The commuter train was travelling at nearly 100 kilometers an hour when it slammed into the rear end of an empty six-car train manoeuvring slowly from one track to another on Thursday, the Supervia company that runs the train said.

Some passengers aboard the commuter train had to be freed by rescue workers using blowtorches to cut through the twisted wreckage.

The collision, about 200 meters from a station on Rio's poor north side, killed eight people, said Pedro Machado, commander-general of the Rio de Janeiro Fire Department.

"We have to use blowtorches to open the sides of the train cars to reach the people," Machado said in a televised interview.

"But now we're positive that there are no more fatal victims."

Brazil's government-run news service said 84 people were injured, while the a Web site said the number reached 101.

Most suffered light injuries, the reports said.

Authorities later confirmed that all the passengers had been freed from the wreckage.

Joao Gouveia, Supervia's operational director, said the number of casualties was not higher because the eight-car commuter train left the downtown Central station before the rush-hour crush that routinely packs the trains wall-to-wall on business days. - DDNEWS