Did you know that in some trains there are cars for exclusive use of women? Not always, of course.
In the example above, the train that goes to Tokyo station has the first car reserved for women on morning time (when the train is insanely crowded).
It also says that young boys (until elementary school), and handicapped people and their accompanying people can also use this car.
This is to avoid “troublesome situations” caused by “troublesome people”. It also prevents some “awkward accidents” that might happen in an overcrowded train.