Tokyo's commuter system may resort to more single-sex cars to cut down on groping.

A record 22-hundred groping complaints were filed last year, many by teenage girls wearing mini-skirted school uniforms. There were almost 19-hundred arrests.

Suspects ranged in age from 14 to 80, with about one-third being men in their 30s. If convicted, they can get up to seven years in prison.

Tokyo's (search) subways and trains are jammed during rush hour, especially in the morning. Groping (search) has been a problem for over 40 years.

Some train operators introduced "women only" cars, but their number and service hours are limited.

Police plan to increase patrols on trains and platforms to discourage would-be gropers.