Ten years ago, Denver area voters approved by a 58-42 percent margin the Regional Transportation District's ambitious plan to build 122 miles of passenger rail line to link the metro area together — in just 12 years. That construction project — known as FasTracks — would greatly expand on RTD's existing light-rail network, which began service 20 years ago, in October 1994. The FasTracks plan, as envisioned in 2004, is still a work in progress.