Since 1997 the measure to address capacity issues on the Brighton Main Line has been to introduce new rolling stock for the Southern franchise. The old slam door fleet has been fully replaced, with 24 per cent. extra trains in total, with each new train having more capacity than the train it replaced.
The next phase of capacity enhancement will be implemented as the Brighton Main Line Rail Utilisation Strategy (BML RUS). The BML RUS will make better use of the existing capacity on the Brighton Main Line. After this the next measure would be the Thameslink programme that will be decided on as part of the comprehensive spending review this year
The High Level Output Statement (HLOS), again due to be published this year, will set out the best long-term plan to accommodate the growth on this route beyond the steps already taken and the plans already in place.