Branch Line. And is now preserved at the Spa Valley Railway and is once again is carrying passengers on selected days
7417	1217	1884	-	-	4Cig	Phase 2	-	-	71085	-	White / Art Design	Morden Wharf, Greenwich	Now out of use, in store.
7423	1223	1888	1498	-	3Cig	Phase 2	76773	62411	-	76844	BR Green	County Sligo, Ireland	Formerly on the Lymington Branch Line. In use on the Epping Ongar Railway until mid 2013. Now Sold for use at Camping site in Ireland

Fleet details

Original-condition Units

Class	Type	No. built (Converted*)	Year built (Converted*)	No. range	Withdrawn	Notes
Class 420	4Big	18	1965-66	7031-7048	1986	Facelifted 1985-86, and renumbered as Class 422 units 2101-2112.
		10	1970	7049-7058	1988	Facelifted 1986-88, and renumbered as Class 422 units 2201-2210.
Class 421	4Cig	36	1963-66	7301-7336 (later 1101-1136)	1993	Facelifted 1986-1993, and renumbered into 17xx range.
		102	1970-74	7337-7438 (later 1201-1300)	1993	Facelifted 1987-1993, and renumbered into 18xx and 13xx range.
Class 421	8Mig	2*	1983*	2601–2602	1983	Converted back to standard 4Cig.

Facelifted units

Class	Type	No. Converted	Year Converted	No. range	Operator	Units nos.	Withdrawn	No. preserved
Class 421/3	4Cig	53	1986-93	1701–1754	SET	1701/42/48	06/2004	1
					Southern	1702-14/17/19-22/24-27/31/33-48/50-54	02/2005
Class 421/4	4Cig	87	1987-93	1801–1826 1831-1891	SET	1806-1813/39-43/70-73/75-79	11/2004	-
					Southern	1801-1805/31-35/37/45-48/50/51/53-69/74	11/2005
					SWT	1880-1891	05/2005
Class 421/5	4Cig	22	1990-92	1301–1322	SWT	1301-1322	05/2005	-
Class 421/6	4Cig	8	1994	1901–1908	Southern	1901-1908	01/2005	-
Class 421/7	3Cop	11	1997	1401–1411	Southern	1401-1411	03/2005	-
	3Cig	3	2004-05	1497–1499	SWT	1497-1499	05/2010	2
Class 421/8	4Cig	8	1999	1392–1399	SWT	1392-1399	05/2005	-
Class 422/0	8Dig	4	1992	2001–2004	South Central	2001-2004	1996	-
Class 422/1	4Big	10	1985-86	2101–2112	BR	2101-2112	1989	-
Class 422/2	4Big	10	1986-88	2201–2210	South Central	2203-06/8-10	1997	-
Class 422/3	4Big	12	1989	2251–2262	South Central	2251-62	1997	-
					SWT	2251/54-56/58/59/61/62	1999	-

Diagrams

Further reading

• Marsden, Colin J. (1982). EMUs. Motive Power Recognition. Vol. 2. Ian Allan. pp. 92–97. ISBN 9780711011656. OCLC 16537600.