A Madrid-bound train run by private company Iryo derailed and crossed on to the opposite tracks, striking a south-bound train heading to Huelva, run by state rail company Renfe. Most of those killed and injured were in the front carriages of the Renfe train. The incident is Spain’s deadliest rail crash in more than a decade.

As a result of the crash, the major high-speed rail line between Madrid and Andalucía was suspended for a month, reopening on 17 February.

According to Spain’s rail investigation commission, the CIAF, a gap of almost 40cm was found at a welded joint in the track. The commission reported that the Iryo train’s front carriages – which did not derail – had “notches” in their wheels consistent with striking a broken section of rail. Similar damage was also identified on three trains that went over the track earlier the same evening.

It is suspected that an alleged aluminothermic weld (a common method for joining rails) or weakness in the welded area caused the derailment. The new rail was installed in mid‑2025 and joined to an older rail, which isn’t unusual but is under review.

For now, the contractors under investigation are engineering and construction company Azvi, train operators Iryo and Renfe and the rail supplier ArcelorMittal.

Laboratory tests are also needed for metallographic analysis of the rail samples as well as a review of the black box data, and further calculations to determine whether the fracture came from a bad weld, material defect or fatigue from use.

Another deadly crash

The second accident occurred just two days later, on Tuesday 20 January. A trainee train driver was killed and at least 41 passengers were injured after a commuter train collided with a retaining wall that had fallen onto the tracks between Gelida and Sant Sadurní, near Barcelona.

Rail officials believe the wall collapsed at approximately 9pm, striking the driver’s cab first before causing significant damage to the train’s first carriage.

The crash took place as heavy storms battered north-eastern Spain, with coastal areas on high alert due to severe weather conditions.

Whether the cause was human error, insufficient maintenance or a structural defect, public confidence is unlikely to recover until a transparent investigation is conducted and concrete solutions are implemented. Until then, many Spanish citizens are refraining from using the country’s rail network.