According to the Spanish Guardia Civil, the broken rail that caused an Iryo high-speed train (HST) to derail near Adamuz on 18th January 2026 and collide with an oncoming Alvia train operated by Spanish state railway Renfe had already been detected in the track circuit 22 hours before the accident. According to the report submitted on 8th April 2026, the system recorded a voltage drop of 0.5 V lasting for almost a day, which was consistent with a broken rail. However, no warning was triggered because the value remained above the threshold of 0.78 V set by Adif. According to Adif, although the anomaly was recorded, the data is usually only analysed during scheduled maintenance or following faults. Hitachi Rail, the supplier of part of the monitoring equipment, confirmed that the defect was technically detectable, but that the parameters set by Adif did not reflect this. The report was handed over to the investigating judge. In a preliminary report dated 23rd January 2026, the state accident investigation body CIAF had cited long-term damage or a fault in the weld as the most likely cause. Sabotage, terrorism and driver error were ruled out.
