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SOMERVILLE — Mayor Joseph A. Curtatone stood on a bridge in Union Square that can be seen from Prospect Hill, where George Washington ordered his troops to raise the Grand Union flag on New Year’s Day in 1776.
The new Union Square station, part of the $1.43 billion Green Line extension, will be completed in 2017. From the bridge, Curtatone pointed to a gritty metal scrapyard and a used radiator shop next to a set of commuter rail tracks. “This will change,” said Curtatone, looking over the 3.8-acre site, where up to 600,000 square feet of new development is expected — buildings as high as 10 stories — with the subway stop as its hub. “It’s the transformation that we all dreamed about.”