I was browsing thru pages and pages of apple apps in the travel section and came across "trains.jp". It's Tokyo train route information (in English) covering over 1300 stations and 110 lines. There's "trains.jp" (orange colour) and "trains.jp NET" (red colour) Same developer but the orange trains.jp does not require an internet connection while the other version does. Both apps are free. Tokyo is huge and at some point you will need to take the metro.