At Chicago Magazine, tilting at a favorite windmill:

But accidents of history have split these lines among three different public agencies—none of which, traditionally, have bothered to tell you about the others on their maps or signage. That means that when you look at a map on a CTA train car, there are actually more than 70 rail stations in the city of Chicago that exist in real life—I promise—but mysteriously do not exist on that map.