East Coast Main Line train delays due to overhead lines
Thousands of rail passengers are facing delays on the East Coast Main Line because of continuing problems with overhead lines.
Services have been disrupted between Peterborough, Cambridge and London King's Cross due to problems between Stevenage and Hitchin in Hertfordshire.
Earlier this morning no services ran between Hitchin and Stevenage.
The line between Welwyn Garden City and Letchworth for London to Cambridge services may remain shut all day.
But Network Rail says the line between Welwyn Garden City and Biggleswade has reopened, enabling trains to run between London and Peterborough.
Greater Anglia have put on extra services between Cambridge and London.
Earlier, the East Coast problem meant that a main London to Scotland route suffered major delays.
Passengers are advised to contact National Rail Inquiries or follow the hashtag #Hitchin on Twitter.
The continuing problem, which had led to hours-long delays to evening rush-hour commuters on Monday, is affecting passengers with four train companies - East Coast, First Capital Connect, First Hull Trains and Grand Central.
The problem involved 14 "droppers", which are part of the overhead wires and which were found to be broken with contact wires damaged, causing damage to trains.
An East Coast spokesman said: "We apologise to passengers for the continued disruption to East Coast services this morning. Trains are now starting to move again through the affected area near Hitchin.
"A half-hourly East Coast service is now operating from London King's Cross and we expect services to progressively resume throughout the day.
"Earlier this morning, another train operator's service joining the main line at Hitchin was involved in an incident which led to reports of new overhead power line damage, following damage yesterday afternoon.
"Network Rail - which is responsible for track, signals and overhead lines - tell us that further damage to the overhead power lines was found at just before 07.00 this morning.
"Road replacement services are operating between Peterborough and Bedford; and we have been operating a shuttle service between Peterborough and Cambridge using a diesel train.
"All ticket restrictions have been lifted and East Coast tickets are being accepted by other operators on alternative routes."