A train driver and a passenger were taken to hospital with minor injuries after a passenger service from Lincoln was derailed by a mudslide caused by torrential rains.
Some 17 other passengers walked clear of the incident that happened at the exit of the Clarborough Tunnel near Retford in neighbouring Nottinghamshire at midday, today.
The 11.25am local Northern Rail service from Lincoln to Adwick near Doncaster came off the tracks after tons of debris fell onto the line from the steep railway embankment.
Services between Lincoln, Gainsborough Lea Road and Retford were disrupted and the Rail Accident Investigation Bureau are investigating the derailment.
Three appliances from Nottinghamshire Fire and Rescue Service based at Retford were called to the scene, along with four ambulances as the incident was coded critical by the British Transport Police.
"From what we can initially establish, the passenger train came out of the tunnel and run into tons of debris caused by a landslide onto the track," said Inspector Graham Bridges of the BTP."
"Water was pouring down the embankment at the mouth of the tunnel and the front of the train was damaged by the collision."
The driver and one passenger were slightly injured as a result of the derailment and they were taken to the Bassetlaw Hospital at Worksop as a precaution.
The other 17 people who were on the train were all unhurt and taken home by taxi.
Inspector Bridges said that Network Rail faced a major task in restoring services on the line.
"There is literally tons of mud on the tracks and the embankment is still very unstable," he said.
Northern Rail spokesman Joselyn Rankin said: "The 11.25am Lincoln to Adwick service struck debris from a landslide near Clarborough Tunnel between Retford and Gainsborough."
"Early indications suggest that a number of passengers have suffered minor injuries." "Emergency services are on site and are currently dealing with the incident."
"While the damage is assessed, Northern Rail is running road transport between Retford and Lincoln."
For further travel updates please visit www.northernrail.org