First time I've been to Tokyo several years back and the train networks is what amused me most about Tokyo and Japan in general. I've tried most of the trains in Japan using the heavily discounted tourist Japan Rail Pass (not available for local) including the the Sunrise train for overnight or sleeper train [1]. The private cabin of sleeper train is not covered by the Japan Rail Pass only the open cabin Nobi-Nobi seats but it's really worth it because the hotels in Japan are very expensive. The pass also excludes the fastest Shinkansen Nozomi trains.

For travelling with train (or any public transports in Japan) you can just use Google Maps and it's really Google Maps in steroid in Japan. You will know accurately in real-time all the trains and buses, and their respective arrival/departure times and even their rare occasional delays. All these real-time information are feasible because Japan contracted Hitachi company to provide the info trough the open API for other developers to access and it's very accurate. With Google Maps capabilities the integration with the real-time is just mind blowing to be experienced by any tourist, especially the Japan trains networks extreme timeliness.

I really wish someone come up with a VR or meta based game for tourist in Japan for buying souvenirs. This type of game was my favourite towards the end of 80s for shopping in London using the London Tube trains back in the Windows 2 time. It's only text based game and not real-time but it was an awesome gaming experiences nonetheless. Somehow I've forgotten the name of the game, but I think with all the 3D and real-time information available it will be a blast for the modern incarnation of the tourist souvenirs game to be based in Tokyo, or London.