A number of people were injured and a driver was trapped in his cab when two trains collided in Salisbury.
The incident happened when a wagon was derailed after hitting an object and another train crashed into it when signaling was damaged.
The British Transport Police (BTP) said “a number of people” were injured in the incident at the Fisherton Tunnel near London Road in the city.
All passengers have been evacuated and the injuries are believed to be minor, and PA news agency sources describe them as “walking injured”.
The driver, who was trapped after the accident, has been released from his cab and driven to the hospital – but is not seriously injured, sources confirm.
Emergency services, including about 50 firefighters, attended Sunday night with a critical incident that was declared.
A Network Rail spokesman said: “Around 7pm tonight, the rear carriage of the 1708 Great Western Railway service derailed from Portsmouth Harbor to Bristol Temple Meads after hitting an object as it approached Salisbury station.
‘The derailment knocked out all signaling in the area. Subsequently, the 1720 South Western Railway service from London Waterloo to Honiton collided with the Bristol train. “
The derailed train was thought to be on the side, but the South Western Railway train is standing upright.
BTP said a casualty center has been set up at St Mark’s Church, on St Mark’s Avenue in the city.
Transport Minister Grant Shapps tweeted: “My thoughts go out to those affected by the serious railway incident near Salisbury.”
He said the Rail Accident Investigation Branch and the Office of Rail and Road would investigate it, adding: “We need to understand how this happened to prevent in the future.”
A mother who was out tricking or treating with her family nearby compared the noise from the crash to “a bomb” and “thunder.”
Tamar Vellacott said she went outside with her young children, mother and partner at Jewell Close, Bishopdown, about a mile from the site.
“It was a noise we’ve never heard before … my young people started to panic and think it was a bomb and we said a truck might have crashed on London Road and not to go in. panic, “said the 25-year-old PA.
“There was no scream like brakes, just a long rumble like thunder hitting the railroad line.”
A spokesman for the Office of Rail and Road said: “We support Network Rail and the train operators, plus RAIB (Rail Accident Investigation Branch) and the UK Transport Police regarding the collision between two trains near Salisbury Tunnel Junction and emergency response services. the incident. “
The Secretary General of the Transport Salaried Staffs Association, Manuel Cortes, said the incident was “a very sober reminder of why the safety of our railways is always paramount”.