Trains are ubiquitous in and around Chicago. The railroads and city grew symbiotically, and no one — particularly along Lake Michigan’s South Shore — is immune to their presence, both in nostalgia-tinged memory and while facing the challenge of daily navigation. But the railroads also occupy a “parallel universe,” in Geoffrey Baer’s description, a network that transports people, products and commodities at a scale and complexity often unseen and underestimated.