Details on Green Line retaining walls and noise barriers Post published:May 30, 2012 Post category:Green Line MassDOT has posted its presentation on retaining walls and noise barriers, from the May 22 public hearing. You Might Also Like Somerville Journal: Green Line maintenance facility January 15, 2008 Coverage of Green Line petition August 4, 2011 State hears complaints about Green Line maintenance facility but doesn’t budge March 18, 2009