Reporting mark

A reporting mark is a code used to identify owners or lessees of rolling stock and other equipment used on the rail transport networks of North America. The code typically reflects the name or identifying number of the owner, lessee, or operator of the equipment.

In North America the mark, which consists of an alphabetic code of two to four letters, is stenciled on each piece of equipment, along with a one- to six-digit number. This information is used to uniquely identify every such rail car or locomotive, thus allowing it to be tracked by the railway it is traveling over, which shares the information with other railways and customers.

The Association of American Railroads (AAR) assigns marks to all carriers, under authority granted by the U.S. Surface Transportation Board, Transport Canada, the British Columbia Minister of Labour, Industry, and Railways, and the governments of Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, and Panama. Railinc, a subsidiary of the AAR, maintains the active reporting marks for the North American rail industry.

Under current practice, the first letter must match the initial letter of the railroad name. As it also acts as a Standard Carrier Alpha Code, the reporting mark cannot conflict with codes in use by other nonrail carriers.