A 15million rail upgrade on the mainline from Norwich to London will cause the weekend cancellation of services via Essex for two months.
Engineering work will start on Saturday, January 31, and Sunday February 1, and continue for eight weekends until Sunday, March 22.
Abellio Greater Anglia will run a bus service while the work takes place.
Network Rail route managing director, Richard Schofield, said: "This investment is absolutely vital to help us deliver a better service for passengers.
We know that people want to travel by train and not a bus, but the line from London Liverpool Street to Norwich carries a huge amount of traffic and desperately needs this boost.
"The project will deliver a more consistent and reliable service for passengers who travel on this line. We would like to thank passengers in advance for bearing with us over these weekends as it will mean some changes to their travel plans."
Work will be carried out at the following locations:
Colchester: More than two kilometres of track will be installed on this 30 years old stretch of the route.
Witham: Network Rail is installing new track and points at Witham. Points allow trains to move from one part of the track to another.
Chelmsford: Engineers continue to upgrade the overhead lines to improve reliability along the Great Eastern Main Line.
Marks Tey: Network Rail is installing new points at Marks Tey, which allows trains to travel from the main line to Sudbury.
Changes
- Main line services will not run between Manningtree and Shenfield.
- Replacement bus services will run between Ipswich, Manningtree, Colchester Town, Colchester and Billericay, where passengers can connect with Southend Victoria services to and from London Liverpool Street.
- Buses will also replace trains between Witham and Braintree, and between Marks Tey and Sudbury.
- A revised train service will operate between Colchester Town and Clacton-on-Sea; Thorpe-le-Soken and Walton-on-Naze; Manningtree and Harwich Town; Manningtree and Ipswich/Norwich.
- Liverpool Street to Southend Victoria services will run to an increased frequency of four trains per hour. Wickford to Southminster services will run hourly.
Greater Anglia managing director Jamie Burles said: "Although there is never a good time for such engineering works, this investment by Network Rail will help in our joint objective to deliver more consistent train service performance on our mainline.
"We will be doing all we can to minimise inconvenience to passengers during the course of these works.
"In addition to Network Rail's investment in the infrastructure, we are also investing over £30m in the current short franchise to improve customer service, train cleaning and rolling stock, including £9m in the project now underway to upgrade our intercity Mark III carriages."
