The expected arrival on Monday of heavy machinery to clear the site of the collision between two high-speed trains in Spain could allow rescuers to discover more bodies and increase the death toll from this disaster which has already claimed at least 39 lives.

A rising balance sheet

The death toll from the tragedy that occurred Sunday evening in Andalusia rose sharply overnight, reaching 39 on Monday morning, according to a spokeswoman for the Ministry of the Interior.

"In the coming hours, heavy machinery will begin work and lift the most damaged carriages of the Alvia train. It is unfortunately very possible that other deceased persons will be discovered under the piles of scrap metal. The objective is to identify the victims as quickly as possible," warned the Andalusian regional president Juan Manuel Moreno.

The disaster also left more than 120 people injured. As of midday Monday, 48 were still hospitalized, including 12 in intensive care, according to emergency services.

- What happened?

The collision took place at 7:45 p.m. (6:45 p.m. GMT) near Adamuz, about 200 km north of Malaga.

The cause: an Iryo train (a private rail transport operator) bound for Madrid carrying some 300 people, which derailed and veered onto the parallel track, hitting another train of Renfe, the Spanish national company, travelling in the opposite direction towards Huelva (south), with 184 passengers on board.

The rear carriages of the Iryo train derailed and collided with the first two carriages of the other train, throwing them "off the rails" due to the force of the impact, according to Transport Minister Oscar Puente.

According to Iryo, the last overhaul of the damaged train took place last Thursday.

Aerial images released by the Civil Guard show the two trains quite far apart.

Completely derailed, the four carriages of the Renfe train overturned, and two of them appear to have been crushed by the impact. Several hundred meters further on lies the red Iryo train, which likely continued on its trajectory after the collision, with most of its carriages still on the tracks and its last two lying on their sides.

The causes are still unknown.

The Minister of Transport described the accident as "extremely strange".

"How is it possible that on a straight line, on a renovated section of track, with an almost new train, an event of this nature could occur?" Oscar Puente wondered during the night: "All railway experts (...) are very surprised by this accident."

"Human error is practically ruled out," Renfe President Álvaro Fernández Heredia also assured on public radio RNE. "It must be related to Iryo's rolling stock or an infrastructure problem," he estimated.

On this straight section of railway, limited to 250 km/h, speed was not a factor in the accident, he also assured, pointing out that one of the trains was traveling at 205 km/h, and the other at 210 km/h.

"For now, the Civil Guard is focusing on identifying the victims and the forensic work. At this stage, the investigation is being carried out by the Commission of Inquiry into Railway Accidents," Rosa Reina, a spokesperson for the Civil Guard, told the press in the village of Adamuz.

Spain in shock

Spanish Prime Minister Pedro Sánchez cancelled all his appointments on Monday to travel there, where he is expected later in the day.

The Spanish royal family is expected to visit the area near the accident site on Tuesday.

Several European leaders, including Emmanuel Macron and the German Chancellor, offered their condolences. Pope Leo XIV said he was "deeply saddened".

At Atocha station in Madrid, the consequences of this accident are having a major impact on train traffic, which is completely halted towards Andalusia. "Cancelled" lights are flashing on the display screens, an AFP journalist observed.

Mireia Jiménez, a 55-year-old cook, lives in Malaga and spent the weekend in Madrid. She was supposed to return to the south on Monday afternoon: "They are not offering us any options, they say there will be no trains before Wednesday," she explains.

In July 2013, Spain had already been devastated by a train derailment shortly before its arrival in Santiago de Compostela (northwest), killing 80 people.