A train bound for London King's Cross from Wearside and through Hartlepool has been cancelled due to overhead power line problems.
Grand Central Trains have said the 15.30 service from the city to the capital.
The company has said its other services between Sunderland and London were also cancelled earlier today due to power line problems between Newcastle and Wearside.
Earlier today, the company said: "Please note that due to problems with lineside equipment affecting the empty stock reaching Sunderland, this morning's 06:45 #Sunderland - Kings Cross will be departing later than usual.
"More information to follow once available from Network Rail."
It went on to cancel services from then onwards.
A spokesman said: "Grand Central apologise for the inconvenience caused by the cancellation of your service today.
"The following arrangements have been made to convey you to your destination.
"Passengers from Sunderland should travel on the 15.31 Northern service towards Hexham, then alight at Newcastle and join the 16.25 Virgin Trains East Coast service to London King's Cross.
"Passengers from Hartlepool will be provided with road transport to Darlington and should then join the 16.57 Virgin Trains East Coast Service to London's King's Cross."