Up to a dozen passengers are believed to have been injured after a crash involving two trains in Salisbury, England.
The incident happened when a train was derailed after hitting an object, and a second train then collided with it when signalling was affected.
The driver trapped after the crash has been released from his cab and has been taken to hospital, but is not seriously injured.
Emergency services are at the site close to London Road in Salisbury.
British Transport Police said a casualty centre has been set up at St Mark's Church in the area.
Sources told the PA news agency that up to a dozen passengers are believed to have been injured, describing them as "walking wounded".
We are currently responding to an incident at Fisherton Tunnel, Salisbury. Officers were called at 6.46pm this evening following reports a train derailed.— British Transport Police (@BTP) October 31, 2021
We are on scene alongside paramedics and the fire brigade. Further updates will be shared here. pic.twitter.com/oUGY0VttRh
A Network Rail spokesperson said: "At around 7pm this evening, the rear carriage of the 1708 Great Western Railway service from Portsmouth Harbour to Bristol Temple Meads derailed after striking an object on its approach to Salisbury station.
"The derailment knocked out all of the signalling in the area.
"Subsequently, the 1720 South Western Railway service from London Waterloo to Honiton then collided with the Bristol train.
"There are reports of injuries and the emergency services are on site along with railway first responders."
The derailed train is believed to be on its side, but the SWR train is upright.
A critical incident has been declared and the line will remain closed at the country end of Salisbury.
All passengers have been evacuated and injuries are believed to be minor.