It happened just before 1:00 a.m. at the Broad Street Line platform below Broad and Locust streets.
Police say a 19-year-old male was shot twice in the back and stabbed in the head. He is listed in critical condition.
An 18-year-old was shot in the foot. He tried to walk away but collapsed near Broad and Walnut streets. He is listed in stable condition.
The second victim told police he was walking down the concourse to catch the trolley, when he heard several gunshots behind him.
Investigators are still unsure what sparked the attack.
No arrests have been made.