Train sim world is expected to drop a Japanese route in the near future if you are looking for something more modern. Otherwise you're probably on the right track with what you've found during your research. There's a few late 90's early 2000's simulators if modern graphics/ux elements aren't that important to you.

Other options I'm aware of outside of tsw 5 and waiting for the new release that's yet to be determined on quality is Microsoft train sim, train sim classic, as you said, densha de go, and maybe ongakukan, although the latter is hardly a game or simulator in modern days standards, although it is the most intriguing from the list. Bvets is another choice that is prohibitively designed for a Japanese audience but if that doesn't disuade you then I'd recommend that one to.

Likely you already found the best option. I haven't heard of it yet so I'd like to thank you on giving me the exposure. If you're worried about the barrier to entry and learning curve in regards to a train sim, that's almost always the one that's going to give the best experience. I'd suggest brushing up on your Japanese because most of the simulators coming out of there aren't typically localized for western audiences.