BUENOS AIRES: Forty-nine people were killed and 461 treated in hospital after a packed commuter train slammed into the buffers and safety barriers at one of Buenos Aires's busiest railway stations.

The crash, the second-worst in Argentina's history, may have been caused by brake failure, the country's Transport Secretary, Juan Pablo Schiavi, told local media shortly after the crash on Wednesday morning. The train entered the station at 26km/h and probably hit the barriers at 20km/h, he said.