It also emerged last night that quick action by the express train's driver had averted a disaster.
A four-carriage local train, operated by the First North Western company, was standing on the "fast line" used by express services when it was hit at 8.52am by a Virgin West Coast train, 300 yards south of Winsford station in Cheshire.
Railtrack said the Virgin train, with 132 people on board, should have had a clear passage along the line.
"We will look into all potential causes," said a joint statement from the three firms. "This includes ... the report that a North Western train passed a red signal." The findings of the investigation will be passed to the Health and Safety Executive inquiry team.
The Virgin train was travelling at up to 110mph when its driver, Roy Eccles, saw the local train ahead. In the seconds before impact, Mr Eccles, 56, applied emergency brakes and managed to release on to the track sand that is normally used to provide extra grip in icy conditions. Friction between the wheels and the track bought him vital extra braking power.
As a result, only his own carriage on the express was derailed, coming to rest - windows shattered - amid the local train's mangled rear coach.
Mr Eccles, who has 35 years' experience, jumped down from his cabin, hurting his leg, and, after ensuring that his conductor and crew were tending to passengers, walked down the track to apply clips which short- circuit the signals and turn them red.
One passenger, a soldier, Pte Lee Topliss, 21, who had just flown back from Kosovo, said the train had slowed to about 50mph when it crashed. He said: "My ribs were sore, but I jumped off the train to see if the driver was OK. I found him checking the carriages."
At first, paramedics were unable to remove casualties from the train because the power to the electrified line had not been switched off.
Some passengers climbed down to safety on ladders raised by fire crews; ambulance helicopters carried injured passengers to hospital. A total of 16 men and 15 women attended the Crewe hospital's accident and emergency department with the youngest casualty aged 20 and the eldest 85. Five were detained overnight.
Some people suffered abdominal injuries after the force of the collision thrust them into tables. Others had whiplash neck injuries and scalds from hot drinks. No one was seriously hurt.Reuse content