A woman randomly stabbed a straphanger in the arm onboard a Queens train Tuesday morning, cops said. 

The 56-year-old victim was on board a Manhattan-bound A train at the Broad Channel station around 8:20 a.m. when a woman, believed to be homeless, suddenly stabbed him, police said. 

The attacker bolted from the train and fled the station, cops said. 

The victim was taken to St. John’s Episcopal Hospital, where cops say he was conscious and alert. 

Police said the attacker, who was wearing red clothing, was still on the loose later in the day.

The incident comes amid a recent surge in violence in the city’s subway system.