Governor Deval Patrick, US Representative Mike Capuano, and other officials will celebrate the start of construction on the Green Line Extension project Tuesday in Somerville, according to an announcement from the Department of Transportation.
A ceremonial groundbreaking for the first phase on construction on the extension will be held at 1:30 p.m. at 180 Somerville Ave. Phase one calls for the reconstruction of two railroad bridges: one carrying tracks over Harvard Street in Medford and one over Medford Street in Somerville, according to the announcement. It also calls for an MBTA-owned building on Water Street in Cambridge to be razed. The preliminary work is expected to cost $12.9 million, the announcement said.
The extension project will stretch the Green Line from its current terminal station in East Cambridge through Somerville to Medford, creating six new stops. It is expected to be completed by 2020 and cost about $1 billion.
Transportation Secretary Richard Davey and Somerville Mayor Joseph Curtatone will also be on hand Tuesday.