Plans for a partial closure of London Bridge Station for nine days in August 2014 have been announced by Network Rail.
The major change to services for nine days between 23 and 31 August 2014 will allow Network Rail to carry out track improvements on the approach to the station and is the first of a number of line closures as part of the rebuilding of London Bridge Station.
During the nine day period no Southern services will call at London Bridge, some First Capital Connect services will be retimed and some Southeastern services may be altered.
A year's notice is being given to allow passengers to prepare or make alternative travel arrangements.
"Rebuilding London Bridge is the biggest engineering challenge taking place on the railway and one of the most important stages of the Thameslink project which will unlock capacity through central London and beyond," said Dave Ward, Network Rail's route managing director for London and the south east.
"We have widely advertised the phased platform closures taking place but we also need a number of shorter, temporary closures to safely carry out extensive track work.
"The alternative to this would be significantly more periods of short closures over many weekends, which would cause much more disruption to passengers.
"We are working closely with the train operating companies and Transport for London to provide information as early as possible and passengers can be reassured that everything is being done to keep disruption to a minimum."
Network Rail has worked with the train companies to plan for line closures to take place over bank holidays and times of the year when passenger numbers are traditionally lower. Underground and bus services will continue to operate as normal throughout the closures.
To publicise the changes to train services to passengers, an exhibition will take place at London Bridge Station during the week starting 2 September.
In a joint statement, train operators First Capital Connect, Southern and Southeastern said: "The September station exhibition is another opportunity for us to talk with passengers about the Thameslink Programme.
"We're working together and with Network Rail and Transport for London to develop alternative travel arrangements for passengers and are committed to sharing this as far in advance as possible.
"The Thameslink website – www.thameslinkprogramme.co.uk – is where passengers can keep up to date with the Thameslink Programme and sign up for email alerts about changes that matter to them."
Another major service change is due to take place between 20 December 2014 and 4 January 2015 when no Southern or First Capital Connect services will call at London Bridge. More details on this, and other blockades, will be announced in due course.
The longer, phased closures which will take place between late 2014 and early 2018 include:
Thameslink route services between Bedford and Brighton through central London will not call at London Bridge.
Southeastern services to and from Charing Cross will not call at London Bridge. Southeastern services to and from Cannon Street will continue to call at London Bridge. Some diversions will take place between Charing Cross, Cannon Street and Blackfriars.
Southeastern Greenwich line, New Cross and St. John's station services are diverted to Cannon Street from January 2015 onwards.
Southeastern services to and from Cannon Street will not call at London Bridge station. Southeastern services to and from Charing Cross will resume calling at London Bridge.