The president of the company in charge of Spain's rail infrastructure and his two predecessors have been charged in connection with the fatal train derailment in July.
Seventy-nine people died near the northwestern city of Santiago de Compostela after the driver of a passenger train allegedly lost control and the train flew off the tracks.
The eight-carriage train was hurtling around a bend at 179km/h, more than twice the speed limit, according to data.
Now three men, who are current and former leaders of the company Adif, which manages most of Spain's railway infrastructure, have been charged over a serious lack of action on security issues.
Judge Luis Alaez criticised the disconnection of the rail traffic management system on the stretch of railway, which should cause automatic braking if the speed limit was exceeded.
Judge Alaez said the Adif leaders "allowed this situation to endure until the accident, with a serious risk for people's lives."
But Adif and Renfe, the company that runs the trains, have denied any technical failings and said correct procedures were followed.
The driver of the train, Francisco Jose Garzon Amo, had previously been charged with 79 cases of reckless homicide.
He has been released under court supervision while the investigation into the crash continues.