Crucially, at one point a controller instructed a stalled train to restart, clearing it to advance at up to 160km/h (100 mph) even though a second train was stuck on the line up ahead.
The impending collision was clear from audio calls and on big screens in the control centre in Madrid.
“They worked. We checked. They could see what was happening,” Puente confirmed. But the advancing train was never ordered to stop.
“I’m no judge… But these are the facts.”
So would he take personal and political responsibility anyway, and resign? Puente called it his “duty”, rather, to remain as minister.
“I’ll face up to things, explain, elucidate,” he countered. “I’ll think how to improve the system, and give confidence to those who want to travel by train and feel calm and safe.”
But Spaniards will take a lot of persuading.
“This is not only a very serious accident, but the second in a very short time,” Paco Camas of the pollster Ipsos points out.
An investigation into January’s crash in Adamuz, near Cordoba, is still open, with initial reports suggesting there was a crack in the rails – very different to the latest collision.
But there is a similar impact.
“It destroys people’s confidence not only in the railways but institutions in general,” Camas warns. “And in Spain when such things happen, we know that people blame their government.”
For Team Sánchez it is the latest in a spiral of crises.
Allegations of corruption against the prime minister’s close relatives still persist, all denied.
Then there was a sudden influx of migrants from Morocco this summer to the Spanish exclave of Ceuta. That got right-wing opponents shouting about incompetence and underfunding.
Later, a video of a pensioner being forcibly evicted from her home went viral and sparked street protests.
That’s when Sánchez called an early election.
His chances of winning the vote looked slim even before the train crash. Now they have plummeted.
