Last summer, the two bridges that will carry Expo Line trains over Venice Boulevard were little more than a couple of empty rebar cages.  Just over half-a-year later, the concrete has cured and the only things missing from the above picture are steel rails and catenary wiring.  Now carrying over 27,000 passengers on a daily basis, the Expo Line officially surpassed its 2020 ridership projection seven years ahead of schedule.  That's a positive sign, given that extensions are currently in the works at both ends of the line.  Expo's Phase II, which extends rail service into the heart of Downtown Santa Monica, is expected to open sometime between 2015 and 2016.  Fifteen miles east in Downtown Los Angeles, Metro expects construction to begin on the Regional Connector later this year.  The Regional Connector, which received a $670 million grant from the Federal Government this past week, will link the Blue and Expo Lines to the Pasadena and East LA branches of the Gold Line.  Traveling 1.9 miles between the Financial District and Little Tokyo, the new subway tunnel is anticipated to generate an additional 17,000 daily riders.