Panic-stricken passengers were thrown from their seats and hit by falling luggage after a high speed train came to an emergency stop.
The driver of the 8.20am from Newcastle to King's Cross hit the brake near Peterborough on Sunday.
One passenger told the Mirror: "It was a nightmare. There were passengers screaming. It felt like the train was going to derail."
The train was then delayed by an hour and a half.
Neuma Domingos had a panic attack and hurt her leg and train operator Lumo has apologised for any distress caused.
Police said 15 people had minor injuries and the Rail Accident Investigation Branch had been informed.
Operator Lumo confirmed all travellers had been rerouted and the train was taken out of service for safety checks. Two services were cancelled as a result.
Ms Domingos, a student at King's College, London, said: "Everything was fine until very abruptly we started veering to the right. All things fell on the floor. I was leaning on to the woman next to me and she almost fell out of her seat. And then very rapidly the train swung from side to side, heavily on to the left side all the luggage fell at this point.
"I hit my knee, people were gasping, a couple of people cried out - it was like really bad turbulence on a plane."
Billie Rainer, 25, was left "shaken". "The train was swinging from side to side as it went around the corner very fast," she told the BBC.
"I felt like a massive jolt and I was lifted out of my seat. I wasn't injured but other people were, by falling items. A woman was limping because she'd been hurt. It did feel like the train had approached the corner way too fast. It was so much worse than plane turbulence."
Ellie Foster, 24, of Canterbury, Kent, tweeted a picture of her dented suitcase after it fell from a shelf.
British Transport Police (BTP)received a report of an emergency stop at 11.53 am. Officers met the train at King's Cross and talked to passengers who were offered medical assistance by paramedics at the station, a spokesman said.
Lumo runs trains on the East Coast Main Line between London King's Cross and Edinburgh Waverley.
All Lumo trains on the service are electric. The operator was "very sorry for any distress the sudden stop may have caused".
A spokesman added: "Such events can be jolting for passengers and we took great care to check on everybody's welfare.
"There was some falling luggage and naturally many people will have felt the effects of the sudden halt."
It added: "A full investigation is now under way and we are supporting our driver and the Rail Accident Investigations Branch to determine precisely what happened."
All passengers were entitled to a full refund.
