An Associated Press analysis of video images suggests that the train may have been travelling at twice the speed limit for that stretch of track.
Spain's government said two probes have been launched into the cause of last night's crash near this Christian festival city in northwest Spain. The Interior Ministry raised the death toll to 80 in what was Spain's deadliest train wreck in four decades, while 95 remained hospitalised, 36 in critical condition, among them four children.
"For a native of Santiago, like me, this is the saddest day," said 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 per hour.
The video footage, which the Spanish railway authority Adif said probably came from one of its cameras, shows the train carriages start to buckle soon into the turn.