| 12701 | ARR | Alaska R.R. Corp. | added 4/85; 1/94-7/2000 | | NRHS |
| 12702 | ARR | ALASKA RAILROAD CORPORATION | | | PWRC |
| 12703 | ARR | Alaska Railroad | | | RSRV |
| 12704 | ARR | Alaska Railroad | | | RSRV |
| 12705 | ARR | Alaska Railroad | | USA | TRAFFIC |
| 12706 | ARR | ARRIVA vlaky s.r.o. | | CZ | VKM |
| 12707 | ARRB | ARNETT, ROBERT TRUCKING | | | SCAC3 |
| 12708 | ARRC | ALABAMA ROADRUNNER INC | | | SCAC3 |
| 12709 | ARRD | ARCTIC ROADRUNNER TOWING | | | SCAC3 |
| 12710 | ARRE | ARREDONDO, G, TRANSFER CO | | | SCAC3 |
| 12711 | ARRF | ARMADA REEFERS 3100 AA SCHIEDAM NL | | | SCAC3 |
| 12712 | ARRG | Altra R.R. Co. | added 10/1985; eliminated 10/1989 | | NAKINA |
| 12713 | ARRG | Altra R.R. Co. | eliminated 10/89 | | NRHS |
| 12714 | ARRG | ALTRA RAILROAD | | | PWRC |
| 12715 | ARRG | Altra Railroad | | | RSRV |
| 12716 | ARRG | ALTRA RAILROAD CO | | | SCAC3 |
| 12717 | ARRG | ARREGUIN, ALFREDO TRUCKING SERVICE/ | | | SCAC4 |
| 12718 | ARRH | ARR CORPORATION | | | SCAC3 |
| 12719 | ARRH | ARR CORPORATION | | | SCAC4 |
| 12720 | ARRI | ARROW TRANSFER AND STORAGE INC | | | SCAC3 |
| 12721 | ARRIVA | Arriva Tog | 2003 - | DK | jernbanen.dk |
| 12722 | ARRIVA | | City: London | GB | TRAFFIC |
| 12723 | ARRJ | ATLANTIC RO-RO CARRIERS INC | | | SCAC4 |
| 12724 | ARRK | ARROW TRANSFER COMPANY | | | SCAC3 |
| 12725 | ARRL | ARROW TRUCK LINES INC | | | SCAC3 |
| 12726 | ARRL | ARROW LINES TRANSPORT INC | | | SCAC4 |
| 12727 | ARRM | ARROW MOVING & STORAGE COMPANY | | | SCAC3 |
| 12728 | ARRN | ARROW SERVICE (A DIV OF HOEGH/UGLAND AUTO LIN | | | SCAC3 |
| 12729 | ARRNE | Arriva North East | | GB | TRAFFIC |
| 12730 | ARRNR | Arriva Nitra | | SK | TRAFFIC |
| 12731 | ARRNZ | ARRIVA Nové Zámky | | SK | TRAFFIC |
| 12732 | ARRO | ARROW MOVING & STORAGE | | | SCAC3 |
| 12733 | ARRO | AUTO TRANSPORTES DEL ARROYO | | | SCAC4 |
| 12734 | ARROW | Arrow Motor Coach Inc. | | USA | TRAFFIC |
| 12735 | ARRQ | ARROW MOVING & STORAGE INC | | | SCAC3 |
| 12736 | ARRR | ARAN TRANSPORTATION CO INC | | | SCAC3 |
| 12737 | ARRS | ARROW TRANSPORTATION SYSTEMS LTD | | | SCAC3 |
| 12738 | ARRS | ARRSA TRANSPORT | | | SCAC4 |
| 12739 | ARRS | Arriva Sverige AB | | S | TRAFFIC |
| 12740 | ARRT | ARROWHEAD TRANSPORTATION | | | SCAC3 |
| 12741 | ARRTEP | Arriva Teplice s.r.o. | City: Tepliece | CZ | TRAFFIC |
| 12742 | ARRTRN | Arriva Trnava | | SK | TRAFFIC |
| 12743 | ARRU | ARGON ISOTANK LTD | | | SCAC4 |
| 12744 | ARRV | ARROW VAN LINES INC | | | SCAC3 |
| 12745 | ARRW | ARROW MESSENGER SERVICE INC | | | SCAC3 |
| 12746 | ARRX | Anthracite Railroads Historical Society, Inc. | 7/2005 (not listed) | | NAKINA |
| 12747 | ARRX | Anaconda Minerals Co.—Division of Atlantic Richfield Co. | added 7/1982; eliminated 4/1988 | | NAKINA |
| 12748 | ARRX | Arco Coal Co.—Division of Atlantic Richfield Co. | added 7/1979; 1/1980; eliminated 7/1982 | | NAKINA |
| 12749 | ARRX | Arrow Refining Co. (Harvey Crude Oil Co.) | 8/1920 | | NAKINA |
| 12750 | ARRX | Arco Coal Co.--Division of Atlantic Richfield Co. | added 7/79; 1/80; eliminated 7/82 | | NRHS |
| 12751 | ARRX | Anaconda Minerals Co.--Division of Atlantic Richfield Co. | added 7/82; eliminated 4/88 | | NRHS |
| 12752 | ARRX | *ARROW REFINING CO. (HARVEY CRUDE OIL CO.) | | | PWRC |
| 12753 | ARRX | *ANACONDA MINERALS CO. [ARCO COAL CO. DIV. ATLANTIC RICHFIELD CO.] (ELIMINATED 4/1988) | | | PWRC |
| 12754 | ARRX | +ANTHRACITE RAILROADS HISTORICAL SOCIETY | | | PWRC |
| 12755 | ARRX | Anthracite Railroads Historical Society | | | RSRV |
| 12756 | ARRX | ANTHRACITE RAILROADS HISTORICAL SOC | | | SCAC4 |
| 12757 | ARRY | ARROYO TRUCKING INC | | | SCAC3 |
| 12758 | ARRY | ARRENDADORA Y TRANSPORTADORA BERNAL | | | SCAC4 |
| 12759 | ARRY | Arriva Yorkshire | | GB | TRAFFIC |
| 12760 | ARS | Aeronaves Hafe, S.A. de C.V. | Callsign: Hafe, | MEX | AVCODES |
| 12761 | ARS | Air Sardinia International | | I | AVCODES |
| 12762 | ARS | Jetrider International | Callsign: Jetrider, ICAO designator changed to JRI | GB | AVCODES |
| 12763 | ARS | Air Sardinia Ltd. | | GB | AVCODES |
| 12764 | ARS | Aeromet Servicios | | | ICAO1 |
| 12765 | ARS | Arkansas Southern R.R. | added 4/2008 | | NAKINA |
| 12766 | ARS | ARKANSAS SOUTHERN RAILROAD | | | PWRC |
| 12767 | ARS | Arkansas Southern Railroad | | | RSRV |
| 12768 | ARS | ARKANSAS SOUTHERN RAILROAD | | | SCAC4 |
| 12769 | ARS | ARS Altmann AG | | D | TRAFFIC |
| 12770 | ARS | ARS Altmann AG | | DE | VKM |
| 12771 | ARSB | ARSENBERGER TRUCKING CO | | | SCAC3 |
| 12772 | ARSB | ARSENBERGER TRUCKING CO | | | SCAC4 |
| 12773 | ARSC | ARTIC STORAGE COMPANY | | | SCAC3 |
| 12774 | ARSD | AERO SPEED MAIL SERVICE, INC | | | SCAC3 |
| 12775 | ARSD | AIRSPEED INTERNATIONAL CORP | | | SCAC4 |
| 12776 | ARSE | ARSENAULT TRUCKING | | | SCAC4 |
| 12777 | ARSF | AIRCRAFT SERVICE CO | | | SCAC3 |
| 12778 | ARSF | ALLIANCE RELOCATION SERIVCES LLC | | | SCAC4 |
| 12779 | ARSG | ARMSTRONG MOVING & STORAGE INC | | | SCAC3 |
| 12780 | ARSG | ARMSTRONG MOVING & STORAGE INC | | | SCAC4 |
| 12781 | ARSI | ARIES R & T TRUCKING INC | | | SCAC3 |
| 12782 | ARSI | ACE RELOCATION SYSTEMS INC OF IL | | | SCAC4 |
| 12783 | ARSJ | ARCTIC SPAS | | | SCAC4 |
| 12784 | ARSK | ARIAS SONS TRUCKING | | | SCAC4 |
| 12785 | ARSLO | Arriva Slovenija | | SLO | TRAFFIC |
| 12786 | ARSM | ALLIED RELOCATION SERVICES INC | | | SCAC3 |
| 12787 | ARSN | AIR SUNSHINE (AIR CODE YI) | | | SCAC4 |
| 12788 | ARSO | ADVANCE RELOCATION & STORAGE SYSTEM | | | SCAC3 |
| 12789 | ARSO | ADVANCE RELOCATION & STORAGE SYSTEM | | | SCAC4 |
| 12790 | ARSP | AIR-SHIP PACKERS INC | | | SCAC3 |
| 12791 | ARSR | ARTESIAN TRANSPORTATION INC | | | SCAC3 |
| 12792 | ARSS | AIRO SERVICES INC | | | SCAC3 |
| 12793 | ARSS | Arriva Southend-on-Sea | | GB | TRAFFIC |
| 12794 | ARSSA | Acciona Rail Services s.a. | | ES | VKM |
| 12795 | ARST | ARMS WAY TRANSPORT INC | | | SCAC3 |
| 12796 | ARST | ART TRANSPORTATION SERVICES LLC | | | SCAC4 |
| 12797 | ARSU | ATC LLC | | RUS | BIC |
| 12798 | ARSU | ALPINA REEDEREI AG | | | SCAC3 |
| 12799 | ARSW | ALLEGHENY SOUTHERN RWY | | | SCAC3 |
| 12800 | ARSX | Sunoco Inc. (R&M) | added 4/2002; 7/2005 | | NAKINA |
