A third teenage suspect has been arrested in connection with a New Year’s Day gang assault in a Bronx subway station that left a good Samaritan dead when he was struck by a train, NYPD said.

Noel Rosado, 19, was taken into custody on Friday afternoon. He’s charged with murder, manslaughter, robbery, gang assault and assault, police said.

In January, two other teenage suspects — a 17-year-old and 16-year-old male — were also arrested and issued the same charges.

The three were part of a group that allegedly approached a 38-year-old man around 2:40 a.m. inside the Fordham Road subway station and pulled out a knife before they physically assaulted him, police said.

During the struggle, the victim tumbled onto the tracks as a train approached. In that moment, Huston Roland, 36, selflessly jumped into the roadbed and attempted to rescue the man.

The oncoming train struck Roland, killing him. The 38-year-old victim, who was not identified by police, was not struck by the train and survived.

He was taken to an area hospital for a fractured arm, where he was treated and released. 

Photos from the subway station show about a dozen people who appear to be in their teens and early 20s who fled the station, cops said.