Shock of rail tragedy gives way to sorrow and outrage in politically divided Spain

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 that allowed the disaster to happen 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.

Sánchez's transport minister, Óscar Puente, made clear from the start that a computer failure followed by human error was the likely cause of the crash. By late evening, leaked audio recordings of a control-room operator talking to train drivers appeared to back that up.

Puente has long been a hate figure for the right, and with two of the worst rail tragedies in Spanish history taking place on his watch, the criticism is only going to increase.

Spain's biggest train drivers' union Semaf condemned the leak of audio recordings as irresponsible and slanted. The union had already called a strike for Thursday in a bid to ensure that "urgency to travel is never prioritised over safety".

One train driver, Vicente Almenar, told Spanish media: "They always look for the last link in the chain, where it's weakest, but here the entire procedure failed because we don't even know what our colleague was seeing on the screen," he told Spanish media.

Sánchez had not been expecting rail safety to dominate his campaign, but that now looks increasingly likely.

After two accidents and more than 100 deaths on the same high-speed line, Feijóo told reporters in Urda on Thursday: "The Spanish people need answers. They are wondering what is happening to high-speed rail in their country."

And he emphasised that politics was not about talking - it was about acting.