By Beth Germano

BOSTON (CBS) – It’s a tragedy that has hit Boston University just a few days into the school year.

The body of a 17-year-old freshman student from China was found on the Commuter Rail tracks beneath the Mass. Turnpike near campus late Tuesday night. Investigators are trying to figure out why he was crossing the tracks when he was struck by a train.

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“The preliminary investigation suggests this is a horrendous, tragic accident,” said Transit Police Supt. Richard Sullivan.

The MBTA commuter rail train was stopped for 3 hours for the death investigation in Allston Wednesday morning. (WBZ-TV)

The MBTA commuter rail train was stopped for 3 hours for the death investigation in Allston Wednesday morning. (WBZ-TV)

It was witnessed by students from their dorm rooms who looked out and knew something was wrong. “I saw dozens of detectives on the tracks with flashlights and I saw the body sprawled out,” said junior Rachel Small.

Officials say the student was likely hit by a train whose conductor didn’t realize it and continued on. The body was then discovered by a rail worker who warned the last train coming out of South Station on the Worcester line to slow down and stop.

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“A couple of minutes went by and the explanation was medical emergency, then more time passed,” said passenger Gary Barbin.

With detectives on scene more than 30 passengers were then detained for three hours before their train was allowed to move. “We were wondering why we were not getting alternate transportation looking at ladies, children and young adults,” said Barbin.

Transit police say they are investigating why the train was held for so long and apologizing to the passengers.

The name of the victim has not yet been released while the victim’s family in China is notified. Police are also reviewing footage to see if they can determine which train came in contact with him.

“We were excited for the first day of classes and then we went to bed with these images and thoughts, it was really tough,” said Small.

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WBZ NewsRadio 1030’s Bernice Corpuz reports

Beth Germano