An elderly woman on a mobility scooter crashed through train doors and onto the track after boarding a Metro service on South Tyneside.
The scooter hit with enough force to break the door's lock open
She drove onto the train at Brockley Whins station with enough force to break open the opposite door's lock, according to Metro operator Nexus.
A spokesman said no door had ever been forced open on Tyne and Wear Metro and called the incident "unprecedented".
The woman suffered bruising but was not seriously hurt.
An investigation into the incident, on Monday morning, has been launched, but the initial findings indicate that there was no fault with the train door.
Nexus spokesman Huw Lewis said: "The speed at which the mobility scooter was travelling is subject to the investigation, but it was driven with enough force to crash through the doors.
"The scooter didn't actually drop onto the tracks but became wedged in the open doors, and the woman then fell out.
"A passenger on the opposite platform jumped down and partially broke her fall."
It is the first time Nexus has seen a door forced open, and there was no risk that trains were unsafe, he added.
"We've had incidents of vandals kicking doors and damaging locks and in those cases the trains have been taken out of service.
"But in 27 years of operating the Metro, no door has ever been forced open. It's unprecedented."