Train services between Norwich and Cambridge are facing delays today, due to signalling problems.
Buses have replaced trains between Thetford and Norwich until further notice, according to Network Rail.
Greater Anglia said the problem was due to an 'external electricity supply problem' which had meant the signalling system had been lost between Thetford and Norwich.
The train operator said UK Power Networks was working on that issue, while Network Rail engineers were working to provide an emergency power supply.
It follows a day of disruption on the railways yesterday, with passengers on the Norwich to London train line after suffering delays because of problems with overhead power lines.
That was a problem with overhead power lines at Needham Market at about 10.45am yesterday, which meant Network Rail engineers spent much of the day working to fix the problem.
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 The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.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