Madrid (CNN) -- The judge investigating the train crash that killed 79 people last July is expanding the preliminary charges to include numerous top officials of the state railway infrastructure company, Adif, for alleged negligence, a Tuesday court order shows.
Judge Luis Alaez Legeren wrote that five Adif officials in charge of track and signal security, along with the current and two former Adif presidents, will face preliminary charges because there was no safety system that would have compensated for any human error by the train driver.
The prime suspect remains the driver, Francisco Jose Garzon, who already faces preliminary charges of 79 counts of homicide by professional recklessness.
The judge's latest order states that the passenger train was going more than twice the speed limit when it derailed on a curve near the northwest city of Santiago de Compostela. In addition to 79 fatalities, some 170 passengers were injured.
Just before the crash, the driver took a phone call from another official on the train to discuss the train's route farther north on the journey, the judge wrote.
An Adif spokeswoman said the company had no immediate comment about the judge's order, and company lawyers were studying it.
In the eight-page order sent by the court to reporters, the judge cites various security systems in place along the section of track where the accident occurred. But he adds it appears that Adif officials did not adequately mitigate all the predictable scenarios of human error by the driver.
Since the accident, the speed limit at the curve has been reduced from 80 kilometers per hour (50 mph) to just 30, Adif has confirmed.
Last week, Spanish newspaper El Pais exclusively obtained audio of the driver's first, desperate phone call, while injured and still trapped inside the engine, to the train's control center.
The court said it did not release the audio, but there are several parties to the case who may have had access to it.
In the audio, the driver told his control center he "got distracted" and was going 190 kilometers an hour when he should have been doing 80.
News media reported that part of the conversation in the days after the crash, citing officials, who blamed excessive speed for the crash.
But the audio recording also contains allegations by the driver that were not widely reported weeks ago, namely his contention that he had warned authorities about what he called the dangerous curve.
"I had already told security it was dangerous, that one day we were going to eat it, and it happened to me," the driver, Garzon, is heard telling the control center in the audio recording.
A few moments later he added, "Oh God, I had already told the people from security that it was very dangerous. We are human ... and this can happen... that this curve is inhumane. Understand? If there was a warning light ..."
For weeks, the judge has been investigating other potential causes for the accident, beyond the train's excessive speed.
In the court order Tuesday, he also asked Adif to provide the names of all company board members and all rail security senior officials, since December 2011. That's when the section of track where the accident occurred, and its security systems, went into operation.