Cities are endowed with and accumulate natural and constructed assets based on their unique histories, which in turn define the choice set of the present. But, common practice is that current behavior can be described without reference to past circumstances. This work departs from that practice by examining the effects of historical urban rail on current residential location and travel behavior, from the era of horsecars and streetcars to the present in Boston. It uses aggregate spatial data, with controls for possible endogeneity over these long time frames to explore the hysteretical effects of past access to rail—the extent to which the urban system retains the impacts of rail even when it no longer exists. Findings: Current density and travel behavior are measurably influenced by past access to rail. These findings are robust to a series of alternate causal, functional, and spatial specifications. The built environment and demographic patterns are found to be the strongest mechanisms for these persistent effects. Past access to rail has shaped the city, and that shape has, in turn, affected travel behavior. For density and auto ownership there is an additional measurable effect of past access unexplained by the built environment or demographic patterns. This legacy is plausibly explained by cultural effects—mnemonics—due to personal history or behavioral norms. Takeaway for practice: This research shows that past rail access continues to reverberate in current residential location and travel behavior. These findings of quasi-irreversability add to an understanding of the long-term impacts of rail infrastructure, and imply a need to consider how policy decisions will influence the city's future choice set.