Buses will replace trains this weekend (Saturday March 6 and Sunday March 7) and again over the weekend of Saturday March 20 and Sunday March 21, and impact journeys between Broxbourne, Stansted Airport and Audley End.
Work to replace tracks is being carried out on the West Anglia Main Line between Liverpool Street, Stansted and Cambridge.
Tracks need to be replaced to avoid faults that cause delays and cancellations.
Just over two miles of track will be replaced between Stansted and Broxbourne along with 120 tonnes of ballast - the stones that keep the track in place - and 2,280 tonnes of sleepers over the weekend of Saturday March 6 and Sunday March 7.
Over the weekend of Saturday 20 and Sunday 21 March, 180 tonnes of ballast and 2,880 tonnes of sleepers will be replaced.
Network Rail’s engineers will be using the high output track relaying system train to replace existing rails and sleepers with high-performing new ones.
It works like a conveyor belt, the front part of the train runs on the old rails, while the rear runs on the new rail that the system has installed.
The rail replacement bus while the work is being done will affect passengers travelling between Broxbourne, Stansted Airport and Audley End.
Ellie Burrows, Network Rail’s route director for Anglia, said: “This work is essential to keep services running safely and reliably for our passengers on the West Anglia main line.
"Track wears faster on the busy main lines and replacing it will reduce the number of delays and cancellations caused by track issues.”
Jamie Burles, Greater Anglia managing director, said: “This important work will help improve punctuality and reliability on our busy West Anglia route.
“We would like to thank customers for their patience while this work is carried out.
“Government advice is currently to stay at home and only travel for legally permissible reasons such as work or medical appointments.
"We will make sure you can travel safely, both on the train and rail replacement bus.
"Everyone should wear a face covering while travelling with us for their entire journey, unless they are exempt.”
Passengers are advised to check before they travel at www.nationalrail.co.uk or with their train operator.
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