Rail passengers are being advised to travel earlier to avoid disruption over the Christmas period, with more than 200 sets of engineering works planned.
Routes across London, Kent, East Sussex, Lancashire, Essex and Glasgow are among the lines to be shut.
Network Rail, which controls the UK’s railways, says 95% of the network will be unaffected and it is the least disruptive time to do this work.
Bus replacements are planned but journey times are likely to increase.
London Paddington will be closed for four days between Christmas Eve and 27 December with Great Western Railway advising passengers to travel by 23 December “at the latest”.
Between 23 December and 1 January, there will be no Greater Anglia trains between London Liverpool Street and Ingatestone or Billericay.
Elsewhere, buses will replace trains between Preston and Lancaster from Christmas Eve until 27 December.
Over this three-day period, those travelling between London and Glasgow will also face longer journey times as passengers are advised to go via Edinburgh.
Southeastern trains will not be running to London Bridge, Charing Cross or Cannon Street from 23 December to 1 January.
Network Rail’s chief executive Mark Carne said most of the network is open for “business as usual” but some routes will be “heavily affected”.
He strongly advised passengers to plan ahead this Christmas.
“We know that our railway is up to 50% quieter than usual during the festive period, so taking on and delivering these huge transformational schemes at this time of year minimises our impact on passengers.”