The driver of the train that derailed in northern Spain last week killing 79 people was talking on the phone at the time of the accident.

Analysis of the train’s data recording device showed that Francisco Garzon, 52, was on the phone with state train operator Renfe.

The initial reading of the so-called black box, released by the court investigating the case, also showed the train was travelling at 192km per hour in the minutes before it derailed in a curve where speed is limited at 80km per hour.

The eight-carriage train had slowed to 153km per hour at the time of the crash after a brake was activated seconds before, the black box showed.

Mr Garzon was freed from police custody on Sunday pending trial on charges of negligent homicide.