40 U.S.C. § 6903
Agreements and contracts
The Secretary of Transportation may make agreements and contracts, except an agreement or contract to sell property rights at the Union Station complex, with a person, a federal, regional, or local agency, or the Architect of the Capitol that the Secretary considers necessary or desirable to carry out the purposes of this subchapter.
( Pub. L. 107–217 , Aug. 21, 2002 , 116 Stat. 1201 .)