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; however, Sunday's collision took place on the oldest AVE route connecting Madrid with Andalusia.

Several officials, including the president of Renfe, the national rail operator, Álvaro Fernández Heredia, assert that human error was almost certainly not the cause, given that neither train was travelling at excessive speed.

Transport Minister Óscar Puente stated that the carriage number six of the train was going to be examined closely, as it was the first to derail and could provide many pieces of the puzzle.

Investigators are also examining the section of track where the derailment occurred and will analyze parts in a laboratory. Reports have emerged indicating that part of the track was broken at the crash site.

However, the government has urged caution regarding premature conclusions, emphasizing that damage may have occurred due to the collision's force.

The investigation has also revealed that over the last year, anomalies regarding signalling and operational issues on the line where the accident occurred were communicated by rail infrastructure administrator Adif.

The government has recently reduced the speed limit for the AVE along a stretch between Madrid and Barcelona, citing concerns regarding the state of the line.

Following the incident, many social media users flagged past complaints about the discomfort while travelling on AVE trains, emphasizing the need for a deep review of the high-speed rail network's condition.

Prime Minister Pedro Sánchez stated, When we find the answer, with absolute transparency we will make it known to Spaniards,” during his visit to Adamuz, hinting at the investigation's potential impact on the future of Spain’s rail system.