Garzon also explained a photograph on his Facebook page which showed a train speedometer registering 124 mph (200 kph). He said he took the photo "as a laugh or whatever you want to call it" while a colleague was driving a test train on a different track some time ago. His Facebook page was taken down shortly after the crash. It is not known who removed it.
The investigating judge is trying to establish whether human error or a technical failure caused the country's worst rail accident in decades, and Garzon is at the center of the investigation.
The judge provisionally charged Garzon on Sunday with multiple counts of negligent homicide. Garzon was not sent to jail or required to post bail because none of the parties involved felt there was a risk of him fleeing or attempting to destroy evidence, according to a court statement.
National rail company Renfe said Garzon is an employee with 30 years of experience who became an assistant driver in 2000 and a fully qualified driver in 2003.
Garzon went back to court, voluntarily, to offer more testimony on Wednesday.
In that second appearance, he said he was talking by phone to the train's on-board ticket inspector moments before the accident and hung up just before the train left the tracks. But that contradicted what the court said the black boxes showed — that Garzon was on the phone at the time of the derailment.
The court said the inspector would testify Friday as a witness. It said the judge has ruled that while the phone call was inappropriate it could not be considered a cause of the accident.
Health authorities say 57 people from the crash are still in the hospital, 11 of them in critical condition.
Hatton contributed from Lisbon, Portugal. Associated Press writer Jorge Sainz contributed from Madrid.
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