Spain’s transport minister, Óscar Puente, has resigned six days after a high-speed train collision killed at least 69 people, reversing his decision to remain in office and withdrawing from the forthcoming general election.

Puente announced his departure in Congress on Tuesday evening after a lengthy session in which he outlined new rail safety measures and faced opposition questioning. Dozens were injured in the 28 October collision near Urda, south of Madrid, Spain’s worst rail crash since 2013 and one of the deadliest in modern European history.

“A transport minister in a country like Spain cannot remain in office after two accidents of this seriousness in less than a year,” he said. A January crash on the same line killed 46 people.

The conservative People’s Party, far-right Vox and some government allies had demanded his resignation. They argued that he must take responsibility for a high-speed railway whose credibility Prime Minister Pedro Sánchez acknowledged was “broken”. Opposition parties also accused Puente of using apparent suggestions of human error to divert attention from his own failings.

Puente described his departure as an act of “political dignity”. Sánchez praised him for having “faced up to the situation, provided answers and solutions, and then stepped aside”, presenting the resignation as voluntary and respectful of the victims.

The distinction matters ahead of the early general election on 29 November: remaining risked appearing insensitive, while resigning risked being read as an admission of government fault. Many observers regard the disaster as an electoral setback that Sánchez will be unable to overcome, though that remains a prediction.

The technical questions extend beyond the minister’s departure. A state-owned Renfe train carrying 397 passengers struck a stationary train operated by private company Iryo, carrying 147. A reported computer failure in the automatic signalling system had forced trains to halt.

Three leaked recordings appear to show that Madrid’s control centre authorised the Renfe driver to proceed at normal speed under the Lateral Signalling Block, a back-up system used when automatic signalling or data transmission fails. The Iryo train was stopped about 25km, or 15 miles, ahead.

In separate exchanges, the Iryo driver reported losing communication with the train-control system. After being instructed to resume normally, the driver called again to say the train could not move. That later recording suggests the controller had been notified that it remained stationary as the Renfe train approached.

The recordings raise a specific unresolved issue: how permission to proceed was handled while another train remained stopped ahead. Political responsibility and the precise causes of the collision are separate questions; the resignation does not settle the latter.