 The Central Rail Extension Mobility Study Final Report proposed that the D Line stations from 20th & Welton to 30th & Downing and future extension stations be operated on an independent route.This route would operate from the downtown loop to a new terminus created by sharing the A Line's 38th & Blake station.Former D Line riders would have to transfer to the new L Line as the D Line's new northern terminus would be the downtown loop (nominally 18th & California station).