Some rail services to and from Ipswich and Clacton are being altered due to signalling problems.
Trains are instead starting and finishing at Colchester.
Some services are also being cancelled, while others are starting at Shenfield instead of at London Liverpool Street.
Rail operator Abellio Greater Anglia has apologised for the disruption.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here