SANTIAGO DE COMPOSTELA, JULY 26: The driver of a Spanish train that derailed, killing at least 80 people, was under police guard in hospital on Thursday after the dramatic accident which an official source said was caused by excessive speed. 

The eight-carriage train came off the tracks, hit a wall and caught fire just outside the pilgrimage destination Santiago de Compostela in northwestern Spain on Wednesday night. It was one of Europe's worst rail disasters. 

The source had knowledge of the official investigation into a crash which brought misery to Santiago on Thursday, the day when it should have celebrated one of Europe's biggest Christian festivals. Authorities cancelled festivities as the city went into mourning. 

The Galicia regional supreme court said in a statement the judge investigating the accident had ordered police to take a statement from the driver. 

He was being formally investigated and under police guard but not under arrest, the court said. He was in hospital but it was not clear what kind of injuries he had suffered. 

Video footage from a security camera showed the train, with 247 people on board, hurtling into a concrete wall at the side of the track as carriages jack-knifed and the engine overturned. 

One local official described the aftermath of the crash as like a scene from hell, with bodies strewn next to the tracks. 

The impact was so huge one carriage flew several metres into the air and landed on the other side of a high concrete barrier. 

Around 94 people were injured, 35 of them, including four children, in a serious condition, the deputy head of the regional government said. 

"We heard a massive noise and we went down the tracks. I helped get a few injured and bodies out of the train. I went into one of the cars but I'd rather not tell you what I saw there," Ricardo Martinez, a 47-year old baker from Santiago de Compostela, told Reuters. 

Newspaper accounts cited witnesses as saying the driver, Francisco Jose Garzon, who had helped rescue victims, shouted into a phone: "I've derailed! What do I do?". 

The 52-year-old had been a train driver for 30 years, said a spokeswoman for Renfe, the state train company. 

A court source told Reuters there was one driver on the train. Previously, a Galicia governmentsource had said there were two.