MIDTOWN, NY — No good deed goes unpunished. A stranger bashed a woman in the head with a metal pipe when she tried to stop a fight between two subway straphangers, police said.

The 28-year-old woman was on the north-bound platform for the N, Q and R lines at the 34th Street-Herald Square station at 7:15 a.m. Wednesday, when the woman tried to break up an argument between two feuding commuters, authorities said.

Instead, one of the men directed his rage at the woman and smashed her in the head with a metal pipe, causing several cuts, police said.