Governor Deval Patrick, MassDOT Secretary and CEO Richard A. Davey, Congressman Michael Capuano, Somerville Mayor Joseph Curtatone, and state and local elected officials kikced off phase 1 of the Green Line Extension on Tuesday, Dec. 11, at 1:30 p.m.

The location is 180 Somerville Ave., Somerville. As you enter the Target parking lot, go to the left and head toward the back of the store parking lot.

Phase I of the project consists of the reconstruction of the Harvard Street railroad bridge in Medford, and the Medford Street railroad bridge in Somerville.

Both bridges will be rebuilt to accommodate both the existing Commuter Rail tracks and the Green Line tracks.

Phase I also consists of the demolition of a building at 21 Water St., East Cambridge. The building, owned by the MBTA, will be razed to clear the path for the eventual extension of the tracks from Lechmere Station. Work under this $12.9 million effort will be done by Barletta Heavy Division.