In 1947, the newly formed Metropolitan Transit Authority (M.T.A.) decided to build to Lynn as a rapid transit line, and construction began in October 1948. The first part of the Revere Extension opened to Orient Heights on January 5, 1952, with intermediate stations at Airport and Day Square, and to Suffolk Downs on April 21, 1952. The second phase (cut short due to limited funds, and possibly due to the Eastern Massachusetts wielding its influence to protect its business in Lynn) opened to Wonderland on January 19, 1954 with intermediate stations at Beachmont and Revere Beach. All stations from Orient Heights to Wonderland were located at the sites of former BRB&L stations. The line was renamed as the Blue Line in 1965.