The district may accept contributions, grants, or loans from any public agency or the United States or any department, instrumentality, or agency thereof, for the purpose of financing the planning, acquisition, construction, or operation of public transit systems, and may enter into contracts and cooperate with, and accept cooperation from, any public agency or the United States, or agency thereof, in the planning, acquisition, construction, or operation of those systems in accordance with any legislation that Congress or the Legislature may have heretofore adopted or may hereafter adopt, under which aid, assistance, and cooperation may be furnished by the United States or any public agency in the planning, acquisition, construction, or operation of those systems. The district may do any and all things necessary in order to avail itself of that aid, assistance, and cooperation under any federal or state legislation now or hereafter enacted.