Josh Barro provide examples galore of why the answer to that question isn't always yes—where costly rail investment has been to the detriment of existing transit. His column targets proposed projects, such as New York's LaGuardia Airport AirTrain.
Feb 11, 2015 New York Times - The Upshot
Yonah Freemark writes of the value of infill stations—new transit stations built on existing lines—for increasing transit ridership. Somerville, outside of Boston, will provide the latest example when it opens a station on the Orange Line next week.
Aug 29, 2014 the transport politic
In another example of Los Angeles slowly unraveling itself from prior legislation that hinder its transit goals, Governor Jerry Brown signed a bill that will allow light rail construction in the San Fernando Valley.
Jul 13, 2014 Los Angeles Times