A commuter train derailed on Tuesday after a retaining wall collapsed onto the track during heavy rain near Barcelona, killing the driver and seriously injuring four passengers.
A third derailment of a train on Barcelona's regional network, which left no injuries, was caused by a rock falling on the line during the same storm, rail network operator Adif said.
"We are going to demand criminal liability from those responsible for ensuring safety in the railway infrastructure," the train drivers union SEMAF said in a statement.
Those accidents occurred just two days after the derailment of a high-speed train on Sunday near Adamuz in Cordoba province, about 360 kilometres south of Madrid, which caused a collision with another train that killed 42, including the driver of the oncoming train.
SEMAF had warned Adif in a letter last August of severe wear and tear to the railway track where the two trains collided, according to a copy of the letter seen by Reuters.
The letter said potholes, bumps, and imbalances in overhead power lines were causing frequent breakdowns and damaging the trains on several of the network's high-speed lines.
Rescuers at the site of the Adamuz crash were prising apart the second carriage of the train belonging to state operator Renfe, which contained its cafeteria, to see if any more bodies could be found, the Andalusian regional government said in a statement.
Overnight they had used cranes to remove one of the final carriages of the derailed train run by private consortium Iryo from the scene.
Adif said on Wednesday it had introduced a further speed limit on the Madrid-Barcelona line after a driver had reported poor conditions on the track in a 78-kilometre stretch.
On Tuesday, it had ordered drivers to limit their speed because of concerns about the state of the track. Its maintenance team had worked overnight to inspect the line and found four points that needed to be repaired, Adif said in a statement.
The accidents are causing chaos for commuters and travellers, who were scrambling for alternatives. Regional trains across Catalonia were suspended on Wednesday to allow for track inspections after the recent storms.
Renfe posted a photo of its President Alvaro Fernandez Heredia using a replacement bus service as he travelled back to Madrid from Adamuz.
