In dealing with the examples of ill-behaved humanity that still plague the city’s subway today, the powers that be in 1909 thought they were doing the ladies a favor when they suggested the addition of women-only subway cars, according to Ephemeral New York. Called “suffragette” cars (though women didn’t win the right to vote in New York until 1917) they were introduced on trains of the Hudson Tubes running from Manhattan to Hoboken (today’s PATH line). In trial runs, the last car in each train was reserved for women. Officials of the five-year-old IRT line began considering the idea–thought to be a success in its earliest trials–for the New York City subway.
There were once women-only NYC subway cars
They were called "suffragette" cars.