A pair of teens were struck by the L train inside the tunnel of the Bushwick-Aberdeen station in Brooklyn on Thursday afternoon, according to police.
The two 14-year-olds were found unconscious on the rail bed when police arrived just before 2 p.m., cops said.
One of the victims had trauma to the body and was declared dead at the scene, they added.
The other boy was taken to Cohen Children’s Hospital, where he is in stable condition.
Mayor Adams was expected to hold a press conference at the scene.
Authorities have struggle to discouraged youth from subway surfing, a sometimes deadly trend fueled by social media.
Zackery Nazario, 15, was killed in February while subway surfing atop a train rumbling over the Williamsburg Bridge as his girlfriend watched in horror.
Another 15-year-old, Ka’Von Wooden, was killed in December. He was subway surfing on top of a train as it approached the Delancey St./Essex St. station on the Lower East Side when he fell under and hit the third rail.