| 14801 | ATSI | AAA TRUCKING SERVICE INC | | | SCAC3 |
| 14802 | ATSJ | A T T S INC | | | SCAC3 |
| 14803 | ATSK | ATS INC | | | SCAC3 |
| 14804 | ATSK | ATS INC | | | SCAC4 |
| 14805 | ATSL | ATLAS FREIGHT LINES | | | SCAC3 |
| 14806 | ATSL | ARMSTRONG MOVING & STORAGE | | | SCAC4 |
| 14807 | ATSM | ATLAS METAL & IRON CORP | | | SCAC3 |
| 14808 | ATSN | ATSL, INC | | | SCAC3 |
| 14809 | ATSO | ACME TRANSFER AND STORAGE | | | SCAC3 |
| 14810 | ATSO | APOLLO TRANSPORTATION SOLUTIONS LLC | | | SCAC4 |
| 14811 | ATSP | AMERICAN TRUCK STOP | | | SCAC3 |
| 14812 | ATSP | ACTIVA TRANSPORTES Y SERVICIOS ESPE | | | SCAC4 |
| 14813 | ATSR | ATS TRANSPORT INC | | | SCAC3 |
| 14814 | ATSR | A T SERVICES PETERBOROUGH ON | | | SCAC4 |
| 14815 | ATSS | AMERISTAR TRANSPORTATION SERVICES I | | | SCAC3 |
| 14816 | ATST | APOLLO AIR FREIGHT CORP | | | PWRC |
| 14817 | ATST | ATLAS TRUCKING | | | SCAC3 |
| 14818 | ATST | ATS TRANSPORT | | | SCAC4 |
| 14819 | ATSU | ANSTO | | AUS | BIC |
| 14820 | ATSU | The Atchison, Topeka and Santa Fe Ry. Co. | added 4/1975; eliminated 10/1976 | | NAKINA |
| 14821 | ATSU | The Atchison, Topeka and Santa Fe Ry. Co. | added 4/75 | | NRHS |
| 14822 | ATSU | BURLINGTON NORTHERN AND SANTA FE [ATCHISON, TOPEKA & SANTA FE] | | | PWRC |
| 14823 | ATSV | AUTOMOBILE TRANSPORT SUPPLY LTD | | | SCAC4 |
| 14824 | ATSW | AMERICAN TRANSPORT SYSTEMS | | | SCAC3 |
| 14825 | ATSW | AMERICAN TRANSPORT SYSTEMS | | | SCAC4 |
| 14826 | ATSX | Atlantic Sugar Refineries Ltd. | added 4/1956; 10/1957-4/1961; eliminated 1/1963 | | NAKINA |
| 14827 | ATSX | Atlantic Sugar Refineries Co. Ltd. | added 1/1963; 7/1965; 4/1970; eliminated 10/1971 | | NAKINA |
| 14828 | ATSX | Atlantic Sugar Refineries Co. Ltd. | 10/57-4/70; eliminated 10/71 | | NRHS |
| 14829 | ATSX | ATLANTIC SUGAR REFINERIES CO. | | | PWRC |
| 14830 | ATSX | ATLANTIC SUGAR REFINERIES CO LTD | | | SCAC3 |
| 14831 | ATSY | ARIES TRANSPORTATION SYSTEM INC | | | SCAC3 |
| 14832 | ATSY | ALPHA TRANSPORTATION SYSTEMS INC | | | SCAC4 |
| 14833 | ATT | Aer Turas Teoranta | Callsign: Aerturas, Ceased operations on 02 July 2003. | IRL | AVCODES |
| 14834 | ATT | Aer Turas Teoranta | IATA: QT, Callsign: Quebec Tango, | IRL | AVCODES |
| 14835 | ATT | Air Tashkent | Callsign: Hann, | UZ | AVCODES |
| 14836 | ATT | Aer Turas | | | ICAO1 |
| 14837 | ATT | ACE TRANSPORTATION COMPANY INC. | | | PWRC |
| 14838 | ATTA | ATLANTIC TRANSFER | | | SCAC3 |
| 14839 | ATTA | ANTLER TRANSPORT LLC | | | SCAC4 |
| 14840 | ATTB | A & T TRANSPORT | | | SCAC3 |
| 14841 | ATTC | ATLANTIC NATIONWIDE TRUCKING | | | SCAC4 |
| 14842 | ATTD | ALA-TEC TRANSPORTATION INC | | | SCAC3 |
| 14843 | ATTD | AUTO TRANSPORTES DIVISION PANZER S | | | SCAC4 |
| 14844 | ATTE | A TRUCK & TRAILER SALES & SERVICE C | | | SCAC3 |
| 14845 | ATTF | ATKINSON TRANSFER INC | | | SCAC3 |
| 14846 | ATTG | ATLAS TRUCKING INC | | | SCAC3 |
| 14847 | ATTH | AMERICAN TRANSBRIDGE TECHNOLOGIES I | | | SCAC4 |
| 14848 | ATTI | AYCOCK, TOM TRANSPORT INC | | | SCAC3 |
| 14849 | ATTI | ALL TEXAS TRUCKING INC | | | SCAC4 |
| 14850 | ATTJ | ATTCO INC | | | SCAC3 |
| 14851 | ATTJ | AUTOTRANSPORTES JAUMAVE SA DE CV | | | SCAC4 |
| 14852 | ATTL | A & T TRANSPORTATION INC | | | SCAC3 |
| 14853 | ATTM | ATLAS TRANSPORTATION CO INC | | | SCAC3 |
| 14854 | ATTN | A T TRANSPORT INC | | | SCAC3 |
| 14855 | ATTN | ALL THAT TRUCKING INC | | | SCAC4 |
| 14856 | ATTO | ALL TOGETHER TOURS | | | SCAC4 |
| 14857 | ATTP | ATC TRANSPORT LLC | | | SCAC4 |
| 14858 | ATTQ | ATLANTA TRANSFER CO | | | SCAC3 |
| 14859 | ATTQ | ALL TOGETHER TRANSPORTATION SYSTEMS | | | SCAC4 |
| 14860 | ATTR | ATLAS TRANSPORT | | | SCAC3 |
| 14861 | ATTS | ATWOOD, W E TRUCK SERVICE | | | SCAC3 |
| 14862 | ATTT | ARNETT TRANSPORTS | | | SCAC3 |
| 14863 | ATTV | ANDERSEN TOUR & TRAVEL SERVICE | | | SCAC3 |
| 14864 | ATTV | ALL TRUCK TRANSPORTATION CO INC (DE | | | SCAC4 |
| 14865 | ATTX | Trailer Train Co. | 7/1965-1/1980; eliminated 1/1992 | | NAKINA |
| 14866 | ATTX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 14867 | ATTX | American Turpentine & Tar Co. (, Ltd.) | 8/1920-1/1952; eliminated 4/1953; added 4/1953; 7/1954; eliminated 4/1956; added 4/1956; 10/1957; eliminated 10/1960 | | NAKINA |
| 14868 | ATTX | Trailer Train Co. (FC flats equipped with 2 continuous tie-down anchor bars applied to centre sills and 2 continuous side tie-down rails. Cars are not equipped with jacks, chains, hitch and safety chains) | 4/1963-10/1968 | | NAKINA |
| 14869 | ATTX | Trailer Train Co./TTX Co. (flat cars equipped with 2 continuous tie-down loops on centre sills, continuous tie-down rails on each side and bridge plates. Not equipped with hitches, chains, jacks, etc.) | 4/1970-1/1994 | | NAKINA |
| 14870 | ATTX | TTX Co. (60 ft. COFC flatcars, equipped with spark shields and container latches, capable of carrying 3-20 ft. containers, or 1-40 ft. and 1-20 ft. container, fully loaded to a maximum gross weight per car (containers and lading) of 159,000 lbs.) | 7/2000 | | NAKINA |
| 14871 | ATTX | American Turpentine & Tar Co., Ltd. | 4/38-10/57; eliminated 10/60 | | NRHS |
| 14872 | ATTX | Trailer Train Co. | Jul-65 | | NRHS |
| 14873 | ATTX | Trailer Train Co. (FC flats equipped with 2 continuous tie-down anchor bars applied to centre sills and 2 continuous side tie-down rails. Cars are not equipped with jacks, chains, hitch and safety chains) | 10/66-10/68 | | NRHS |
| 14874 | ATTX | Trailer Train Co. | Apr-70 | | NRHS |
| 14875 | ATTX | Trailer Train Co. (flat cars equipped with 2 continuous tie-down loops on centre sills, continuous tie-down rails on each side and bridge plates. Not equipped with hitches, chains, jacks, etc.) | 1/75-1/80 | | NRHS |
| 14876 | ATTX | Trailer Train Co. | eliminated 1/92 | | NRHS |
| 14877 | ATTX | TTX Co. | added 1/92 | | NRHS |
| 14878 | ATTX | TTX Co. (flat cars equipped with 2 continuous tie-down loops on centre sills, continuous tie-down rails on each side. Not equipped with hitches, chains, jacks, etc.) | Jan-94 | | NRHS |
| 14879 | ATTX | TTX Co. (60 ft. COFC flatcars, equipped with spark shields and container latches, capable of carrying 3-20 ft. containers, or 1-40 ft. and 1-20 ft. container, fully loaded to a maximum gross weight per car (containers and lading) of 159,000 lbs.) | Jul-00 | | NRHS |
| 14880 | ATTX | *AMERICAN TURPENTINE & TAR CO. LTD. | | | PWRC |
| 14881 | ATTX | +TTX COMPANY - TRAILER TRAIN CO. | | | PWRC |
| 14882 | ATTX | American Turpentine & Tar (TTX Corporation) | | | RSRV |
| 14883 | ATTX | TTX COMPANY | | | SCAC4 |
| 14884 | ATTY | ARNETT TRUCKING COMPANY | | | SCAC3 |
| 14885 | ATTY | ACTION TRANSPORT | | | SCAC4 |
| 14886 | ATU | Atlant Aerobatics Ltd. | Callsign: Atlant-Hungary, | H | AVCODES |
| 14887 | ATU | Air Toulon | Callsign: Toulon, | F | AVCODES |
| 14888 | ATU | Aerotours GmbH | Callsign: Berlin Sky, | D | AVCODES |
| 14889 | ATU | Atlant Aerobatics Ltd. | | | ICAO1 |
| 14890 | ATUA | ANDYS TRUCKING COMPANY | | | SCAC3 |
| 14891 | ATUB | ADVENTURE TOUR & TRAVEL | | | SCAC3 |
| 14892 | ATUB | ADVANCED TRUCKING & LOGISTICS LLC | | | SCAC4 |
| 14893 | ATUC | A TOUCH OF CLASS LIMOUSINE | | | SCAC3 |
| 14894 | ATUC | A PLUS TRANSPORTATION INC | | | SCAC4 |
| 14895 | ATUD | AMERICAN TRUCKING U S A INC | | | SCAC3 |
| 14896 | ATUD | ALVARADO TRUCKING | | | SCAC4 |
| 14897 | ATUE | A TOUCH OF ELEGANCE | | | SCAC3 |
| 14898 | ATUG | ALEXANDRIA TRUCKING & UNDERGROUND C | | | SCAC3 |
| 14899 | ATUH | ANDERSON TRUCKING COMPANY | | | SCAC3 |
| 14900 | ATUH | AMERICAN TRANSPORTATION SERVICES IN | | | SCAC4 |
