MBTA Orange Line begins service.

Originally the Main Line and operated by the Boston Elevated Railway Company, it runs through downtown Boston, initially through the Tremont Street Subway tunnel and then through a new tunnel under Washington Street that is built in 1908, then on an elevated track along Washington Street between Charlestown and Roxbury. Ground was broken for the project on January 20, 1899. The line is extended to Jamaica Plain in 1909,* and to Everett on March 15, 1919. The northern branch is replaced by the new Orange Line in 1975,* and the southern branch in 1987.*