BOSTON (CBS) – Green Line service has returned to normal on Sunday, a day after 10 people were hospitalized following a train derailment near the Fenway MBTA station.

Severe delays were reported Saturday following the derailment. Riders were asked to find alternate transportation.

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It happened just before 11 a.m. Boston EMS said 11 people were injured and 10 were taken to area hospital with injuries ranging in severity.

The train operator was among those taken to the hospital. None of the injuries are believed to be life-threatening.

“We had a total of 10 patients. Nine were transported to area hospitals … varying in severity of injuries, but overall, all the patients that we saw today will have a positive outcome,” said Steve McHugh, of Boston EMS.

Service resumed Sunday after a “robust testing” of tracks and signals in the area. “Preliminary findings indicate the cause of the incident was not a mechanical or infrastructure issue, though the confirmed cause of this incident continues to be under investigation and requires thoroughness, focus, and time,” the MBTA said in a statement Sunday.

Passengers evacuated following a train derailment in Boston. (Image Credit: Bryan Marden)

There were 150 people on the train that derailed and 500 riders on the train behind it.

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“A lot of people fell down, yes,” said Ricky Mejia, who was on his way to work. “Some people were bleeding.”

Passengers who were evacuated from the train walked through the tunnel and onto Park Drive.

“When we arrived on the scene, we found that the train was about 400 yards in the tunnel … that was derailed. We had some people walking out at the time. We had additional resources to help us with the people that needed help to get out of the train,” said Brian Atkins, of Boston Fire.

Some damage was done to the train following the incident.

Firefighters remove a patient from the tunnel near Fenway station following a train derailment. (Image Credit: Boston Fire Department)

One witness said it was an intense scene.

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“About three or four people on stretchers. One young lady, she had some blood – nothing major but some blood on her face,” said Antonio Carreiro, who was working nearby. “It was shocking, especially today with everything going on the baseball game and the parade.”