The aim of this chapter is to develop an analytically meaningful framework to analyze ‘suburban infrastructure’ by paying concerted attention to how infrastructures relate to the production and experience of dynamic and highly variegated suburban environments. My approach is built around two conceptual triads: the first unpacks the modalities of infrastructures as they exist in, for, and of suburbs (broadly understood as the landscapes of extended urbanization); the second discloses the political economic processes (suburbanization), lived experience (suburbanism), and dynamics of mediation internalized by particular suburban infrastructures. I am not concerned with the tasks of ensuring definitional rigor or bounding what does and does not constitute ‘suburban infrastructure’. Rather, I seek to identify adaptable conceptual and methodological innovations from the distinct relations between the suburban and any number of hard and soft infrastructures facilitating social processes and relations across space. I concretize this argument by briefly unpacking the politics of rail infrastructure in the Chicago region, focusing on the changing modalities of suburban infrastructure surrounding the 2007-2009 acquisition of the Elgin, Joliet and Eastern Railroad by the Canadian National Railway.