Spanish unions called off a three-day railway strike on Monday after reaching an agreement with the government over safety and maintenance standards demanded following two accidents that claimed 47 lives.

The back-to-back disasters in January rocked the sector and raised doubts about the safety of train travel in Spain, which boasts the world's second-largest high-speed network after China.

Unions called the February 9-11 strike, accusing the authorities of ignoring warnings about the safety of infrastructure and failing to invest enough in the network.

The movement affected thousands of passengers on Monday morning, but the Semaf train driver union announced a deal had been struck with the transport ministry, railway infrastructure manager Adif, state operator Renfe and the rail safety agency AESF.

"We have achieved a milestone in rail safety," a Semaf spokesman said, explaining that the 25-point deal addressed higher investment in infrastructure maintenance and staffing levels.

Shock hit the sector after a collision between two high-speed trains in the southern region of Andalusia on January 18 resulted in the death of 46 people – one of Europe's deadliest such disasters this century.

Two days later, a commuter train in the Barcelona region ploughed into the rubble of a collapsed wall, killing the driver and injuring dozens.

Renfe said in a statement that 11.6 percent of its staff failed to turn up for their morning shifts on Monday, but that minimum service requirements had been respected.

These included 73 percent of long-distance services and 65 percent of regional trains. On suburban networks, 75 percent of trains must run at peak hours, with half of the normal service provided during the rest of the day.

Delayed and cancelled trains disrupted Atocha in Madrid, Spain's busiest train station, as thousands of passengers crowded the platforms during the morning rush hour.

At Barcelona's main station Sants, fewer passengers were in the concourse than usual, with the strike following weeks of chaos on the north-eastern Catalonia's ageing commuter network, used by hundreds of thousands of people. (AFP)