Those hoping for a late Christmas getaway are being warned to travel earlier by Great Western Railway.
Planned engineering work means no trains will run between London Paddington and Reading on Sunday, December 24, and Wednesday, December 27.
Reservations for trains towards Devon and Cornwall on Friday, December 22 and Saturday, December 23, are already almost sold out.
No trains will operate to or from London Paddington station on Sunday, December 24 and Wednesday, December 27, as Network Rail begins work on the new HS2 station at Old Oak Common.
Services are not scheduled to operate on Christmas Day or Boxing Day.
Most GWR services start or terminate at Reading instead of London Paddington.
Limited GWR and Elizabeth line train services will run between Reading and Ealing Broadway
Connecting Underground services will run from Ealing Broadway into central London
If you need to travel on December 24 or December 27, allow plenty of time to reach your destination as journey times will be significantly longer than normal.
Service will also finish earlier than usual on Sunday, December 24, and all journeys will need to be completed by approximately 2230.
Customers looking to travel on either of these days should consider travelling on alternative dates for a more comfortable journey.
Dean Haynes, GWR’s station manager for London Paddington, said: “As we continue to invest in our railway, we will only be able to run trains to and from Reading and Ealing Broadway on December 24 and 27.
“To keep you moving, we have been working with other train companies to provide alternative routes.
“However, if you can travel on the days before or after, you should consider doing so because journeys will take much longer while the work takes place.”
Joanna Grew, Network Rail’s industry programme director, added: “Over the Christmas period, we will be carrying out essential preparatory drainage and railway infrastructure works as part of the construction of HS2’s new station at Old Oak Common near London Paddington.
“We appreciate there is never a good time to disrupt journeys but whenever possible we do this at times when fewer people are travelling, such as at Christmas, on bank holidays or at weekends.
“We thank passengers in advance for their patience and urge them to please check before they travel.”
Customers travelling to or from central London can do so using London Underground’s District or Central line services at Ealing Broadway. The Elizabeth line will not operate between Ealing Broadway and London Paddington.
Alternatively, GWR tickets can be used with South Western Railway between Reading and London Waterloo, or on Chiltern Railways between Oxford and London Marylebone.
No Heathrow Express services will run during this time. Customers travelling to Heathrow Airport from central London should use the Piccadilly line instead.
For the latest information, visit GWR.com/Christmas.