A court statement said investigative magistrate Luis Alaez released Francisco Jose Garzon Amo without bail.
The statement said Garzon must appear in court once a week and is forbidden to leave Spain without permission.
It said the train driver’s licence had also been withdrawn. Earlier, Garzon was questioned for almost two hours at the court in Santiago de Compostela, the northwestern town near where the accident occurred.
The 52-year-old claimed in the immediate aftermath of the accident that he “could not brake,” the court heard.