Greater Anglia is warning customers may face disruption ahead of upcoming industrial action.
Alterations to services are set to take place until Sunday, December 9, owing to strike actions.
A reduced timetable will be in operation on some days, while on others there will no trains at all.
The rail company has confirmed services on two lines will be cancelled due to action called by ASLEF.
People will be unable to travelling between Ipswich and Felixstowe, as well as Sudbury and Marks Tey, due to the action.
There will also be a reduced service between Norwich and London Liverpool Street due to strikes, while no services will be running on other lines.
Customers are advised to check before they travel.
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