Flags were flying at half mast at Port Credit Secondary School on Wednesday, as students mourned the death of their Grade 11 classmate Mamta Singh, who was hit and killed by a GO train Tuesday.

Singh, 17, was struck at about 4:30 p.m. near the Port Credit Station.

Students in the area told CTV Toronto that the place where Singh was struck is a commonly used short cut across the tracks.

Singh leaves behind a mother, father, sister, brother and extended family in Mississauga.

One of Singh's uncles spoke to CTV News, saying the family is devastated.

"She's a really beautiful girl, a really nice girl, always smiling, I've never seen her mad, or anything like that," said one family member.

Makeshift memorials were growing near the site of the collision and in the Port Credit station parking lot a short distance away.

"She was beautiful," said one classmate. "She had a really bright personality. Just talking to her would make you happy."

Students also said there should be a larger fence near the tracks where Singh was killed.

Meanwhile, police were reminding people of the dangers of walking on train tracks, saying the public must stay aware of fences and barriers around restricted areas.

Police are also searching for witnesses to the collision, which occurred as Singh was walking along the tracks with a friend.

Both girls were walking west, their backs to the oncoming train, and the windy day meant the girls didn't hear the train coming, police said.

One girl made it off the tracks safely, but Singh was hit and died of her injuries.

GO train service was suspended on the Lakeshore West line between Union Station and Port Credit station following the collision.

Police finished their investigation Tuesday evening but delays continued into the night along the western leg of the transit corridor.

Anyone who has information about the collision is asked to call Peel Regional Police major collision bureau at (905) 453-2121, ext. 3710, or Crime Stoppers anonymously at 1-800-222-TIPS (8477).

With files from CTV Toronto's John Musselman