The Washington Metropolitan area has been growing rapidly and experiencing gentrification since the 1980s. Contemporaneously, a light rail corridor in the inner suburbs was planned and is currently being constructed. This light rail, Maryland’s Purple Line, travels through dense urban areas, post-war era suburbs, and through a series of dense low-income immigrant gateway neighborhoods. Through a case study of the Purple Line during the construction phase, this paper examines the costs and benefits of the modern paradigm of transit-oriented development. Qualitative evidence suggests that the benefits of the line may be imbalanced against its costs in the short run, especially with respect to housing stability and affordability, displacement, and neighborhood change. Furthermore, this paper argues that displacement due to transit investment can occur prior to the opening of new transit lines. In light of this, the tenuous political coalitions that support construction of light rail will have to adjust to be more inclusive of equity, vulnerable populations, and provision of affordable housing.