The line gets really blurry in some places in Tokyo. Asakusa (one of "my" lines!) line, is definitely a subway inside central Tokyo, but you can stay on the sa

The line gets really blurry in some places in Tokyo. Asakusa (one of "my" lines!) line, is definitely a subway inside central Tokyo, but you can stay on the same physical train going all the way from Narita to Haneda (think RER in Paris?) — I think it would be qualified as "light rail" anywhere else in the world.