Trains between London Victoria, Clapham Junction and Balham are to be disrupted over the whole of the Christmas and New Year period as £160m engineering works take place.
The scheduled improvements to track and signalling equipment is to happen next weekend (October 29-30) as well as the weekend of November 26-27.
Over the Christmas period, there will be no services running between Victoria and East Croydon from Christmas Day until January 3, with passengers advised to reroute their journeys via London Bridge or Blackfriars.
Gatwick Express services will also be affected on the above dates, with Southern stating that further dates will be added as and when they are confirmed.
Network Rail senior project manager Kristine Harris said: “Over the past two years, we’ve been working around the clock to modernise the signalling system in the Clapham and Balham area.
“This Christmas, our teams will be testing and bringing the new signalling system into use ahead of commuters returning in January.
“We know there is never a good time to close the railway but by working for ten consecutive days over the holidays when lines are significantly quieter, means we can get the work completed more quickly and reopen the railway lines on time.”
The works are part of a two-year project to update 1980s track and signalling on the railway and help to improve the reliability and efficiency of all trains. Engineers will be working at Clapham Junction station to change the track layout.
115 new ticket gates are to be installed at Victoria station to improve the throughput of passengers and reduce queues to get through to platforms.
Below are the weekends affected by the works:
Saturday October 15 to Sunday October 16
Saturday October 29 to Sunday October 30
Saturday November 26 to Sunday November 27