Rail passengers will face nine consecutive days of disruption with the suspension of trains from Norwich to Great Yarmouth and Lowestoft.
Greater Anglia will not operate its regular services between Saturday, March 23 and Sunday, March 31, to allow the continuation of improvement works on the Wherry lines.
Rail replacement buses will operate as an alternative before the lines reopen on Monday, April 1.
Trains between Oulton Broad South and Lowestoft will not run for seven days until Friday, March 29, meaning services from Ipswich will terminate at Oulton Board South with rail replacement provided from Beccles.
Jamie Burles, Greater Anglia's managing director, said: 'We apologise for the inconvenience caused while these works take place. However, we would like to reassure customers that they can still complete their journeys by bus.
'This work is essential for the transformation of the railway in East Anglia. Both Network Rail and Greater Anglia are investing in the region, and new trains are due to come into service later this year.'
This latest work forms part of a wider Network Rail project, as engineers upgrade Victorian era signalling systems and track - some of the oldest in the country.
Passengers who travel between Reedham and Great Yarmouth have already been inconvenienced since October last year as a new track layout is installed at Reedham junction.
Next month's improvements will focus on major track remodelling at Brundall junction, as well as reconfiguration of the junction, construction of a new access ramp at Brundall station and the reconstruction of 50 metres of platform to accommodate new trains.
Meliha Duymaz, Network Rail's route managing director for Anglia, added: 'We're continuing to deliver necessary upgrades to bring the Wherry lines into the 21st Century.
'The modern signalling systems will help to increase safety and reliability of the railway. I'd like to thank passengers for their continued patience while we upgrade these systems for the benefit of everyone.'
Engineers will complete testing of the new signal controls before announcing a date for them to come into operation. A date for the reopening of the Reedham to Great Yarmouth line will also be announced in due course.
Rail replacement bus information can be accessed by visiting the Greater Anglia and National Rail websites.
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