A packed train slammed into a barrier at a Buenos Aires station today, killing 49 people and injuring hundreds of morning commuters.
Federal Police Commissioner Nestor Rodriguez said the dead include 48 adults and one child.
It is Argentina's highest death toll from a train accident since 1970, when 200 were killed in a train collision.
Earlier, Alberto Crescenti, the city's emergency medical director, said at least 550 people were injured and that 30 people remained trapped inside the first car, where rescuers carved open the roof and set up a pulley system to pull them out.
The commuter train came in too fast and hit the barrier at the end of the platform at about 12mph, smashing the front of the engine and crunching the leading cars behind it, Argentina's transportation secretary told reporters at the station.
Most damaged was the first car, where passengers make space for bicycles. Survivors told a TV channel that many people were injured in a jumble of metal and glass.
Passengers said windows exploded as the tops of train cars separated from their floors.
The trains are usually packed with people standing between the seats, and many were thrown into each other and to the floor by the force of the hard stop.
Many people suffered bruises, and many with lesser injuries were waiting for attention on the Once station's platforms as helicopters and more than a dozen ambulances took the most seriously injured to nearby hospitals.
"This machine left the shop yesterday and the brakes worked well. From what we know, it braked without problems at previous stations. At this point I don't want to speculate about the causes," said Ruben Sobrero, a union chief.