; heating the Government Publishing Office and Washington City Post Office, and heating and chilled water for air conditioning for the Supreme Court Building, the Union Station complex, the Thurgood Marshall Federal Judiciary Building and the Folger Shakespeare Library, expenses for which shall be advanced or reimbursed upon request of the Architect of the Capitol and amounts so received shall be deposited into the Treasury to the credit of this appropriation, $97,827,258, of which $15,286,617 shall remain available until September 30, 2023: Provided , That not more than $9,000,000 of the funds credited or to be reimbursed to this appropriation as herein provided shall be available for obligation during fiscal year 2019. Library Buildings and Grounds For all necessary expenses for the mechanical and structural maintenance, care and operation of the Library buildings and grounds, $64,125,666, of which $36,254,000 shall remain available until September 30, 2023. Capitol Police Buildings, Grounds and Security For all necessary expenses for the maintenance, care and operation of buildings, grounds and security enhancements of the United States Capitol Police, wherever located, the Alternate Computing Facility, and Architect of the Capitol security operations, $54,680,047, of which $28,777,000 shall remain available until September 30, 2023. Botanic Garden For all necessary expenses for the maintenance, care and operation of the Botanic Garden and the nurseries, buildings, grounds, and collections; and purchase and exchange, maintenance, repair, and operation of a passenger motor vehicle