Network Rail says journeys between Ipswich, Lowestoft and Felixstowe will be smoother and more reliable following the installation of 15km of new track.
Around 15,000 metres of new rail and 10,150 sleepers were replaced as part of Network Rail's railway upgrade plan.
The line was closed between Ipswich and Halesworth from July 29 to August 6 while the work took place.
16,500 tonnes of ballast were also replaced to improve drainage and reliability. A grid was installed at Westerfield station to keep the ballast in place and the tracks aligned, which they say will make for a smoother journey and further improving reliability.
Simon Ancona, Network Rail's chief operating officer for Anglia, said: 'New track is less susceptible to damage, meaning fewer delays and disruption caused by damage to the track. I'd like to thank everyone for their patience while we carried out the work.'
Jamie Burles, managing director of Greater Anglia, added: 'This new track will help us to run a more reliable, on-time railway and make customers' journeys better. We would like to thank our customers for their patience and understanding while this work was carried out.'
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