A packed commuter train plowed into the buffers at a Buenos Aires station during yesterday morning rush hour, killing 49 people and injuring more than 600 in Argentina's worst rail accident in more than 30 years, officials said.

Passengers told of chaos and panic as the impact of the collision propelled the second train car into the first carriage, trapping dozens of people as others looked on from the busy platforms at the central Once station.

Officials said faulty brakes were suspected of causing the accident.

"All of a sudden we felt an explosion and we literally flew through the air ... there were lots of people thrown to the floor, injured, bloodied," a passenger wearing a neckbrace told local television.