"We are really feeling the impact. People are praying. It is a great tragedy," said 70-year-old Marlen de Francisco, who sells souvenirs in the cathedral square.
"All day people are asking me for note paper so they can write messages and put them on the cathedral gates.
The president of the Spanish rail network administrator ADIF, Gonzalo Ferre, said Garzon had been warned to start slowing the train "four kilometres before the accident happened".
A resident who rushed to the scene said in a television interview broadcast Sunday that the driver told him minutes after the crash he had been unable to brake.
"He said he had to brake to 80 and couldn't, that he was going fast," Evaristo Iglesias told Antena 3. Along with another man, he said, he had accompanied the driver to a stretch of flat land where other injured people were being laid out after the accident.
"He kept saying 'I want to die! I want to die! I don't want to see this!".
State railway company Renfe said the driver had been with the firm for 30 years, including 13 years as a driver, and had driven trains past the spot of the accident 60 times.
El Mundo newspaper on Sunday printed extracts from the train's route plan, indicating that ahead of the bend the train passed from a stretch of track with a speed limit of 220kph to one with a limit of 80kph.
The newspaper said it was "surprising" that it was left entirely up to the driver exactly when to brake as the train entered the curve.
Some media reports described Garzon Amo as a speed freak who had once posted a picture on his Facebook page of a train speedometer at 200 kph.
Renfe said the train had no technical problems and had just passed an inspection on the morning of the accident.
But the secretary general of Spain's train drivers' union, Juan Jesus Garcia Fraile, told public radio the track was not equipped with braking technology to slow the train down automatically if the driver failed to do so when required.
Many of the passengers were said to be on their way to a festival in honour of Saint James, the apostle who gave his name to Santiago de Compostela.
"As a believer, I wonder how Saint James can have allowed this to happen," said Pedro, a grey-bearded pilgrim from Cantabria in northern Spain, wearing a cape and using a walking stick.