does not apply to the transportation of merchandise loaded on a railroad car or to a motor vehicle with or without a trailer, and with its passengers or contents when accompanied by the operator, when the railroad car or motor vehicle is transported in a railroad car ferry operated between fixed terminals on the Great Lakes as part of a rail route, if—

((1)) the car ferry is owned by a common carrier by water and operated as part of a rail route with the approval of the Surface Transportation Board;

((2)) the stock of the common carrier by water, or its predecessor, was owned or controlled by a common carrier by rail prior to ;

((3)) the stock of the common carrier owning the car ferry is, with the approval of the Board, now owned or controlled by a common carrier by rail; and

((4)) the car ferry is built in and documented under the laws of the United States.