Earlier this week, Spanish Transport Minister Óscar Puente confirmed reports that grooves were found on the wheels of the Iryo train’s carriages, which had passed over the track safely.
“These notches in the wheels and the deformation observed in the track are compatible with the fact that the track was cracked,” the CIAF preliminary report said.
It added that three trains that had gone over the tracks at 17:21 on Sunday, 19:01 and then 19:09 had similar notches “with a compatible geometric pattern”.
Similar grooves are found on carriages two, three and four of the Iryo train, the report says, but carriage five – the last that did not derail – had a groove on its outer edge, suggesting the rail was already tilting outwards before carriage six derailed.
The CIAF called its report a “working hypothesis”, adding that it “must be corroborated by later detailed calculations and analysis”.
The transport minister appeared before reporters again on Friday to say that it was too early to have definitive answers, but that if the cause of the crash was the fracture, then it occurred in the minutes and hours before the derailment and could not have been detected.
The Adamuz disaster is is the country’s worst rail crash in more than a decade.
In 2013, Spain suffered its worst high-speed train derailment in Galicia, north-west Spain, which left 80 people dead and 140 others injured.