Investments in new transportation infrastructure hold the potential to transform the urban socioeconomic landscape by reshaping accessibility and by encouraging new developments around these investments. This chapter outlines the theoretical arguments for why and how transport, specifically rail transit, is expected to impact the socioeconomic composition of neighborhoods and reviews the relevant empirical literature on the subject. Neighborhood socioeconomic change, including gentrification, can be viewed as the product of shifts in residential sorting of residents reacting to the placement of a new (transit) amenity which may place increased demand for living in a particular area. This demand may place an upward pressure on nearby housing values and rents, affecting the socioeconomic composition of those willing and able to afford these price premiums, thus spurring or accelerating gentrification. Rising land values may also lead to the disproportionate exit of lower-income residents unable to keep up with elevated rents or property taxes. To date, the empirical evidence on the link between transport investments and gentrification has mixed findings, very often underscoring the importance of local context in directing a neighborhood's path. Research has overwhelmingly centered on aggregate neighborhood changes, but several studies have recently emerged that center on individual movements that give rise to these neighborhood-scale outcomes.