Innsbruckblue said:
I lived in Germany for 12 years and never once came across a free underground system. Which cities do you mean?
Haha, I think I probably jibbed it then.
But I'm pretty sure I didn't have to pay on the Hamburg underground, and when I went to Berlin, I remember glimpsing some machines that might have those 'self-service' machines, but I wasn't there long enough to inspect them: I just hopped on the train.