Metro services were hit by delays last night after a police incident involving an 'aggressive' passenger.
Trains were delayed by up to 30 minutes system wide at around 6pm on Wednesday night after police were called to deal with a man acting aggressively on the Metro.
Northumbria Police have confirmed that the man suffered minor injuries to his head after passengers intervened.
No one else is believed to have been injured.
The man was then ejected from the carriage at Gateshead Station and received treatment for minor injuries.
Police have now launched an appeal for information and are asking people to contact them by calling 101.
A force spokesperson said: "At about 5.33pm yesterday (Wednesday) we received a complaint about a male acting aggressively on the Metro.
"Other passengers intervened and as a result the male suffered minor injuries to his head.
"He was later ejected from the carriage at Gateshead Station.
"No one else is believed to have been injured.
"Officers and emergency services attended and he received treatment for minor injuries.
"Anyone with information about this incident is asked to contact police by calling 101 quoting reference 795 170419."