Details of the collision
The accident occurred when a state-operated Renfe high-speed train collided with the back of a stationary train operated by the private company Iryo. According to Puente, a computer failure in the automatic signalling system had forced all trains to halt on the affected stretch of track, but the Renfe train was later ordered to proceed "in error."
Leaked audio recordings published by Spanish media outlets, including El Pais and RTVE, show conversations between Madrid's control centre and train drivers. The recordings suggest that one high-speed train was given clearance to move even though another train was stopped on the track approximately 25km (15 miles) ahead. In one recording, a control operator told a Renfe driver to "Continue your journey and then proceed under [Lateral Signalling Block], at normal speed with normal operation."