On a recent Wednesday evening, with hours of summer daylight left, dozens of people were out enjoying the Bloomingdale line, a dormant railroad right-of-way that runs 2.7 miles across the northwest side, 15 feet above its namesake street. They strolled, they jogged, they cycled, and they exercised their dogs, oblivious not only to the carpet of glass, weeds, and garbage but to the law: the Bloomingdale line is private property, and everyone on it was trespassing.

Of course not all trespassers are created equal. “During the day joggers and bicyclists are fine,” says Bucktown resident Joan Fox, whose house abuts the line. “But when the sun goes down the violence goes up.”