They have them on the underground system in Tokyo. Carriages are painted pink. One time Mr.Sam got on with me by mistake and got some filthy looks. Once we realized we alighted at the next stop.
Back in the day railway carriages had separate compartments which held about 8 or 10 people.; once you got into a compartment you were stuck there until the train stopped so I can understand ladies wanting ladies-only compartments. With the current system of open carriages it seems unnecessary.
They have 'women and children' coaches on the Dubai metro too...again painted pink, but its actually a coach and a half, so very easy to sit in the wrong bit...like I did. Not a problem though. A young lady politely pointed out my error and I moved.