Section 51 - Construction of public buildings1.(a) In addition to any other requirements respecting the construction of a public building and facilities thereof, the new construction, reconstruction, rehabilitation, alteration or improvement of all such buildings and facilities shall conform to the requirements of the state building construction code relating to facilities for the physically handicapped, except work already completed, work in progress, or work for which schematic designs have been approved by the effective date of this act. This section shall not be effective if its provisions will impair the structural stability of the public building or its facilities.(b)[The provisions of par (b) of sub. 1 and sub. 2 are subject to expiration on July 26, 2020 if the Metropolitan Transportation Authority does not comply with the provisions of sub. 3 of sec. 15-b of the transportation law.] This section shall not apply to the reconstruction, rehabilitation, alteration or improvement of rapid transit terminals or stations in New York city, which shall be governed by subdivision two of this section.2.[The provisions of par (b) of sub. 1 and sub. 2 are subject to expiration on July 26, 2020 if the Metropolitan Transportation Authority does not comply with the provisions of sub. 3 of sec. 15-b of the transportation law.] With respect to the reconstruction, rehabilitation, alteration or improvement of any rapid transit terminal or station of the New York city transit authority or of the Staten Island rapid transit operating authority, the obligations of such authorities for complying with the requirements of the state building construction code relating to facilities for individuals with disabilities shall be limited to its compliance with the requirements of subdivision three of section fifteen-b of the transportation law.N.Y. Pub. Bldgs. Law § 51