Reporting Marks are stenciled on owned and leased equipment. Marks are used as equipment ID's for all electronic interfaces between railroads, their customers, and RAILINC systems and files. Equipment Marks identify the names of railroads or private companies, junction points, stations, and interchange points. In addition, they are used for revenue accounting purposes like car hire and car repair billing.
Railroad Standard Carrier Alpha Codes (SCACs) are assigned based on operating authority approved by the Surface Transportation Board, Canadian Transportation Authority, or the Mexican Government and code availability with the National Motor Freight Traffic Association (NMFTA). All SCAC codes issued for railroads must have the first letter of the mark be the same as the company or road name and have two to four alpha characters (for example, Union Pacific Railroad Company's mark is UP and Burlington Northern and Santa Fe Railway Company's mark is BNSF).
Private Marks are assigned based on the type of equipment. These marks are four letter alpha characters ending in X or Z. All privately owned railcars end in X (for example, General American Marks Company, mark GATX). All Trailer/chassis equipment marks end in Z (for example, Transport International Pool Inc's mark is TIPZ). All container marks (ending in U) are coordinated by the NMFTA.