Passengers heading from Essex to London by train at weekends have been advised to check before they travel as the main line will be closed at Chelmsford.
Network Rail is building a new station just north of the Essex city and the line will be closed on most Sundays between now and the beginning of November.
This weekend the line is closed on Saturday as well - but after that the closures are on Sundays only.
Buses will take passengers from Witham to Ingatestone from where they can continue their journey to London.
However on September 29 there are more extensive engineering works and passengers will be taken by bus from Witham to Newbury Park Tube Station on the Central Line.
Full details of all the closures can be found on Greater Anglia's website.
Lawrence Bowman, Network Rail’s route director for Anglia, said: "We've worked hard with Greater Anglia to minimise weekend disruption, however Christmas will be a crucial time to bring the new rail systems into use and we need these autumn dates to make sure we deliver for this critical milestone."
The current list of closures runs until Sunday November 3, but more closures may be announced for late autumn.
And in recent years there have regularly been line closures during the period between Christmas and the New Year to allow engineers more time to complete complex projects.
Jamie Burles, Greater Anglia managing director, said: “Work is well underway to build the new Beaulieu Park railway station, which will hugely benefit people in Essex.
“A rail replacement service will run while these works take place, and passengers are advised to check before they travel and allow more time for their journey this autumn.
“We would like to thank customers for their patience and understanding while this work is carried out.”
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