A rush-hour train derailed in Liverpool tunnel on Wednesday evening, local police said, adding that there were no immediate reports of injuries.
"We do have a derailment and we have approximately 90 passengers on board. We are leading them off and there are no reports of injuries so far," a spokesman for the Merseyside fire service said.
A spokeswoman for the Merseyside Ambulance Service also said they had not received any reports of injuries.
Local media said the train had derailed inside a tunnel, reports Reuters.
All passengers were led to safety within two hours and there were no major injuries, transport police said.
The aftermath is causing a major disruption to commuters with no service from Hunts Cross to Southport on Thursday morning.
Two elderly people had to be treated at the scene for shock but did not need hospital treatment.
Helen King, assistant chief constable of Merseyside police, said: "The majority of people were removed from the train by walking down the track.
"We are glad to say everyone is safe and well."
She said the train would be examined by experts including the Rail Accident Investigation Unit.
"All the indications suggest this was caused by some kind of mechanical failure, there is nothing to indicate any type of criminal attack, we want to reassure people of that."
Passengers on the train told the BBC how the carriages "juddered" and the lights went out.
A passenger, who gave her name as Mary, said: "The train just started going crazy, informs BBC.