Though Tokyo is the most populated city, its railway networks are also world's most complicated ones. So, each train's population density should be similar to that of world's megacities.
The difference is that there are many trains which skip many stations in Japan.
Those trains keep their doors closed so long between stations that there would be condensed water on windows to emphasize miserableness of crowded trains.
Odakyu Line, the photographed railway on the article, is under construction of quadruple tracks to solve the extreme crowd of those trains.
A ride in hell? An up-close look at real life in megacities
http://edition.cnn.com/2016/10/11/arts/michael-wolf-photography/
