A 61-year-old straphanger was stabbed in the stomach on board a Bronx train — blocks from Yankee Stadium — Friday afternoon, cops said.

The victim was riding a southbound No. 4 train just after 3 p.m. when another man knifed him once at the 167th Street station near River Avenue in Highbridge, police said. 

Someone flagged down NYPD cops standing on a post, alerting them of the midday attack, cops said. 

The wounded man was taken to Lincoln Medical Center, where he was listed in stable condition.

The suspected stabber, described as a man wearing a black jacket, fled the scene and hadn’t been caught by the early evening. 

The motive for the violence remains under investigation.