The train station was a place of mobility--but also a place where certain people were watched and stopped. From their beginning as humble buildings that happened to be at the end of a rail line to giant edifices that seemed as public as city hall, large urban train stations have been the American city's ceremonial gate. This talk discusses the evolution of so-called unions stations and the social gravity they exerted on American cities in the nineteenth century. Zach Nowak argues that these large urban stations sat in the liminal space between public and private, and gave municipal governments a spatial multiplier effect to exert their power. His talk focuses on his main case study, St. Louis' Union Depot, but also incorporates material found at the Newberry Library.