Two people were injured when a train carrying about 50 passengers crashed through the buffers at a station.
is at the end of a line connected to the station liverpool street Making it popular with commuters working in the City of London.
Rory O’Neill, transportation to the General Manager of London London Overground described the incident as a “low-speed collision”, and added that “there will be a full investigation to establish how this happened”.
More than a dozen emergency service vehicles were deployed at the scene.
London Fire Brigade station commander Jim O’Neill said around 50 people were evacuated from the train, which went “over the top” of the buffers.
A spokesman for the British Transport Police said the driver and another person were “examined by paramedics”.
She said the driver’s breathing was “regular”, and had a “negative blow”.
Network Rail said the driver was treated for shock.
The London Ambulance Service said two people were assessed at the scene for minor injuries, but were not taken to hospital.
An employee at a nearby postal sorting office said he was “shocked” at the sight of the crashed train.
Gary Spencer, 37, told the PA news agency: “(Initially) there was some shock but, more importantly, (I was hoping) there were no casualties.”
He continued: “I never knew that a train would fail to stop at the end of the line … if the metal had not been behind the steel buffer I believe the train would have damaged the building.”
Rail regulator Rail and Road Office said it sent two safety inspectors to the crash site “to help establish the full circumstances surrounding the incident”.