Abstract: A system for preventing damage to cargo shipped in air-ride suspension semi-trailers loaded on railroad flat cars which comprise at least part of a freight train is provided. The system comprises a coupling element connected to the air brake line of the freight train. The coupling element is connected to an air reservoir mounted on the flat car or on the semi-trailer and supplies compressed air to the reservoir from the brake line of the train. The coupling element includes a valve to prevent air from flowing from the train brake line to the air reservoir when the air pressure in the brake line drops below a predetermined safety level to prevent unwanted activation of the train's brakes. The air reservoir is connected to the air line of the semi-trailer and provides compressed air to the air bags which comprise the air suspension system of the semi-trailer.