A Metro train had to be pulled out of service due to large amounts of graffiti.
The train was withdrawn on Tuesday morning and some services had to be cancelled after two thirds of the train had been damaged by vandalism, Nexus confirmed.
This affected early morning services between Pelaw, Monkseaton and South Gosforth.
There are also delays of 15 minutes on trains running between South Gosforth and the Airport "due to an earlier train fault and this train being changed over". Passengers are being advised to leave extra time for their journeys.
A Nexus spokesman said: "This was due to graffiti. It was taken out of service due to the amount of graffiti.
"This was for safety reasons for those who need disabled access as the graffiti would have affected the visibilty."
