People on the trains never looked at each other... they just seem to look down at the ground.  This picture is of a really empty train.  This isn't a particularly busy subway line (the Ginza Line), at least not when I tend to take it.  There have been times, though, when I felt like pretty much every part of my body was pressed up against the person next to me.  Luckily, I only had 2 stops.  It was about a 3 minute ride.