Lines into London Euston will be restricted on December 27 and January 3 before engineers then close the West Coast Main Line between Milton Keynes and Rugby for eight days to upgrade flood protection.
London Northwestern Railway says it will operate a Saturday service from December 28 to January 3 with buses replacing some late-night trains between Milton Keynes and Northampton until New Year's Eve.
NHS consultant ordered to demolish part of his massive house in Milton Keynes submits plans to make it even BIGGER
Iconic building comes tumbling down in Milton Keynes town
Appeal to help find missing teenage boy from Milton Keynes area
Appeal following fatal collision on M1 at Milton Keynes
M1 closed southbound at Milton Keynes following serious collision involving van and crane
All trains, including those run by Avanti West Coast, will be diverted via Northampton from January 4, reducing the number of trains able to run to and from Euston until work on a four-kilometre stretch of track is completed January 12.
London Northwestern Railway passengers travelling between Northampton and the Midlands and North West will need to change trains at Rugby.
Avanti West Coast passengers face an extra 25 minutes added to journey times between Milton Keynes and Rugby.
Lawrence Bowman, customer experience director for London Northwestern Railway, said: “These essential maintenance projects over Christmas and New Year will improve the reliability of our rail infrastructure and reduce the likelihood of delays in the future.
"I urge customers to plan their rail travel in advance during the West Coast Main Line work near Milton Keynes in January when some journeys will take longer.”
Services will finish early on December 24 while no trains will run anywhere in the UK on Christmas Day with very limited services on Boxing Day.
James Dean, Network Rail’s West Coast South route director, added: “We’ve worked hard with train operators to reduce the impact of our railway upgrade work on passengers so that they can spend time with their families and friends this Christmas and New Year.
“We do have major work approaching in January which we’re letting people know about early on — so it doesn’t come as a surprise. Fortunately, we can use a diversionary route so passengers can stay on the move, albeit with slightly longer journeys or the need to change trains.”