As part of the Thameslink Programme a replacement of rolling stock will take place.
The Class 319 have been in service since 1987. They have served the Thameslink route ever since apart from 13 units which were in service with (Connex South Central) now Southern. All Class 319 trains were transferred to Thameslink services to increase capacity.
These units are dual-powered, from either 25 kV alternating current (AC) overhead lines (for services north of London), or 750 V direct current (DC) third rail (to the south).
Class 319 trains can be found on the following routes:
Bedford to Brighton via Gatwick Airport
St Albans to Sutton via Hackbridge (Sutton Loop)
Luton to Sutton via Wimbledon (Sutton Loop)
West Hampstead to Sevenoaks via Catford
The withdrawal of these trains have started, up to 9 units have already been transferred to Northern Rail for use on newly electrified lines in the Liverpool area.
The Thameslink fleet now comprises of the following rolling stocks:
These batches of trains will be in use until the brand new, purpose built Class 700 trains are introduced.