to four tracks. This section was completed in 1915. The section of the line running through the 53rd Street station opened on June 22, 1915, as part of an extension of the subway to Coney Island, which included the Fourth Avenue Line north of 59th Street as well as the entire Sea Beach Line. The line's opening was marked with a competition between two trains heading from Chambers Street station in Manhattan to the Coney Island station, one heading via the West End Line and the other via the Sea Beach Line; the latter got to Coney Island first. However, the 45th and 53rd Street stations remained closed, despite being technically complete, since the stations were being used by a contractor to haul dirt out. The stations opened on September 22, 1915. Station renovations 1920s On June 27, 1922, the New York State Transit Commission directed its engineers to prepare plans to lengthen the platforms at 23 stations on the lines of the Brooklyn–Manhattan Transit Corporation (BMT), the successor to the BRT, to accommodate eight-car trains. As part of the project, 53rd Street's platforms would have been lengthened from to . Though the Transit Commission ordered the BMT to lengthen these platforms in September 1923, progress on the extensions did not occur until February 16, 1925, when the New York City Board of Transportation (NYCBOT) directed its engineers to prepare plans to lengthen the platforms at this and eleven other stations along the Fourth Avenue Line. It estimated the project's cost to be $633,000 () (). The NYCBOT received bids for the project on February 25, 1926. The contract was awarded to the Corson Construction Company for $345,021 () (). The extensions opened on August 1, 1927. 1960s The city government took over the BMT's operations on June 1, 1940. In the 1960s, the New York City Transit Authority (NYCTA) started a project to lengthen station platforms on its lines in Southern Brooklyn to to accommodate 10-car trains. On July 14, 1967, the NYCTA awarded a contract to conduct test borings at eleven stations on the Fourth Avenue Line, including 53rd Street, to the W. M. Walsh Corporation for $6,585 () in preparation of the construction of platform extensions (). The NYCTA issued an invitation for bids on the project to extend the platforms at stations along the Fourth Avenue Line between 45th Street station and Bay Ridge—95th Street, including