London: Passengers were thrown from their seats and dragged along the floor when a train derailed on a major line south of London, trapping some in carriages that were tipped to their sides.

Many passengers climbed out of the carriages and walked to safety from the wreckage of the train after it left the tracks during its journey from Victoria Station in London to the seaside town of Eastbourne.

But 11 passengers were injured, two of them seriously, the British Transport Police declared after paramedics assessed patients at the scene before taking them to hospital.

One passenger told the BBC he was on the train, which had about 150 people aboard, when he felt it “sliding” over the tracks.

“We just went over and we were dragging along the floor,” said Charlie Hobden, 31, from Lewes, a town close to the scene of the accident.

“We tried to open the doors and then we saw people standing on top of the train and so we managed to get out on our own. Others waited and got on ladders to get out.

“Then the emergency serves helped us out and got we got assessed.” Hobden did not have any injuries and returned home.

Another passenger, Rob Bradley, said the train began rocking as it picked up speed and the carriage he was riding in with his 6-year-old daughter jumped upward and the brakes immediately engaged.

“Everything got thrown forward. My laptop, my AirPods, our bags,” Bradley told the BBC.

“The train kind of skidded for quite a while before it stopped and only then when we turned around did we see that the whole back of the train – literally where we were sat – was open and there was smoke and dust pouring into the carriage.”

Bradley said he could then see the car behind had flipped on its side and slid down an embankment into a lower field.

He said he and his daughter were uninjured, but he could see other passengers from one of the flipped cars with blood on their heads and clothing. Another passenger told him they had been cut when a window shattered.

Photographs from the scene showed three carriages were lying on their side in a field alongside the railway line, while several other carriages were still on the tracks.

Aerial footage showed firefighters and paramedics treating passengers in a field next to the train, with several ambulances and three helicopters standing by.

The cause of the derailment is under investigation, although some experts suggested the heat wave sweeping Europe may have played a role.

William Powrie, a professor of geotechnical engineering at the University of Southampton, told London’s Telegraph that continuously welded rails could buckle if they were unable to expand in hot weather, and the hard, dry ground could also cause track deformities

“Therefore, this incident could be hot weather related, but the exact causal chain of events needs to be established through proper and thorough investigation,” Powrie said.

British Transport Police declared a major incident.

“Our thoughts are of course with everyone affected, and I’d like to reassure the public that we’re supporting the rail accident investigation branch to establish exactly what’s happened,” BTC Assistant Chief Constable Ian Drummond-Smith said.

With AP

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David Crowe is Europe correspondent for The Sydney Morning Herald and The Age.Connect via X or email.