Relatives of the 57 people who died in Greece's worst ever train disaster crowded into a courtroom on Wednesday, demanding justice for the victims.
The trial had already been postponed once because of the chaotic start last week.
Most of the victims of the crash three years ago were students, killed when their intercity service from Athens to Thessaloniki smashed head-on into a goods train on the same line near Tempi in the centre of the country.
Some of the victims are thought to have burnt to death after surviving the initial collision.
Many relatives were unable to get into the courtroom in the central town of Larisa last week, and the situation was little different when it resumed on Wednesday.
