BELMONT, Mass. -- Investigators are looking into whether a popular shortcut may be to blame after a Belmont High School student was struck and killed by a train.

Police said the unidentified 18-year-old girl was struck by a Fitchburg line commuter train just before 1 p.m.

Police said it appears the high school senior crawled through a hole in a fence near the school, employing a commonly-used shortcut that may have ended up cutting her young life short.

"There's been a hole in that fence for awhile. It gets patched up but it, overtime, the fence is old so more holes start and they get bigger and bigger," one student said.

Officers said there have been accidents in the area before. Commuter trains can reach speeds of up to 60 mph in the stretch where the girl was hit.

The Belmont schools Superintendent George Entwistle called it a sad day for the school system and grief counselors were scheduled to be on hand at the high school Friday.

A note on the high school's Web site warns students that anyone found on the tracks is subject to arrest on trespassing charges.