Commuters from Brighton and Hove were given a reminder yesterday (Tuesday 24 November) about the engineering works planned for Christmas and the new year.
Network Rail said that vital work at Purley meant that passengers could expect diversions, longer journeys and more crowded trains.
Some journeys will involve replacement buses taking passengers between Three Bridges and East Grinstead.
Network Rail, which owns the track and infrastructure, said: “Improvement work on the Brighton mainline may affect your journey this Christmas.
“From close of service on Christmas Eve 2015 to (Sunday) 3 January 2016, Network Rail is undertaking vital work at a major junction in Purley.
“The work involves essential track renewals, bridge repairs and the replacement of signalling and power equipment in the area.
“The work at Purley will mean significant changes to Southern, Thameslink and Gatwick Express services.
“Trains will continue to run and you will still be able to travel to and from London and Gatwick but journeys may be diverted, could take longer and trains may be busier.
“Southern services will also close down early on Christmas Eve, so please check before you travel.
“Normal train services will resume early on the morning of (Monday) 4 January 2016.”
Network Rail added: “If you are travelling from Brighton or coastal stations to Gatwick Airport, trains are running but please check your train times before you travel.
“If you are travelling from Brighton to London Victoria you will be able to travel to Three Bridges for a connecting bus to East Grinstead where you will need to board a train to complete your journey.
“This journey will take between two and two and a half hours.
“Your journey will be affected and you may need to find an alternative route. Tickets will be accepted on reasonable alternative routes, not including High Speed 1.
“Please check before you travel at southernrailway.com/christmas2015.”
There will be changes to many trains across Britain as part of Network Rail’s railway upgrade plan.
For example, the Thameslink programme is continuing to rebuild the railway around London Bridge.
This work will mean major changes to Southeastern services, including no trains at London Bridge, Cannon Street, Charing Cross or Waterloo East from 8pm on Christmas Eve through to Sunday 3 January 2016.
There will also be work taking place on Transport for London services so please check before you travel at tfl.gov.uk//festive.
