Sunday's high-speed train crash in southern Spain, the worst in over a decade, has been a devastating tragedy for the country, with the loss of at least 42 lives.
Amid the grief, many are asking what could have caused such a failure on one of Europe's most admired rail systems.
The CIAF rail investigatory commission has started analysing why a train travelling north from Málaga was derailed on a straight section of the route, causing it to collide with an oncoming train, which was also derailed.
The Spanish government has described the accident as extremely strange.
Three bodies already located in the wreckage were recovered on Tuesday afternoon, and a 42nd victim was also found at the crash site near Adamuz.
The shock felt in this sleepy town has been compounded by confusion at how a rail route that ran efficiently for so long suddenly failed.
After its inauguration in 1992, Spain's high-speed rail, or AVE, network was seen as a symbol of the country's modernisation. Built with EU funds, it provided a state-of-the-art transport system that was fast, efficient and safe.
A derailment near Santiago de Compostela in 2013 that killed 80 people was not part of the AVE network, although that train was travelling at high speed. Sunday's collision, however, took place on the oldest AVE route, that which connects Madrid with Andalusia.
Several officials, including the president of Renfe, the national rail operator, Álvaro Fernández Heredia, said that human error was almost certainly not the cause of the accident, given that neither train was travelling at an excessive speed. Interior Minister Fernando Grande-Marlaska insisted that sabotage was not a possible cause.
Inevitably, investigators are looking closely at the train that derailed. Owned by Italian firm Iryo, it was manufactured in 2022. Transport Minister Óscar Puente said that carriage number six of the train was going to be examined closely, because it was the first to derail and it offered many pieces of the puzzle.
However, investigators are also examining the section of track where the derailment occurred and intend to analyse parts of it in a laboratory.
The revelation that part of the track at the crash site was broken has encouraged speculation that this might be the culprit. The government has been keen to play down such conclusions, pointing out that the track may have been damaged by the force of the collision.
Adif has reduced the speed limit for the AVE along a 150-km (93-mile) stretch between Madrid and Barcelona, due to concerns about the state of the line. The new limit along that section is 160km/h, nearly half the previous limit.
Prime Minister Pedro Sánchez has declared three days of mourning during his visit to Adamuz, pledging that the government would provide answers with absolute transparency.
This tragedy serves as a significant reminder of the importance of maintaining safety in the infrastructure of essential services, shaping the future of Spain's renowned rail system.
