I know little of Dallas or the nature of its rail system and the neighborhoods it travels through, but
it is the case in most American cities that such systems should be built in order to change car-centric development patterns (if you're going to build them). Even in my urban hellhole the extensive
commuter rail system is underutilized (though at post-1980 record levels) because in many areas zoning and land use decisions have prevented transit-oriented development around stations.