What if they built a $6 billion Metrorail extension and nobody came? That’s not just a rhetorical question. Last week, the Federal Transit Administration announced advanced payments for a number of its New Starts projects. On the list was Dulles Rail, which will be receiving $19.7 million (out of the total federal share of $900 million) for Phase 1 — an 11.7-mile Metrorail extension now under construction, which will run from West Falls Church to Wiehle Avenue in Reston.