SANTIAGO DE COMPOSTELA (REUTERS) - Spanish police were investigating on Friday if the driver of a train that crashed in Santiago de Compostela killing dozens had been driving at reckless speed when he took a tight curve.
Spain's worst train wreck in decades on Wednesday evening killed at least 78, with six bodies still unidentified and 95 people in hospital, immediately raising questions about why an experienced driver was travelling so fast into a sharp bend.
The driver, Mr Francisco Garzon, 52, was under arrest in a hospital in the city in northwestern Spain and was due to give a statement to police later on Friday.
Mr Garzon was being investigated for criminal behaviour in causing the accident and "recklessness", regional police chief Jaime Iglesias said.
A spokeswoman for the supreme court in the Galicia region said Mr Garzon had not yet been charged and evidence including the train's "black box" was being assembled.
"We're collecting elements to be used as evidence, videos, audios and all the technical work that is being done on the train," she said.
Renfe, the Spanish state train company, said Mr Garzon was a 30-year company veteran who had been driving for a decade. He was highly qualified and had been driving on the line where the accident took place for about a year.
On the morning of the tragedy, he had driven a train on the same line, which connects La Coruna with Madrid, and a Renfe spokesman said he knew every twist and turn of the route.
It has been widely reported that he took a sharp curve with an 80kmh speed limit at more than twice that speed.
The driver was not available for comment and Reuters was not able to locate his family or determine whether he has a lawyer.
Another train driver on that line told Cadena Ser radio that the blame should not be put on his colleague.
"There is no security warning for the speed, it's pure human factor, you have to slow down manually and you have no assistance in the cabin," said Mr Manuel Mato.
"When you exit the high-speed section you start slowing down... you have like 4km (2.5 miles) to the curve," he added.
While police and a judge were looking into potential negligence on the part of the driver, the Public Works Ministry launched a more technical investigation. Renfe and Adif, the state track operator, began their own probes.
Investigators wanted to know why was the train going so fast? Did the driver fail to heed speed limits? Did brakes fail? What about the safety system meant to force the train or the driver to slow down if going too fast? Security video footage 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.
The impact was so strong that one carriage flew over a wall and landed on an embankment several metres above.
The train involved, made by Bombardier and Talgo, was a series 730 that Renfe uses for its Alvia service, which is faster than conventional trains but not as fast as the AVE trains that criss-cross Spain at even higher speeds.
The train was built in 2007-2009, but remodelled in 2012 to use diesel.
The train is designed to operate on conventional and high-speed tracks that make use of two different types of safety systems that are meant to regulate excessive speed.
On high-speed lines, trains use the European Train Control System, or ETCS, which automatically slows down a train that is going too fast.
On slower lines, trains operate under an older system called ASFA, a Spanish acronym for Signal Announcement and Automatic Braking, which warns the driver if a train is moving too fast but does not automatically slow it down.
At the site of the disaster, just 3km before reaching the Santiago de Compostela station, the train was passing through an urban area on a steep curve. At that point of the track, two railway experts said, it uses the older ASFA safety system.
Professor Roger Kemp, a Fellow of the Royal Academy of Engineering in Britain, said in an e-mailed comment that as the driver was leaving the high-speed line to join a much slower route before entering the station, there must have been at least prominent visual warnings to reduce speed, if not audible warnings and an electronic speed supervision system.
A source close to ADIF said the safety system was apparently working correctly and a train had passed an hour earlier with no problems.
The train, packed with families visiting relatives and revellers on their way to a religious festival, was not running late.
It began its seven-hour journey to the northern region of Galicia right on time: at 15.00 CET on the dot. It crashed at 8.41pm on Wednesday(2.41am on Thursday in Singapore), two minutes before it was due to arrive.