My walk to work is rife with construction; large swaths of land are cordoned off, sidewalks reworked and traffic patterns changed, all because of a big green stripe being added to our Massachusetts Bay Transportation Authority maps. A project in the works since 1990, the Green Line Extension project only actually started to take shape in 2012. The MBTA started to put down the bones. And then it was halted. Revised. There’s a new plan now, but things still seem shaky. As it turns out, reworking a city’s transit system isn’t is easy as plopping a line down on a map. But…