Abstract: A system is provided for automatic identification of objects, such as rail cars and the like, utilizing two transponders, each attached to the rail car by a bracket. The bracket, which is welded along its ends to the rail car, has a lower planar surface which is placed against the side of the rail car when the bracket is welded thereto. A bottom planar surface of the transponder mates with an upper planar surface of the bracket, thus ensuring a good conduction heat flow path to the rail car and preventing over heating of the transponder when the rail car is placed in a thaw shed. The transponder is attached to the bracket by inserting a flange formed one end of the transponder under a clip projecting from the upper surface of the bracket. A threaded stud projecting upward from the bracket upper surface extends through a hole in a second flange formed at the other end of the transponder.