Old story, it happened more than 6 month ago and I do not know why I have not written it yet...
My wife's sister lives in New-Zealand as her husband is a guy from that country. They live in Auckland, which is far-far from Budapest. We were there 4 years ago and went there in the end of December, 2010 also. We had to spare some money for the airplane tickets, but my wife wanted to see her sister's kid finally. So we looked for the most cheapest tickets on the internet. The best offer was a quite long trip: Budapest - Frankfurt - Tokyo - Christchurch - Auckland. 40 hours, the waiting time in Narita was 10 hours. Of course we went out to the city.
One of my Hungarian friend lives and works in Tokyo. He was so kind that came to the airport and brought us into the city. I could finally travel on the Yamanote line, see real Shinkansens, buy some model train in a local hobby store.
I made hundreds of photos about that 5 hours while we were in the city, you can see them here:
http://www.vonatmagazin.hu/2011/01/5-oranyi-tokio/Text is in Hungarian (you can translate it with Google for example), I think there is no new information in it for you about Japanese railway, this is the reason why I did not translated it (and because of my poor English and little of time). I just would like to show you some photos of mine.
The biggest experience of these 5 hours was that I have to go back and spend much more time in Tokyo or in Japan. Maybe some years later.