A contractor stationmaster working for Hellenic Railways was conditionally released on Monday after testifying about his role in a February 28 rail disaster that claimed 57 lives.
The stationmaster must appear at his local police station and is banned from leaving the country.
He is said to have claimed he did not leave his shift early; his shift ended at 10 p.m. on the night of February 28, and he left at 10.15 p.m., he has said.
Authorities are investigating whether he and a veteran staff member of Hellenic Railways left their posts early, leaving an inexperienced colleague to steer two trains running in opposite directions on the same track, resulting in a head-on collision.
Both were employed in the Larissa train station, an important rail hub in central Greece, just south of the accident site.
The more experienced staff member will face an examining magistrate and a prosecutor on Tuesday.