What to know about the multiple train crashes in Spain this week

MADRID — Multiple train crashes this week have rocked Spain, with the tragedies leading to questions about safety on the country's vast railway system.

The first crash involved a high-speed train in southern Spain that derailed on Sunday evening, colliding with another fast train, killing at least 45 people and injuring more than 150.

The crash was the deadliest in Spain since a 2013 crash that killed 80 people when a commuter train in the northern region of Galicia hurtled off the rails as it came around a bend going too fast.

On Tuesday night, another train crash happened in northeastern Spain on a commuter line near Barcelona. One person was killed.

Then, on Thursday, a commuter train crashed in southeastern Spain, slightly injuring six passengers.

Here's what to know.

Derailment and collision

The head of the second train took the brunt of the impact, Transport Minister Óscar Puente said. That collision knocked its first two carriages off the track and sent them plummeting down a four-meter (13-foot) slope. The collision took place near Adamuz, a town in the province of Cordoba, about 370 kilometers (about 230 miles) south of Madrid.

''The impact was so incredibly violent that we have found bodies hundreds of meters away,'' Andalusia regional President Juan Manuel Moreno said.

Authorities said they had identified almost all the victims from Sunday's crash.

Cause under investigation

Explanations about what caused the crash were scant, with an official investigation underway, but some details have started to emerge.

What caused the apparent fracture isn't known, investigators said, not ruling out any possibilities.

''These nicks in the wheels and the deformation observed in the rail are consistent with the rail being fractured,'' the report said.

Álvaro Fernández, the president of national railway company, Renfe, has said that both trains were traveling well under the speed limit of 250 kph (155 mph) and ''human error could be ruled out.''

The train that jumped the track belonged to the private company Iryo, while the second train, which took the brunt of the impact, belonged to Renfe.

Iryo said in a statement Monday that its train was manufactured in 2022 and passed its latest safety check on Jan. 15.

It warned of potholes, bumps and imbalances in overhead power lines, as well as frequent breakdowns and damage to trains, according to a copy of the letter seen by The Associated Press.

The union called for a general strike in the coming weeks to demand more safety assurances.

High-speed expansion

Spain has spent decades investing heavily in high-speed trains. It currently has the largest rail network in Europe for trains traveling more than 250 kph (155 mph), with more than 3,900 kilometers (2,400 miles) of track, according to the International Union of Railways.

The network is a popular, competitively priced and safe mode of transport. Officials said that Sunday's collision was the first with deaths on Spain's high-speed rail network since it opened its first line in 1992.

A Barcelona commuter train crashed Tuesday after a retaining wall fell onto the tracks, Spanish regional authorities said, killing one person and injuring at least 37 others.

A commuter train crashed on Thursday in the southeastern Murcia region after it collided with a crane. Emergency services said six people with minor injuries had been transferred to the hospital.