There were no trains running on large parts of the network this morning after a power cut.
There were no trains running between Heworth and the Airport, meaning passengers from Sunderland and South Shields cannot travel to stations in Newcastle or the North Tyneside.
Go North East buses were accepting Metro tickets.
Nexus has now announced trains are running again, but with delays while services return to normal.
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Chris Carson, Metro Services director, said: “We suffered a major power failure just after 6am this morning which meant we couldn’t run trains through South Gosforth and Newcastle city centre to Heworth or Airport.
"Engineers worked as fast as they could to fix the problem and trains were running to all stations from 9am. I know this caused a great deal of inconvenience to our passengers and I want to say sorry to anyone who was held up this morning.
"We were able to run trains through Sunderland and to and from Chichester in South Shields; we also kept trains going to and from Newcastle city centre via North Shields and Whitley Bay.
"We set up Metro ticket acceptance on local buses across the area as soon as we could, though the number of people travelling meant there were long queues at interchanges like Heworth. We sent extra staff to key stations to provide information and advice to passengers.
"We have now recovered the service and trains will be frequent, though not to timetable, through the morning. We expect a normal service during this evening’s peak period.”