Earlier quoted context omitted.
> All I could think was that he put on that intervention for us few foreigners Nah. In Japanese culture, it's simply considered rude to be loud in trains.
Still. I've never seen a conductor yell at anyone for being loud, especially in the cities. Maybe it happens in the inaka...
Anecdotally I've heard that social censure is far more common and ruthless in the women's-only cars.