Newton, (US) (AP): Two commuter trains collided and derailed during the evening rush hour outside Boston, trapping and killing the operator of one train and injuring several passengers, authorities said.

The crash came on wednesday just hours after an elevated train derailed in Chicago, sending several people to hospitals in a wreck that officials quickly blamed on operator error.

Investigators did not know what caused the Boston wreck, which killed a woman and injured about 10 passengers in an above-ground accident near a station in suburban Newton.

The operator's body was still trapped in the wreckage late Wednesday, said a firefighter at the scene who spoke anonymously because he was not authorized to do so publicly.

The two-car train she was operating slammed into the back of another two-car train approaching Woodland Station, said Joe Pesaturo, a spokesman for the Massachusetts Bay Transportation Authority.

"The first one was stopped at a red signal and was ready to proceed to the station when it was struck," he said.

The hospital had eight train-wreck patients, none with serious injuries, said spokesman Brian O'Dea.

The train operator's father, Terry Jones, identified her as 24-year-old Terrese Edmonds, The Boston Globe reported. Firefighters struggled to free her body from the tangled wreckage.

Federal investigators were on their way to the crash site, said Peter Knudson, a spokesman for the National Transportation Safety Board.

In Chicago, authorities said a train operator apparently made two key errors in quick succession to cause a derailment that left passengers perched more than 6 meters above the ground and sent several to hospitals.