JR East Japan will institute a complete smoking ban at all 226 metropolitan area stations (such as those on the Chuo, Keihin Tohoku and Yamanote Line) beginning in April 2009.

The ban applies to any smoking out in the open which is now allowed at the ends of the platform or at designated "smoking stands".  These will be eliminated.  Stations which have enclosed smoking rooms installed either on the platform or in the station concourse can continued to be used.

The measure is being instituted due to the growing concern of secondhand smoke in addition to more non-smokers.  Yes, it is hard to believe that there is a growing non-smoker movement but the smoking problem at train stations in the past was worse where JR developed a cigarette butt sweeper (video from the late 90's) to vacuum up the stuff from the tracks.

JR East is finally following the lead of several private railway operators which completely prohibited smoking in their subway stations several years ago.