Investigations into Spain's worst rail disaster in more than 40 years – which has left at least 80 people dead and more than 160 injured – are focusing on the driver after officials confirmed that excessive speed caused the train to career off the rails.
The train broke up and slammed into a wall as it rounded a bend near Santiago de Compostela in north-west Spain around 8.40pm on Wednesday.
The train from Madrid to Ferrol was thought to be travelling at 190km per hour (120mph), more than double the 80km per hour limit on that section of the track.
The impact was so great that one of the carriages went up an embankment and came to rest several metres above the rails.
The driver has been identified as 52-year-old Francisco Jose Garzon who was trapped briefly in the cabin and suffered minor injuries.
He has been placed under formal investigation, although had not been arrested last night.
According to Renfe, the state-owned company that operates the train, Mr Garzon said over his radio before the accident that he was going too fast, shouting as he went into the bend: "I'm on 190 km per hour!"
Julio Gomez-Pomar, the president of Renfe, told Cadena Cope, a radio network, that Mr Garzon had been working for the company for 30 years and had been driving trains along the track where the accident occurred since 2010.
The investigation is likely to examine Mr Garzon's Facebook page, which was taken down yesterday but not before Spanish news outlets had seen photographs he had shared of his train's speedometer registering more than 200km per hour.
While human error may have played a part in the disaster, the train's computerised safety systems are also being examined. The curve where the accident happened is controlled by an automatic speed-monitoring system that is designed to stop trains or slow them down if the driver ignores the signals or speed limits.
The train contains a black-box style recorder that is now in the hands of investigators. It was Spain's deadliest train crash in four decades, and 95 people remain in hospital – 36 in critical condition, among them four children.
Prime Minister Mariano Rajoy, a native of Santiago de Compostela, toured the crash scene alongside rescue workers and went to a nearby hospital to visit the injured and their families.
"For a native of Santiago, like me, this is the saddest day," said Mr Rajoy, who declared Spain would observe a three-day period of mourning.
He said judicial authorities and the Public Works Ministry had launched parallel investigations into what caused the crash.
Eyewitness accounts backed by security-camera footage of the moment of disaster suggested that the eight-carriage train was going too fast as it tried to turn left underneath a road bridge.
The train company Renfe said 218 passengers and five crew members were on board.
Spanish officials said the speed limit on that section of track is 80 kilometres (50 miles) per hour.
An estimate of the train's speed at the moment of impact using the time stamp of the video and the estimated distance between two pylons gives a range of 144-192 kph (89-119 mph). Another estimate calculated on the basis of the typical distance between railroad ties gives a range of 156-182 kph (96-112 mph).
The video footage, which the Spanish railway authority Adif said probably came from one of its cameras, shows the train carriages start to buckle in the turn.
Murray Hughes, consultant editor of Railway Gazette International, said it appeared that a diesel-powered unit behind the lead locomotive was the first to derail. The front engine itself quickly followed.
In the background, all the rear carriages can be seen starting to decouple and come off the tracks.
The picture goes blank as the engine appears to crash directly into the camera.
After impact, witnesses said a fire which engulfed passengers trapped in at least one carriage most likely from the diesel fuel carried in the locomotive units.
One eyewitness who lives beside the train line, Consuelo Domingues, said: "I saw the train coming out of the bend at great speed and then there was a big noise."
Santiago officials had been preparing for the city's internationally celebrated Catholic festival but cancelled it and took control of the city's main indoor sports arena to use as a makeshift morgue. There, relatives of the dead could be seen sobbing and embracing each other.
A Spanish train that hurtled off the rails and smashed into a security wall as it rounded a bend was going so fast that carriages tumbled off the tracks like dominos, killing 80 people, according to eyewitnesses and video footage.