Transport secretary Justine Greening has announced a £350 million plan to extend platforms at London Waterloo Station.
The proposal forms part of the "High Level Output Specification" programme for 2014-2019 published by the Department for Transport on Monday.
The platform lengthening project is part of a package of measures to create extra capacity for commuters into London by running longer trains.
The DfT estimates that the number of passengers arriving at Waterloo during the three busiest hours of the morning rush hour is likely to increase by nearly 10 per cent over the next five years.
No further details of which lines will benefit from the longer trains have been published.
Nor is there any mention in Monday's announcement of the future use of the former Waterloo International terminal.
The international terminal's owners, BRB Residuary, last month embarked on a programme to clean and repaint the roof of the Nicholas Grimshaw-designed station that will last until next spring.
One of the five platforms underneath that roof, platform 20, is due to be used by domestic trains from 2014 but no timetable has been set for the reuse of the rest of the building.