The Adamuz train disaster, in which 45 people lost their lives on January 18th after an Iryo train derailed and collided with an Alvia , was reportedly caused by a broken weld on the Malaga-Madrid high-speed line , which connected an existing section of track to a newly installed one. Sources familiar with the preliminary investigations by the Commission for Investigating Railway Accidents (CIAF), cited by Spanish media, reported this. CIAF is focusing its investigation on the fracture in the track, which occurred before the Iryo passed, and on compatible marks also found on other trains that passed through the same location—at km 318—shortly before the train disaster.

According to Transport Minister Oscar Puente, the section had recently been renovated, with work completed last May at a total investment of 700 million euros, and the broken track is "new," manufactured in 2023 and installed in May 2025, with all the required quality and traceability certifications. Puente cited a "possible manufacturing defect" among the possible causes and ordered ADIF (the infrastructure manager) to inspect all batches of track from the same supply. For his part, ADIF president Luis Pedro Marco de la Pena explained that the "breaking point" of the track coincides with a weld that joined an existing track to a newly installed one , following the line's modernization works in May.

The point is approximately 80 meters from a railway switch , considered one of the most critical elements of the route due to the increased wear it suffers from the passage of trains. De la Pena also emphasized that any liability will be assessed only after the CIAF's final report , emphasizing that ArcelorMittal, the track supplier, is "a reliable and leading company." In a statement, CIAF confirmed that it will await the official conclusions of the investigation before making any assessment, reiterating its "full willingness to cooperate" with the authorities and specifying that it has not yet received any specific requests for information.