A man asked a subway conductor for directions on Saturday morning, then flicked cigarette ashes in her face, police said.
The union representing transit workers said the man also punched her in the shoulder. She suffered a bruise to her shoulder.
The conductor was driving a subway train in the Dekalb Avenue station in Brooklyn at about 7:30 a.m. when a man approached and asked her for directions, the NYPD said.
Then he threw his cigarette in her direction, police said.
The conductor, who has worked for the MTA for about five years, was placed on injury leave due to her shoulder, the union said.
The attacker fled, police said. No one has been arrested.