A replacement bus service is running on First Capital Connect between Hitchin and Royston due to emergency engineering works.
Journey times may be extended by up to 30 minutes. There is no estimate for a normal service.
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