Mr. Tefs, you're looking for "Narrow Gauge, The Story of The Boston, Revere Beach & Lynn Railroad" by Robert C. Stanley. It was published by the Boston Street Railway Association in 1980. The book is soft cover and runs 120 pages with numerous photos. Also there is pocket in the back with 1/4" drawings of a coach, and 1 1/2" drawings of one of the Mason Bogies. In answer to your other question, the BRB&L owned only a few flat cars used in M/W work. They had NO freight traffic; the group that published the book is a clue as to just what BRB&L was about.