((a)) ** .—** With the objective of promoting, encouraging, and developing ports and transportation facilities in connection with water commerce over which the Secretary of Transportation has jurisdiction, the Secretary, in cooperation with the Secretary of the Army, shall—

((1)) investigate territorial regions and zones tributary to ports, taking into consideration the economies of transportation by rail, water, and highway and the natural direction of the flow of commerce;

((2)) investigate the causes of congestion of commerce at ports and applicable remedies;

((3)) investigate the subject of water terminals, including the necessary docks, warehouses, and equipment, to devise and suggest the types most appropriate for different locations and for the most expeditious and economical transfer or interchange of passengers or property between water carriers and rail carriers;

((4)) consult with communities on the appropriate location and plan of construction of wharves, piers, and water terminals;

((5)) investigate the practicability and advantages of harbor, river, and port improvements in connection with foreign and coastwise trade; and

((6)) investigate any other matter that may tend to promote and encourage the use by vessels of ports adequate to care for the freight that naturally would pass through those ports.

((b)) ** .—** After an investigation under subsection (a), if the Secretary of Transportation believes that the rates or practices of a rail carrier subject to the jurisdiction of the Surface Transportation Board are detrimental to the objective specified in subsection (a), or that new rates or practices, new or additional port terminal facilities, or affirmative action by a rail carrier is necessary to promote that objective, the Secretary may submit findings to the Board for action the Board considers appropriate under existing law.