Work has started to build a passing loop which will enable future hourly services to run between Ipswich and Lowestoft.
Currently, train services between Ipswich and Lowestoft run every two hours.
There is a single track between Halesworth and Oulton Broad, meaning that trains cannot pass each other for more than 16 miles.
The £4m scheme, jointly funded by Network Rail and Suffolk County Council, will bring a disused platform back into use at Beccles station and track and signalling works will also be carried out in October, as part of a wider £21m project to resignal the East Suffolk Line, to improve reliability and performance.
Dave Ward, Network Rail route managing director, said:
“This investment will make a huge difference to people living in the area and is part of our wider plans to build a bigger and better railway.
“Enabling more services will mean that people living along the East Suffolk Line will be better connected to the main line.
“We are investing around £1bn across the Anglia route to run a better and more reliable train service for passengers.”
