The service is suspended on Greater Anglia between Ipswich and Felixstowe due to a broken down train at Trimley.
There is no estimate for when a normal service will resume.
Abellio, who run the Greater Anglia rail line, has been named Train Operator of the Year at the annual national Rail Business Awards.
Greater Anglia train operator Abellio says it's made real steps in customer service and punctuality in its first year in charge.
Greater Anglia have apologised for the delays that have disrupted services today