Spain has started three days of national mourning following a tragic train collision near Adamuz in Córdoba province that killed at least 40 people and injured dozens more. The accident happened on Sunday night when a Madrid-bound train carrying about 300 passengers derailed and hit an oncoming train. Rescue teams are still combing through the wreckage to find victims. Many families are desperately searching for missing loved ones. Juan Barroso said five family members were on the train; only a six-year-old child has been found so far. People are posting pictures on social media and police have set up offices for DNA identification. Prime Minister Pedro Sánchez visited the site and said, "Spanish society, like all of us, is wondering what happened, how it happened, how this tragedy could have occurred," adding, "I’m convinced that time and the work of experts will provide us with those answers." The collision occurred just before 8pm when the rear of the Madrid-bound train derailed and hit the southbound train. This caused the first two carriages of the other train to come off the track and fall down a 4-metre slope. Transport Minister Óscar Puente said the derailment on a straight, renovated track was "really strange." The train involved was less than four years old and inspected just days ago. Renfe's president Álvaro Fernández Heredia ruled out human error for now and called the conditions "strange." A source revealed a broken joint on the rails might have widened over time, possibly causing the crash. Since 2022, several infrastructure issues were reported in the area, including signalling and power line problems. The train drivers’ union warned about increased track wear from heavy rail traffic but said the cause remains unknown. Emergency teams faced difficult conditions in a remote area and worked overnight to rescue trapped passengers. Some escaped by breaking windows with emergency hammers. Adamuz’s mayor called the scene "horrific" and the town is in shock. Authorities warn the death toll may rise due to the wreck’s severity, with bodies found hundreds of metres from the site. Spain’s high-speed rail network, celebrated as the largest in Europe and second in the world, carries millions of passengers yearly. This disaster shakes a source of national pride and prompts a thorough investigation.