Passengers travelling to and from London Waterloo are being asked to plan ahead for major changes to the station next year.
The work, which is part of an £800 million upgrade to the station and railway, will take place between August 5-28 2017.
Platforms 1-9 will be closed during that time.
Upgrades will include bringing the five platforms of the former international terminal back into use, extending platforms 1-4 to accommodate 10 car trains and introducing 10 car trains between Waterloo and Reading.
Network Rail route managing director Stuart Kistruck said: ‘During this period we will be closing platforms 1-9, so services will use the other existing platforms as well as platforms 20-24, which will re-open during August’s changes.
‘As there will be major impacts on services, we want everyone to have plenty of time to plan ahead while we invest for better journeys down the line.’
South West Trains managing director Christian Roth said: ‘The Waterloo and South West Upgrade is the biggest investment in this railway for decades and will provide more trains, more seats and more space for tens of thousands of passengers every day.’
The two companies have started handing out information leaflets and travel card holders to passengers with information about the changes.
Timetables and more detailed travel advice will be published early next year.