MADRID — The driver was on the phone with a colleague and apparently looking at a document as his train barreled ahead at 95 mph — almost twice the speed limit. Suddenly, a notorious curve was upon him.

He hit the brakes too late.

The train, carrying 218 passengers in eight carriages, hurtled off the tracks and slammed into a concrete wall, killing 79 people.

On Tuesday, investigators looking into the crash announced their preliminary findings from analysis of the train’s data-recording “black boxes,” suggesting that human error appears to be the cause of Spain’s worst railway disaster in decades.

According to the investigation so far, train driver Francisco Jose Garzon Amo received a call from an official of national rail company Renfe on his work phone in the cabin, not his personal cell phone, to tell him what approach to take toward his final destination.

The Renfe employee on the telephone “appears to be a controller,” a person who organizes train traffic across the rail network, said a statement from a court in Santiago de Compostela, where the investigation is based.

“From the contents of the conversation and from the background noise it seems that the driver (was) consulting a plan or similar paper document.”