sentences:  The transit mall opened in 1977 and until light rail trains were added in 2009, buses were the only transit vehicles using it.The mall was rebuilt and extended southwards from 2007 to 2009, and it reopened for buses on May 24, 2009.Light rail service on the mall was introduced on August 30, 2009, with the shifting of the MAX Yellow Line to the mall from its original routing in downtown, and a second MAX line, the Green Line, began serving the mall a month later on September 12.