I know its a beta and free, so I will review it accordingly. I think its a really good start. Auto completes the station names and tells you how to get from one to the other. Simple, clean and elegant.
If you added the times for departing trains and estimated arrival, I would gladly pay $.99 for this app.
If you added destination oriented and complex routing its easily a $4.99-$7.99 app for me. So, allow me to simply start with a destination. Then you use the GPS to locate me and intelligently pick the closest station that will get me there. Allow me to choose fastest route vs. simpliest route. Then build my route: path to station, then train + subway to destination.
Finally, if you added complex scheduling its easily a $9.99-$12.99 app. So, real-time schedule information, delay warnings, total travel time (i.e. time on this train+time waiting for next train+time on next train*delays), push alerts for schedule changes/delays on saved "my routes".
Thanks for the work and keep it up. I think many of us travelling to Japan that are used to other apps in other counties (look at apps for London tubes for example) would be happy to pay for a quality train app for Japan.
MozeMac about trains.jp, v0.1.1