A woman with three small children in tow whacked a Queens subway motorman in the face with her bag when the worker tried to break up a fight she was having with another straphanger, cops said Saturday.

The 48-year-old motorman was trying to intervene in the argument around 8:40 p.m. Dec. 27 on the southbound Court Square G train platform when the woman suddenly smacked him with her handbag, chipping his tooth, police said.

He was taken to Mount Sinai Hospital-Queens, where he was also treated for a cut to his lip.

The assailant, believed to be about 35-years-old and 5-foot-6, remains at large. She was last seen wearing a dark grey hat, black waist-length jacket, grey tights and red sneakers. Cops say she was with three kids at the time.