A commuter train has derailed after a containment wall fell on the track ​due to heavy rain near the Spanish city ⁠of Barcelona, killing the driver and injuring about 20 people.

The crash in Catalonia in north-eastern Spain ‌came just ​two days after a high-speed train collision ‍and derailment near Adamuz in the southern Córdoba province that killed 42 people and injured dozens more on Sunday.

Authorities said 20 ambulances were dispatched to the site of the second accident in Gelida on the outskirts ​of Barcelona, along with ‌38 firefighter units.

Gelida is about 35 minutes outside of Barcelona.

Spanish railway operator ADIF said the containment wall likely collapsed due to heavy rain that swept across the region this week.

The Barcelona crash came as emergency workers searched for more victims in the wreckage of Sunday’s deadly train accident in the country’s south, and as the nation began three days of mourning for the victims.

Antonio Sanz, the regional health minister of Andalusia, where Sunday’s accident occurred, told Spanish media that the official toll had risen after another corpse was discovered in a severely damaged car.

Health authorities said 39 people remained in hospitals on Tuesday morning, while 83 people were treated and discharged.

Sunday’s crash happened at 7.45pm, when the tail end of a train carrying 289 passengers on the route from Malaga to the capital, Madrid, derailed and crashed into an incoming train travelling from Madrid to Huelva, another southern city, according to rail operator Adif.

The front of the second train, which was carrying 184 people, took the brunt of the impact, which knocked its first two carriages off the track and down a four-metre slope. Some bodies were found hundreds of metres from the crash site, according to Andalusia regional President Juanma Moreno.

Associated Press images taken Tuesday showed the remains of the first two cars of the second train, severed from the rest of the train and lying beside the tracks. Train seats had been ejected onto the rocks that provide packing under the tracks.

Officials continue to investigate the causes of the accident. Spanish Transport Minister Óscar Puente said it was “truly strange” as it occurred on a straight line and neither train was speeding.

Puente said officials had found a broken section of track that could possibly be related to the accident’s origin, while insisting that was just a hypothesis and that it could take weeks to reach any conclusions.

“Now we have to determine if that is a cause or a consequence [of the derailment],” Puente told Spanish radio Cadena Ser.

So far, “all hypotheses are open”, Interior Minister Fernando Grande-Marlaska Grande Marlaska said. Accident investigators would analyse “the rails at the point where the derailment began and inspect the wheels” of the first train in a laboratory, he said.

The train that jumped the track belonged to private company Iryo, while the second train belonged to Spain’s public train company, Renfe.

The accident shook a nation that leads Europe in high-speed train mileage and takes pride in a network that is considered at the cutting edge of rail transport.

“It is undoubtedly a hard blow, and I have to work so it doesn’t affect the credibility and strength of the network,” Puente told Spanish national radio RNE on Tuesday when asked about the damage to the reputation of the rail system.

Prime Minister Pedro Sanchez visited the accident site on Monday, declaring three days of mourning with flags lowered on all public buildings and navy vessels.

Spain’s King Felipe and Queen Letizia visited on Tuesday.

Meanwhile, Spain’s Civil Guard is collecting DNA samples from family members who fear they have loved ones among the unidentified dead.

-AAP