It happened at around 7 p.m.
Police say two teenagers and an adult got into a fight on the train.
When they exited the train, the adult pulled out a knife and stabbed one of the teens on the platform, according to surveillance video obtained by police.
The 17-year-old was taken to the hospital in stable condition.
The search continues for the knife-wielding man who fled the scene.
MORE TOP STORIES: