Almost all Japanese Model Trains are able to run on 16.5mm track(HO, OO Scale) or 9mm track(N scale) but its standard is different from other regions like Europa or the U,S because the width of real track in "Traditional Line" is 1,067mm.

Furthermore, in so far as Shinkansen(Bullet Train), it  has 1,635mm track(standard gauge) in the real so scales are 1/87, 16.5mm in HO and 1/160, 9mm in N scale.

In 1930's, it's the dawning of Japanese model train, makers didn't supply many types of model trains so user had to make stuffs by their own.

In that process, modelers started making those in 1/80 Scale to put on 16.5mm Track and those wouldn't be looked strange when they connected with Heavy Weight Coach in the U.S or Corridor Coach in the U,K.

For that reason, the standard was fixed in 1/80 Scale, 16.5mm.