Not exactly the stunning super-speed routes you're looking for, but I did the Minato Railway in Ibaraki, near Hitachi-naka (In fact it includes the stop to service the Hitachi factory). It's a little low speed diesel line run by the Ibaraki Kotsu bus company. You'll see a recommendation for a Czech rail car from Trainzpedro, needed if you get the session.
I also did the Kobe Portliner, a New Transit guideway system which looks good with the German Desiros.
Do a search under my user name if you're interested.
There are no actual Shinkansen routes yet, but there is a TGV route that should be fine with the bullet trains.

Claude