This is a summary. To read the whole story subscribe to BostonGlobe.com
Governor Deval Patrick is expected to announce Wednesday morning that the MBTA Silver Line will be extended to East Boston and Chelsea, with a prospective opening date in late 2016.
The plan to expand the bus rapid transit line, mulled in transportation planning circles for years, is meant to connect the burgeoning Seaport District with Chelsea and East Boston, communities historically underserved by public transit.
Patrick’s announcement, which he is expected to make at a speech in Chelsea, comes as he continues to carve out details on how he plans to spend money for transportation investments earmarked by state legislators earlier this year.