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 59th 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 this station, on May 3, 1968. However, work had already started on the platform extension project in February. The platforms were extended by to the north.