The Red Line Extension (RLE) is a proposed 2.3 billion dollar extension of Chicago’s “L” line to the city’s southern limits. Although plans to extend the line have been discussed over the last half-century, the RLE has only just entered into its “project development phase” and construction is not expected to begin until 2025. This thesis, utilizing interviews with city transit officials and community organizers, traces the history and present of the RLE as an “affective infrastructure.” In particular, focusing on the evolution of community and official representations of the RLE from the early 2000s to the present, I argue that the RLE serves as a contested site in which political imaginaries are continually remade through affectively invested histories and practices. Both residents’ and planners’ engagement with the RLE involves the deployment of claims regarding the relationship between the state, governance, and citizen. I conclude that analysis of the RLE necessitates that we understand the state as constituted, essentially, by affectively invested practices and representations.