Emergency services treated more than 150 people but none with serious injuries, authorities said, after two trains collided in Montcada i Reixac, north of Barcelona.
Dozens of people have reportedly been hurt after two commuter trains collided near Barcelona.
Catalonia's civil protection authorities say the emergency medical service has treated at least 155 people, but none with serious injuries. Three people with minor injuries have been transferred to hospital, they added.
Officials say that the collision occurred on a train line in Montcada i Reixac, a town just north of Barcelona.
A train travelling towards Barcelona hit the rear of another train also heading to the city at Montcada station, according to the state railway company Renfe.
The incident forced the Civil Protection alert plan for railway accidents to be activated.
The affected trains were on Renfe's R4 commuter line, which was paralysed, as were two other lines, in both directions.
The fire brigade, which sent seven teams to help transfer the injured to ambulances, was quoted as saying that no passengers were trapped and the two trains had been completely evacuated.