The 24 two car class 456 units were built by BREL York between 1990-91 to provide operational flexibility on the Central Division's suburban services. Like the class 455 and 319s their bodies are based on the Mk3 bodyshell. However a third design of cab front is used similar to that on the class 320/321/322 but with high level jumper cables. As on the 319s GTO thyristor control is used and the class 456 is the last Southern EMU to employ English Electric 507 traction motors. The class can work in multiple with other members of its class and classes 455, 457, 507 and 508.

The units are formed DMSO (driving motor standard open) - DTSO (driving trailer standard open) and they are only gangwayed within the unit. The motor bogie is positioned under inner end of the DMSO. The motor coach seats 79 passengers and the driving trailer 73. The class wore NSE livery from new and were then repainted into Connex SouthCentral livery.

photograph by David Overall

photograph by Michael Taylor

The first delivery (456001) was on 14 December 1990 for commissioning at Strawberry Hill depot. However the class immediately hit a problem. Being designed for driver only operation the driving seat was incorrectly positioned to allow the driver both to observe the platform VDUs through the cab door and to be able to drive in the more forward position. Meanwhile units were arriving from York, being commissioned and then being placed immediately into store not only at Strawberry Hill, which rapidly became full, but also Clapham Yard and Battersea Pier. The solution devised by Selhurst depot was to provide a new driving chair which could slide between the two positions but being interlocked so that traction power could not be applied unless the chair was in the driving position. The new chairs were installed at Fratton depot, though Selhurst, the final home of the class, again had to farm out units for storage until they finally entered service. The fact that such an obvious design fault had been overlooked was an embarrassing episode for Network SouthEast.

The class finally entered service on 30 September 1991 although not on the South London Line until further problems associated with driver only operation had been resolved. 456s were seen working on the South London Line by late 1991/early 1992. In practice the class works as a single unit on lightly used services, and in multiple any permutation of 456s and 455s up to a total of eight cars. Unit 456024 has been named Sir Cosmo Bonsor (with a nameplate on its DTSO) after the late chairman of the SER and also prolific property developer who built many of the suburban housing estates served by Central Division/Connex SouthCentral trains.

photograph by Colin Duff

photograph by Colin Duff