38-year-old Gary Rogers and his daughter caught the Metro at Longbenton at 12.35 today.
While they were in the tunnel between Monument and Central station, there was a massive flash, a bang and the train ground to a halt.
An hour and a half later they were rescued by the fire brigade.
The train driver had said he couldn't let them out for safety reasons.
While they were still aboard the train it was very dim, although the emergency lighting kicked in after a couple of minutes.
Gary says there were at least a dozen children on the train, including a woman with a baby. He describes it as being quite hot underground.
Staff were giving people water. Gary's ten year old daughter described it as 'being a good adventure today'.
Watch: footage of their rescue