I guess that in most if not all cities, it depends on the alternatives, which should drive the demand for living next to transit that takes you where you want to go. If there is no particular demand for housing next to a rail line that takes you into downtown, because the alternatives are easy or cheap, then I suspect that it would not necessarily be more expensive to live there. Consider the alternatives in Houston for someone who works downtown: 1) Live outside downtown and take MetroRail to work. 2) Live downtown. 3) Live outside downtown and take a bus to work. 4) Live outside downtown and drive to work. The demand for (1) is going to depend on the cost, availability and ease of (2), (3) and (4).