At least 49 people were killed Wednesday when a packed commuter train slammed into a retaining wall at a railway terminus here during rush hour, a police spokesman said.

“Unfortunately, we must report that there are 49 dead in the accident,” police spokesman Nestor Rodriguez told a news conference.

At least 550 people were injured in the crash, which witnesses said occurred after the train’s breaks failed as it was arriving at a station on the western outskirts of Buenos Aires.

The accident occurred just five months after a morning rush hour crash in the Argentine capital involving two trains and a bus killed 11 people.