Someone has been hit by a train between Durham and Newcastle.
All lines are blocked and it is currently not clear when they will reopen.
National Rail Enquiries said it anticipated trains would be disrupted until at least 19:30.
Trains aren't running between Darlington and Newcastle but some services are being diverted via Sunderland, not calling at stations via Durham.
Operators are trying to arrange buses between Darlington and Newcastle.
Trains may be delayed by up to 60 minutes or be cancelled altogether.