List of reporting marks: A
Note: Marks ending in U are for container owners; marks ending in X are not common carriers; marks ending in Z are for trailers without flanged wheels. All other marks are of common-carrier railroads.
Common carriers (operating railroads)
Others (assigned to companies or individuals who own railcars, but are not operating railroads)
| AAAX | Ann Arbor Railroad (1895-1976) → Ann Arbor Railroad (1988) |
| AACX | Alaska Division of Agriculture) |
| AADX | Airco Alloys and Carbide |
| AAEX | American Aniline and Extract Company |
| AAIX | ACS International Inc |
| AAKX | Amulco Asphalt Company |
| AALX | Advanced Aromatics |
| AAMX | Shippers' Car Line Division of ACF Industries; Arrendadora de Carros de Ferrocarril del Atlantico; Arrendadora de Carros de Ferrocarril |
| AARX | Association of American Railroads |
| AATX | Ampacet Corporation |
| AAX | American Agricultural Chemical Company; Agrico Chemical Company |
| ABBX | Abbott Labs |
| ABCX | American Bitumuls Company; Merchants Despatch Transportation Corporation; Falcon Coal Company; Tennessee Valley Authority |
| ABEX | Abbey Chemical Corporation; CPS Processing Corporation; CPS Chemical Company; Abbey Chemical Corporation; Advanced BioEnergy |
| ABGX | American Black Granite Company |
| ABIX | Anheuser-Busch |
| ABLX | American Refrigerator Transit Company |
| ABMX | Albers Brothers Milling Company |
| ABOX | American Rail Box Car Company; Railbox Company; TTX Company |
| ABPX | Ashland By-Product Coke Company; Animal By-Products Corporation |
| ABRX | Merchants Despatch Transportation Corporation; AB Rail Investments, Inc.; Railmark Holdings, Inc. |
| ABSX | American Beet Sugar Company; American Crystal Sugar Company; Albert Brothers Inc |
| ABTX | Aubrey Bartlett; North American Car Corporation; General Electric Railcar Services Corp. |
| ABWX | Asea Brown Boveri, Inc. |
| ABX | Adirondack Bottled Gas Corporation; Home Gas Corporation of Great Barrington |
| ACAX | Aluminum Company of America; Allied Chemical Canada; Allied Chemical Corporation; Honeywell International |
| ACBX | Scandinavian Oil Company; American Cast Iron Pipe Company |
| ACCX | Ansul Chemical Company; Consolidation Coal Company |
| ACDX | Allied Chemical Corporation; First Union Properties; Allied Chemical Corporation; Allied Signal; Honeywell International |
| ACEX | Atlantic City Electric Power Company; Atlantic Cement Company; Blue Circle Atlantic; Ace Cogeneration Company |
| ACFX | ACF Industries; General Electric Rail Services Corporation; Wells Fargo Rail |
| ACGX | Acme Gas Corporation; Suburban Propane, LP |
| ACIX | Arkansas Chemicals, Inc.; Great Lakes Chemical Corporation |
| ACJU | American Coastal Lines Joint Venture, Inc. |
| ACLU | Atlantic Container Line, Ltd. |
| ACLX | American Car Line Company |
| ACMX | Allis-Chalmers Corporation; Voith Hydro |
| ACNU | AKZO Chemie, B V |
| ACOU | Associated Octel Company, Ltd. |
| ACOX | Aurora Cooperative Elevator Company (grain shippers) |
| ACPX | Amoco Canada Petroleum Company, Ltd.; Amoco Oil Company; Union Tank Car Lines |
| ACPZ | American Concrete Products Company |
| ACRX | American Chrome and Chemicals, Inc.; Elementis Chromium, LP |
| ACSU | Atlantic Cargo Services, AB |
| ACSX | First Union Properties, Inc.; Honeywell International |
| ACSZ | American Carrier Equipment |
| ACTU | Associated Container Transport (Australia), Ltd. |
| ACTX | Allied Chemical Corporation; Honeywell International |
| ACUU | Acugreen Limited |
| ACWZ | Union Pacific Railroad |
| ACXU | Atlantic Cargo Services, AB |
| ACXX | Anderson Columbia Company, Inc. |
| ACZX | A C Railroad Service Company, Norfolk Southern Railway Company |
| ADCU | Flexi-Van Leasing, Inc. |
| ADCX | Adolph Coors Company |
| ADIX | Adirondack Railway Preservation Society (Adirondack Scenic Railroad) |
| ADKU | AGA A/S |
| ADMX | Archer Daniels Midland |
| ADRX | Addeleston Recycling Corporation |
| ADSX | Andrew Merrilees, Ltd. |
| AECX | Associated Electric Cooperative, Inc. |
| AEIX | Alan Eslisk |
| AEIZ | Farrell Lines, Inc. |
| AEPU | American Lines, Inc. |
| AEPX | American Electric Power Service Corporation |
| AEQX | ATEL Equipment Corporation |
| AESX | A. E. Staley Manufacturing; GE Railcar Services Corporation |
| AEVX | AKZO Coatings, Inc. |
| AEX | The Andersons |
| AFCU | Afram Lines, Inc. |
| AFCX | Atel Capital Equipment Fund |
| AFCZ | Afram Lines, Inc. |
| AFEX | Farmers Elevator Company of Arthur, ND |
| AFFX | AFFCAR, Inc. |
| AFIU | ABS Industrial Verification, Inc. |
| AFIZ | Agmark Foods |
| AFPX | Fibers and Plastics Company (Allied Corporation); Honeywell International |
| AFRX | AF Railway Industries, Inc. |
| AFSX | Astoria, LLC |
| AFTX | American Freedom Train |
| AGCX | Alberta Gas Chemicals, Inc.; PROCOR |
| AGEX | A. G. Pipe Lines, Inc.; Nova Chemicals, Ltd. |
| AGFX | Anchor Gas and Fuel Company, Inc. |
| AGHX | Agrium US, Inc. |
| AGIX | AGRI Financial Services, Inc.; AGRI Industries |
| AGLX | Andrews Gas Liquids Service; Andrews Petroleum |
| AGMX | Terra Nitrogen, LP |
| AGPX | AG Processing, Inc. |
| AGRX | Agrifos, LLC |
| AGYX | American Gypsum Company; Centrex Construction Products, Inc. |
| AHCX | Arcadian Corporation |
| AHMX | Altos Homos de Mexico, SA de CV |
| AHWZ | Fox Valley and Western |
| AICX | Hoeganaes Corporation |
| AIDU | Albermarle Corporation |
| AIEU | Aviation Import Export, Inc. |
| AIIZ | III Transportation |
| AIMX | American Iron & Metal Company |
| AINX | TTX Company (Acorn Division) |
| AIPX | Atlas Iron Processors, Inc. |
| AITU | Western Intermodal |
| AJCU | Australia Japan Container Line |
| AJPX | North American Chemical Company; IMC Chemicals |
| AKFX | AKF Corporation |
| AKLU | K Line |
| AKMX | Helm Financial Corporation |
| AKZX | Azko Nobel Chemicals, Inc. |
| ALAX | Lyondell Petrochemical; Equistar Chemicals, LP |
| ALBX | Albert City Elevator |
| ALCX | Aluminum Company of Canada, Ltd.; Alcan Smelters and Chemicals, Ltd. |
| ALEX | AGRI Financial Services, Inc.; AGRI Industries |
| ALGX | Amsterdam Leasing |
| ALKX | Airlake Terminal Railway Company |
| ALLX | Alliance Machine Company |
| ALLZ | Alliance Shippers |
| ALMX | Trinity Rail Management, Inc. |
| ALNX | Government of Alberta |
| ALPX | Government of Alberta |
| ALRX | A and R Leasing, LLP |
| ALSX | Albis Canada, Inc. |
| ALTU | VTG Vereinigte Tanklage U Transportmittel, GMBH |
| ALTX | Southern Illinois Railcar, Inc. |
| ALUX | Alumax of South Carolina, Inc. |
| ALWX | GE Railcar Services Corporation |
| AMAX | AMAX Coal Company |
| AMBU | Amber Line, Inc. |
| AMBX | Amherst Industries, Inc.; American Boiler Works, Inc. |
| AMCX | Amoco Chemicals Corporation; Amoco Oil Company; BP Amoco Chemical Company (Chemical Division) |
| AMCZ | Interbulk, Inc. |
| AMEX | Albamex; Allied Enterprises |
| AMFU | Amphibious Container Leasing, Ltd. |
| AMGX | AMG Resources Corporation |
| AMIU | American Marine Industries |
| AMIX | Railcar Leasing Specialists, Inc. |
| AMIZ | American Marine Industries |
| AMLX | American Railcar Company |
| AMMU | Hyundai |
| AMMX | Amoco Minerals Company; Kentucky-Tennessee Clay Company |
| AMNX | American Railcar Leasing Partners |
| AMOX | Amoco Oil Company; BP Products North America, Inc. |
| AMOZ | American Oil Company |
| AMPX | GE Railcar Services Corporation |
| AMRU | Alaska Marine Lines, Inc. |
| AMRX | Consolidated Oil and Transportation Company, Inc. |
| AMRZ | American Chassis Leasing, Inc. |
| AMSX | AllTrans Management Services Corporation |
| AMTZ | Amtrak |
| AMWX | Amway Corporation |
| AMXU | Americas Marine Express, Inc. |
| ANAU | Alliance Navigation Line, Inc. |
| ANAX | Excel Railcar Corporation; GE Rail Services Corporation |
| ANBX | Anbel Corporation |
| ANCX | Norit Americas, Inc. |
| ANDX | Andesite Rock Company |
| ANIX | Associacion National de la Industria Quimca, A.C. |
| ANKX | A and K Railroad Materials, Inc. |
| ANSX | Ansco Investment Company |
| AOCU | Associated Octel |
| AOCX | Aluminum Company of America (Alcoa) |
| AOEX | American Orient Express Railway |
| AOIX | Marathon Ashland Petroleum Company |
| AOKX | Greenbrier Management Services, LLC |
| AOUX | Alberta and Orient Glycol Company, Ltd. |
| APAX | West Penn Power Company; Cementos Apasco, SA de CV |
| APAXX | Cementos Apasco, SA de CV |
| APCU | American President Lines, Ltd. |
| APCX | Allied Products Company; Allied Lime Company |
| APEX | Apex Tank Car Line |
| APHX | Air Products Polymers, LP |
| APIX | The Commonwealth Plan, Inc. |
| APLU | American President Lines, Ltd. |
| APLX | APL Land Transport Services, Inc. |
| APLZ | American President Lines, Ltd. |
| APMU | Maersk Lines |
| APMX | Air Products Manufacturing Company |
| APMZ | Maersk Equipment Service Company |
| APOX | Alabama Power Company |
| APRX | Air Products |
| APSX | Arizona Public Service Company |
| APTX | Air Products |
| APWX | Appalachian Power Company |
| APXX | Alberta Prairie Railway Excursions |
| AQCX | Aqua-Chem, Inc. (Celaver Brooks Division) |
| ARCX | Alaska Rail Car Company; Arizona Rail Car, Inc. |
| ARDU | CATU Containers, SA |
| AREX | Aeropres Corporation |
| ARGX | Associated Railcar, Inc. |
| ARHU | CATU Containers, SA |
| ARHX | Arch Mineral Corporation |
| ARIX | Arco Industrial Gases (a division of Arco, Inc.); GE Rail Services Corporation |
| ARJX | Arch Chemicals |
| ARL | Armour Refrigerator Line (expired) |
| ARMH | Missouri Pacific Railroad; Texas-New Mexico Railway; Doniphan, Kensett and Searcy Railway; Missouri Pacific Railroad; Union Pacific Railroad |
| ARMN | Missouri Pacific Railroad; Union Pacific Railroad |
| ARMX | American Rail and Marine Corporation |
| ARMZ | Armasal Line |
| AROX | GATX Corporation |
| ARPX | Arco Petroleum Products Company; BP Products North America, Inc. |
| ARRX | Anaconda Minerals Company; Anthracite Railroads Historical Society, Inc. |
| ARSX | Aristech Chemical Corporation; Sunoco, Inc. |
| ARTU | CATU Containers, SA |
| ARWX | Alabama River Woodlands, Inc. |
| ASCX | Algoma Steel Corporation; Armco Steel Company, LP |
| ASDX | Allied Services |
| ASGX | American Steel Foundries, Inc. |
| ASHU | Anchorage Sand and Gravel Company; Ash Grove Cement Company |
| ASHC | Maritainer France, SA |
| ASHX | General American Transportation Corporation; American Soda, LLP |
| ASLX | Algoma Steamships, Ltd. |
| ASMX | Ames And Sons Machine Works |
| ASRX | Amstar Corporation; Domino Sugar Company |
| ASRZ | Agri/Share Cooperative |
| ASTX | ASARCO |
| ASYX | Avondale Shipyards, Inc. |
| ATAX | Arizona Transit Assembly; Alameda Corridor Transportation Authority |
| ATCX | Austin and Texas Central Railroad; Southern Illinois Railcar, Inc. |
| ATEX | Asplundh Tree Expert Company (Railroad Division) |
| ATGU | Burlington Northern and Santa Fe Railway; BNSF Railway |
| ATGX | ATEL Leasing Corporation |
| ATIU | Societe Auxillaire De Transport Et D'Industries |
| ATIX | Alstom Transportation, Inc. |
| ATLU | American Marine Industries |
| ATLX | Atlas Machine and Iron Works, Inc. |
| ATLZ | American Marine Industries |
| ATMX | United States Department of Energy (Albuquerque Operations Office) |
| ATOU | Atochem |
| ATTX | Trailer Train Company; TTX Corporation |
| AUBX | US Plastic Lumber, Ltd. |
| AVCX | AVCO Aerostructures Division |
| AVLU | Allied Van Lines |
| AWCX | Airco Welding Products |
| AWDX | Atlantic of New York, Inc. |
| AWIX | Albright and Wilson Americas, Inc. |
| AWVX | 20th Century Fox |
| AWXX | East Carbon Development Company |
| AWZZ | McCloud Railway Company |
| AXCU | Ace Transportation Company |
| AXXZ | Agricultural Express of America |
| AZCX | Azcon Corporation |
| AZEX | Arizona Electric Power Cooperative, Inc. |
| AZMX | Arizona Railway Museum |
| AZXX | Arizona Chemical Company |