As for maps: there certainly were in print-both in Japanese of course-the country does seem to have also a load of dedicated railfans, and incidentally also in /en/. As I am now not @home, cannot give data, also dont know if still available-but changes in Japan are not that many. Due to its special tri-languages system, Japan does also seem to stick longer and more as in the west to printed books/maps etc. There is also a fairly big Railway/fan Club, that also issues/prints a lot of such things. I remember also a complete tramwaysystems atlas.
The LRTA, based in UK, also once issued 3 volumes on the many private railways+local systems-but must have been pre 2000. You may perhaps find some 2nd hand ones.
ONline; dr google via openrailwaymaps/Japan leads into wiki pages that do seem to show also various maps etc.-these load vary slowly to where I am now-so check yourself. What I remember is also that one needs to have a certain knowledge as to how railways and its many private companies and geography work over there, otherwise you will get lost in the enormous amount of data.
Those atlases mentioned also had broad fleet listings-not very specific, but I am hardly interested in that, so leave it to others for more.
