A two-level train slammed into another that had stopped between stations during the morning commute today.
Firefighters and police are pulling passengers from the wreckage, and helicopters are taking people to emergency rooms.
Train operator spokesman Pablo Gunning says there are "various fatalities" though has not specified how many Union leader Ruben Sobrero told reporters at the scene that the two-level train had been out of service for six months before it was brought back online shortly before the acccident. Gunning said the engine had new brakes installed.
The accident happened on the same Sarmiento line that the government took over after another wreck blamed on brake failures caused 51 deaths and 700 injuries last year.