The first types of the 1963 design BR(S) EMUs to be introduced were the 4 Cigs and their buffet equivalents the 4 Bigs. The first batch were assigned to the Brighton line which gave the units their designation - IG was the LBSCR telegraphic code for Brighton. Early units introduced in 1 964/5 were painted BR(S) green with small yellow panels, the only 1963 design stock to be so. This generation of stock was built to the later Mk1 body design, and as an innovation to SR EMUs the two driving cars were unpowered (driving trailer composites - DTCs) and the formation includes an intermediate non-driving motor brake coach (non driving motor brake second saloon - MBSO) with two power bogies. The fourth car in the formation is a trailer second saloon (TSO) in the Cigs and a trailer buffet second (TBUF) in the Bigs. As these units were designed for main line service they are fitted with 2+2 low density seating in second/standard class.

The second batch was introduced in 1970 to replace 4 Cors on the Portsmouth Direct line. These and the later batch had detail differences to the 1964/5 batch. A third batch was introduced in 1971/72 to replace 4 Cors on Reading and Central Division services. Cigs and Bigs have never been allocated to the South Eastern Division.

In 1983, in order to provide sufficient catering stock whilst Big buffets were being overhauled, two temporary 8 Mig formations, sets 2601 and 2602, were put together as 4 Cig+RMB+3 Cig - note the use of a wired locomotive hauled catering car. Then to introduce the "Capital Coast Express" service for the summer 1993 timetable (prior to 319s becoming available) four 8 Dig formations (units 2001-4) were put together. These were semi-permanently coupled 4 Cig+4 Big sets. The Big was at the London end with the motor coaches as second and seventh in the formation. Inner set numbers were painted out but full yellow ends were retained within the sets and driving controls in the inner cabs were retained. The Digs were disbanded in January 1997.

Although the early part of the service life of these classes was unaffected by significant changes and refurbishment the past few years have been much different. Some 4 Big units have been converted to 4 Cig by withdrawing their buffet cars and substituting TSOLs from 4 Cep units downgraded to 3 Ceps. The difference in the window design between the refurbished Cep car and the original Cig/Big cars is very noticeable. Other 4 Bigs have been converted to 3 Cops ("corridor open-plan") by removing the buffet car and 1st class seating in the driving trailers. Compartment partitions were removed but the side corridor is retained and as a result the DTC is redesignated to DTSOL. One toilet is converted to a store in each DTSOL and a wheelchair seating compartment is installed in the former cage area of the brake van. These Cop units (originally classified class 424/3, but by 1999, class 421/7) were first used on Connex South Central coastway services (although they also strayed to London services on occasions) on 17 November 1997 and the full fleet was in service by February 1998. The improved acceleration is found to be an asset on these services. From mid 1998 CSC started the downgrading of 1st class accommodation in one DTC to DTSOL (as with the Cops), and by spring 1999 a wide yellow stripe on the roof was being added to identify the remaining 1st accommodation.

photograph by Paul Ferbrache

photograph by Paul Ferbrache

photograph by Jonathan Hall

photograph by Jonathan Hall