The teen fell off the train and onto the tracks at the Baychester Avenue subway station.
On Tuesday, officials said his condition stabilized after suffering facial and body injuries, but he is still fighting for his life.
A fellow 17-year-old subway surfer was taken into custody at the subway station. He was charged with reckless endangerment and trespass.
A third teen is still being sought.
NYPD Transit Chief Joseph Gulotta said the No. 7 subway line is the most dangerous. Because of the wide open space, it attracts the most subway surfers.
"The 7 line, that's like ground zero for this, if you ever saw 'Spider-Man, Homebound,' the last scene is him riding the 7 train," Gulotta said.
He said they are flying drones every day and they have been a "game changer" as they search for subway surfers.
Officials say 79 people have been arrested for subway surfing this year, compared to 88 that were arrested by this time last year.
Two people have died in subway surfing incidents so far this year after six died last year.
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