The "D" Branch, also called the Highland Branch or Riverside Branch, is a branch of the Massachusetts Bay Transportation Authority Green Line in the Boston, Massachusetts area, along which light rail vehicles run. The majority of the line is a grade-separated right-of-way formerly used by the Highland Branch of the Boston and Albany Railroad. Just west of Kenmore, the two-track line goes underground via the Fenway Incline, merging with the "B" and "C" Branches at Kenmore. From there, "D" trains continue through the Boylston Street Subway and Tremont Street Subway (merging with the "E" Branch along the way), with regular service turning around at Government Center as of 2016.