Rail passengers across the region will soon be able to trfavel on longer trains and a new direct service to Stansted.
Improvements on the Fen Line between King's Lynn and Cambridge, which will allow longer trains to run, will begin over the weekend of October 5 and 6.
Platforms at Littleport and Waterbeach are being extended and a new siding built in King's Lynn to accommodate longer services.
Network Rail Anglia said there would be some weekend disruption to passengers travelling between King's Lynn and Cambridge while the work was in progress.
Route director Mark Budden said: "I am sorry for the weekend disruption to services. When complete, it will bring much needed relief on overcrowded peak services between King's Lynn and Cambridge, improving the journey experience for passengers."
Network Rail has also apologised to people living around Exton's Place in Lynn for any disruption while the siding is being built.
Elsewhere, Greater Anglia said a new direct service between Norwich and Stansted Airport would be launched on December 15, giving people in the city a direct rail link to the airport for the first time.
Seven services will operate in each direction Mondays to Fridays, with 15 on Saturdays and 13 on Sundays.
Trains will also run hourly on Sundays between Ipswich and Cambridge, Ipswich and Lowestoft and Norwich and Lowestoft.
Services between London Liverpool Street and Cambridge are also to be extended to Cambridge North seven days a week.
Greater Anglia said it would be running 37 additional services per week from the start of the new winter timetable, delivering around 9,000 extra seats per week.
Martin Moran, Greater Anglia's commercial and customer service director, said: "These improvements are helping us to transform the railway for the people of East Anglia as we continue the introduction of our brand-new fleet of trains into passenger service."
The dates when passengers between Lynn and Cambridge could face disruption are every Saturday and Sunday between October 5 and December 1, except for October 19 and 20.
Other dates affected include Christmas Day, Boxing Day, February 1 and 2, 22 and 23, 2020, and Easter weekend April 10-12, 2020.
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