Sources: LI teen killed by train ID'd as Liam Armstrong

The Nesconset teen hit by a Manhattan subway train Tuesday night was following his friend across the tracks and died before he could cap off his 18th birthday celebration, New York City police and a friend said Wednesday.

Liam Armstrong and two friends, on their way to Greenwich Village, had mistakenly boarded an uptown train near Central Park and tried to switch to a downtown train at the West 79th and Broadway station, police said.

One friend crossed four tracks to the downtown platform, and when Armstrong followed, he was hit by a northbound No. 2 train, police said.

Transit cops found Armstrong's backpack on the tracks, a broken bottle of rum inside, law enforcement sources said. Police said Armstrong was pronounced dead at the scene.

Wednesday, Armstrong's friends and community tried to comfort his family and each other as they realized one of their own wouldn't be graduating from Smithtown High School East in June.

"He'll be 18 forever," said his friend Alex DiPenta, 18, of Smithtown. "He always had a positive outlook on everything and he was never angry."

On spring break this week, hundreds of students swarmed the high school's athletic fields Wednesday night, holding a candlelight vigil to honor Armstrong.

Those who knew him said he was on the lacrosse team until this year and loved soccer.

He worked at the Wendy's in St. James and had enlisted in the Marine Corps Feb. 26 in Fort Hamilton, Brooklyn, said a Marine spokesman.

Lauren Laurenti, a senior at Smithtown East, said Armstrong was a popular student and a respected athlete whose likability allowed him to transcend any campus clique.

As president of the school yearbook, she plans to devote an entire page to Armstrong. After making that announcement in social media, Laurenti was flooded with hundreds of messages from students, in shock but eager to offer photos.

"It's horrible," said Laurenti, 18. "If we were in school, it would be a disaster."

In a statement Wednesday, Smithtown Central School District superintendent Anthony J. Annunziato described Armstrong as "a popular student among his peers and the high school staff," adding: "He was a vibrant young man who will be missed by all who knew him. Our heartfelt thoughts and prayers go out to his family."

The teen's family did not want to comment. Wednesday, a Suffolk police car was stationed outside the home. His father is a Nassau police officer. A Newsday database of Nassau police salaries lists the teen's father as Christopher H. Armstrong, a detective sergeant with the department.

On his Facebook page, Liam Armstrong listed himself as a projected 2013 graduate of Smithtown East. Contributors to the Twitter feed #StayStrongSmithtown expressed their condolences and grief.

One student wrote: "Such a great kid. RIP Liam, forever in our hearts. Love you dude." Another wrote: "My heart is seriously in my stomach. I can't think straight, my thoughts and prayers to everyone."

The mother of one of Armstrong's close friends said the teen made mistakes Tuesday but noted a great side to him, shoveling the 25 inches of snow around her house in last month's storm.

"The whole town is very upset," said Rosemarie Wecker of Nesconset, whose son Brian was a close friend. "He was a good kid, he comes from a good family and he's going to be so missed."

She said she and others will try to work with the school PTA, restaurants and local groups to take care of meals, flowers and "whatever we can do" for the Armstrongs.

Armstrong, the oldest of the family's four children, had left with friends from the Long Island Rail Road station in Ronkonkoma at 1:10 p.m., arriving at Penn Station at 2:45 p.m., police said. They ate at a McDonald's, went to Central Park and then decided to head to the Village via the subway at 59th Street -- but boarded the uptown No. 1 train, police said.

One of Armstrong's friends made it across and his other friend stayed behind on the northbound platform.

DiPenta said he was sleeping when Armstrong left a message asking him to join him in the city for his birthday.

By the time he awoke, Armstrong had left, and Wednesday, pangs of regret stung DiPenta.

"I was supposed to be there," he said. "I think about that all the time now. I could have maybe talked him out of what he did."