The chaos and horror of Spain’s second rail tragedy this year has been conveyed vividly by survivors of Wednesday’s high-speed crash that has left at least 69 people dead.

But as Spain holds three days of mourning, revelations from leaked audio recordings of the apparent human error in a control room in the minutes before this disaster happened have given way to public disbelief and outrage, in a highly politicised climate, exactly a month before Spaniards go to the polls.

“You don’t know what’s happening, you don’t know what has happened, you just know that you’re being thrown around in a matter of seconds,” said Iñaki García, 60.

He was on the stationary Iryo train that was rammed from behind by a Renfe train on the Madrid-Seville line near Urda, around 140km (87 miles) south of the capital.

“There were people injured, walking around, there were dead people,” he said. “In the next carriage along there were a lot of dead people.”

Recalling the horrific scenes around him, one young man told the BBC in a quivering voice: “I don’t know if that’s something I’ll ever recover from.”

Stories of tragedy have continued to emerge. A pharmacist from Urda was one of the first to reach the scene, bringing with him first aid supplies and medicine.

“One of [the passengers] was saying goodbye to his wife and children. His last words were ‘God is good’,” Antonio García told Spanish radio.