Alexander Thompson / somerville@wickedlocal.com Massachusetts Bay Transportation Authority officials announced that the Green Line Extension is 62% complete and on track to be open for business on schedule by December 2021 at virtual public meeting on Dec. 9. “We’re far into the construction, and we’ve actually already begun the testing and commissioning piece,” GLX program manager John Dalton said. “Things are certainly moving along.” Staying safe during COVID As with everything else, the GLX project has had to adapt to the challenges presented by the pandemic. As of Dec. 8, 21 GLX workers have tested positive for the novel coronavirus since the beginning of the pandemic, according to Dalton. That is on a project that regularly involves 650 workers a day.