Spanish police report: Adamuz rail tracks broke day before fatal crash

The latest report from the Guardia Civil’s judicial unit in Cordoba, submitted to the judge investigating the Adamuz rail disaster, reveals that the tracks broke 22 hours before the fatal accident.

According to investigators, a flaw in the configuration of the safety systems at infrastructure firm Adif prevented an automatic alert from being triggered.

In theory, such an alert would have prevented the collision between the Iryo and Alvia trains on 18 January. The disaster claimed 46 lives and left dozens injured after a Malaga-Madrid train derailed and collided with an Alvia service travelling on the opposite track towards Huelva.

In the 70-page report, the Guardia Civil concludes that "the accident originated on the railway line near kilometre marker 318 [...] as a result of a derailment caused by a broken rail." Investigators confirm that a broken rail or weld remains the primary focus of the inquiry.

Analysis of the technical data has revealed that the signalling systems detected an electrical disturbance long before the first train derailed. The voltage in the track circuits is normally maintained at around two volts. However, "from 9.46pm on 17 January, there was a drop to around 1.5 volts and normal voltage did not recover until the accident". This sustained variation is consistent with a crack or break in the steel, as per the Guardia Civil's report.

Despite the technical evidence, the Sam (maintenance support system) passively registered the voltage drop at the Hornachuelos base, near Adamuz, without issuing any warning to traffic control personnel. The police report states that "the signalling system was not configured to automatically alert to such a drop due to the unreliability of the method on this railway infrastructure".

According to statements Adif's supplier Hitachi Rail gave to the police, the system only generates a warning if the voltage drops below 0.780 volts. Since it remained at 1.5 volts, the system interpreted the track as clear and safe.

Investigators consider this subtle voltage drop key. According to Adif's 2017 technical specifications, "the system design must include the ability to detect rail breakage". The Guardia Civil state that Adif, despite its own regulations, "did not demand" this capacity with the necessary rigour for this high-speed line.

The progress of the investigation has also narrowed down the range of possible causes of the fatal accident. The official report is unequivocal in stating that theories of negligent or reckless driving by the train drivers can be "definitively ruled out". Toxicology tests and the analysis by the legal registrars (RJU) confirmed that both professionals acted correctly, describing the accident as "completely unexpected and without any time to react".

Similarly, the investigators have ruled out any indications of "sabotage or terrorism", following negative chemical analyses at the forensic laboratory.

The focus has now shifted to the technical execution of the infrastructure. An investigation is under way to determine if there was "poor welding, either due to the welder's actions or the improper use of the welding kit". Investigators discovered that a 350HT kit was originally used at the kilometre marker of the accident to join rail coupons, whereas Adif's regulations stipulated the use of the R260 kit.

Although Adif submitted a "correction" alleging a recording error by the welder, the railway accident investigation commission (CIAF) has detected "inconsistencies" and raised doubts about the validity of the signatures on the documentation provided by the subcontractors.

The report also casts doubt on the effectiveness of the previous inspections. Although ultrasonic surveys were carried out in June 2025, which deemed the area "safe", the Guardia Civil discovered that the technicians in charge did not strictly meet the requirement of "demonstrating a minimum of two years' experience" at the time of the inspection. Furthermore, the company Redalsa informed the investigators that "there is no digital record of the raw data generated" during those inspections, citing technical limitations of the handheld equipment.

In addition, just two months before the tragedy, a dynamic inspection detected a "vertical acceleration defect" at the exact point of the break. This data was incorporated into monitoring efforts which, in light of the events, proved insufficient to detect the material fatigue that ultimately caused the collapse of the rail line built by Ensidesa in 2023.