I remember meeting a lot of people by just talking to them in the subway during y daily commute. That happened both in France and Japan. Nowadays with phones it happens a lot less..
I had the same experience of meeting people in the same way in Shanghai in 2004 (bus and subway). And before that, in France,the bus line I took near my university was filled with students.
Really struggling to imagine people talking on the subway during their morning commute in Japan!! Culture changes.