specials to Chambers Street were sporadically added and removed, eventually becoming an addition to the line. At one time, including during 1931, additional midday service operated local between 57th Street and Whitehall Street–South Ferry. The 2 also used the Nassau Street Loop during rush hours, entering Manhattan via the Manhattan Bridge or Montague Street Tunnel and leaving via the other. On October 17, 1949, the platform edges on the BMT Astoria Line had been shaved back to accommodate the larger BMT trains, and the BMT's Astoria Shuttle was replaced with service from the 2 Fourth Avenue Line operating from Astoria–Ditmars Boulevard in Astoria, Queens to Bay Ridge–95th Street in Brooklyn at all times. On June 29, 1950, special rush hour trains began running between Bay Ridge–95th Street and Chambers Street via the south side of the Manhattan Bridge and/or the Montague Street Tunnel. The special rush hour trains were discontinued two years later. On June 28, 1952, special service from 95th Street to the Nassau Street Line was discontinued on Saturdays. 1960s–1970s changes In the winter of 1960–61, letter designations started to appear on the route with the introduction of the R27s, which featured it on roll signs. The route was labeled the RR "Fourth Avenue Local via Tunnel". This was in accordance with the Independent Subway System's lettering system, which gave double letters to local trains and single letters to express trains. On January 1, 1961, the RR's northern terminus was relocated to its current location at Forest Hills–71st Avenue, via the BMT 60th Street Tunnel Connection, also known as the "11th Street Cut", and the IND Queens Boulevard Line. Night and weekend RR trains still terminated at 57th Street in Manhattan. Evening rush hour Fourth Avenue–Nassau trains went back to the routing that was used prior to 1959, in which trains ran from Broad Street to 95th Street via the Manhattan Bridge, and the Fourth Avenue express tracks. On November 27, 1967, the day after the Chrystie Street Connection opened, the RR was moved back to Astoria–Ditmars Boulevard on the BMT Astoria Line. Replacing it on the Queens Boulevard Line was the new EE service, running weekdays only between Forest Hills–71st Avenue and Whitehall Street (with additional trains terminating at Canal Street). The Nassau Street specials, which could no longer run as a loop via the Manhattan Bridge, were through-routed from Bay Ridge–95th Street to 168th Street in