Train tracks going through a city are at the same time part of the city and not part of the city: a city is build for people, but you can not live there, you are not even allowed there. Same goes for high ways, sub-way tunnels and garbage dumps. I sometimes use these places as symbols for the border lands of our society.
A border separates and also creates order: these people belong over there and we live over here, and -according to some-that is how it is supposed to be. Certain thinkers have pointed out that Europe has the tendency to create places where that what does not fit in society will be banished to, like the terminally ill, the mentally unstable, the disabled, those with grotesque appearances and the criminal minds. These are the places where that what is deemed unclean, unholy, non-rational and unacceptable is expelled to, surrounded by a set of boundaries of their own.
Most of the times people are put there against their will. But there are also people who choose to step outside of the grandeur Europe/the western world has to offer, and they try to create their own place of refuge with their own rules.