All three women survived slash wounds to their legs, after police say a man with a white T-shirt with a blank stare attacked them from behind unprovoked.
Charges against the suspect were expected to be announced at a press conference on Tuesday afternoon.
One of the victims, 19-year-old Bianchelli Diplan, was attacked while leaving the 4 train at 86th Street.
"I started up the steps and then I felt something in the back of my leg. So like, I like, hold on to it. And I saw there was blood. So I turned around I saw him and, like, he just stared at me and I was crying, crying. And he just walked away," Diplan said.
Police believe the same man also slashed a 48-year-old woman at that station, and rode the train down to the Brooklyn Bridge Station where he slashed a 26-year old woman. None of the women knew each other and the attacker said nothing.
Diplan says she would like to see even more police officers, like there were at 86th Street on Monday. She is urging fellow riders to be on the lookout on the subway, because the suspect is still out there.
"Just to be safe, be aware of your surroundings. Because this could happen to anybody," she added.
Subway crime was down 13% last month but that may be of little consolation to riders after the violent weekend.