A major section of the East Coast Main Line is to close over the August bank holiday weekend as part of its £1.2bn upgrade.
No trains will run between Peterborough and London stations to allow for new tracks, signals and engineering work.
The line is being upgraded to accommodate the new LNER Azuma trains, which came into service last month.
Network Rail said the number of tracks on the line into King's Cross will eventually increase from four to six.
The East Coast Main Line runs for 393 miles (632km) between London and Edinburgh, via stations including Peterborough, Doncaster, York and Newcastle.
The government took over the service in June 2018 from joint franchise holders Stagecoach and Virgin.
It is the first time in 20 years that the Peterborough to London stretch will completely shut down for improvements.
It will close during 24 and 25 August, and a reduced service will also be in place on 13 and 14 July to allow old equipment to be removed from a disused tunnel - and new track laid.
Passengers are being advised to plan their journeys ahead of the disruption.
Rob McIntosh, route managing director for Network Rail, said the upgrade promises up to 10,000 extra seats, faster journeys and improved reliability.
"We're doing everything we can to keep disruption to a minimum, but passengers will need to plan ahead and check before they travel," he said.
"Once completed, this upgrade will improve journeys and ensure we can continue to provide a service which meets the needs of the passengers, communities and economies we serve."
Source: BBC