Trains are great if the city can be built around them, but otherwise its a money drain. The DART system here in Dallas has good ridership and gets 22c revenue for every $1 spent. Even if the ridership raises to fuller capacity they may get revenue of 40-50c to every $1 spent.
I heard a story about the highrise developments in downtown Dallas; that young people and empty nesters - who work for TI and other suburban companies - live downtown and use Dart to get to work, instead of living in the burbs and going downtown to work. This, Dart trains, is part of the reason we have 19 cranes building new housing and that, taxes on construction and homes (starting @ $400,000), helps to offset that per person cost you mention.