The driver of the train that crashed in Spain last week killing 78 people is due to be questioned by a judge.
Francisco Jose Garzon, 52, is set to answer questions about what went wrong by Sunday evening at the latest.
He was detained on suspicion of negligent homicide following Wednesday's crash in Santiago de Compostela.
Blame has increasingly fallen on the driver, with the country's railway agency saying it was his responsibility to brake before going into the high-risk curve where the train tumbled off the rails and smashed into a wall.
But it is still not clear whether the brakes failed or were never used, and the driver has remained silent so far.
Al Jazeera's Sonia Gallego reports.