The national transportation policy process disfavors transit projects in a lot of ridiculous ways. For a sense of how discouraging the pure, bureaucratic hassle is, read this article:
The FTA uses an elaborate set of criteria to decide which projects to fund. When I asked my former classmate and transportation wonk Matt Johnson to summarize the New Starts criteria for me last year, he sent me a 4,563 word email describing the seven criteria (not including sub-criteria) used to evaluate projects. Unfortunately the criteria are changed slightly each year so his email is now obsolete. The criteria range from the vaguely objective to the totally subjective (last year’s FTA report included one called “Making the Case”) Of course, this doesn’t even mention the Before and After Study required by all projects seeking an FFGA.