| 14101 | ATC | Angel Trains Cargo | | B | TRAFFIC |
| 14102 | ATCA | Astra Trans Carpatic | | RO | TRAFFIC |
| 14103 | ATCB | ATCO DISTRIBUTING CO INC | | | SCAC4 |
| 14104 | ATCC | ATLANTIC COAST ENVIRONMENTAL INC | | | SCAC3 |
| 14105 | ATCE | ATLANTIC CARRIERS INC | | | SCAC3 |
| 14106 | ATCE | ATLANTIC CARRIERS INC | | | SCAC4 |
| 14107 | ATCF | ARCTIC FORWARDING CO INC | | | SCAC3 |
| 14108 | ATCG | ALS TRUCKING CO INC | | | SCAC3 |
| 14109 | ATCG | AMS TRUCKING LLC | | | SCAC4 |
| 14110 | ATCH | ALVORD TRANSPORT COMPANY LLC | | | SCAC4 |
| 14111 | ATCH | ANGEL TRAINS SWITZERLAND | | CH | VKM |
| 14112 | ATCI | ATCO FUELS INC | | | SCAC3 |
| 14113 | ATCI | ATCO FUELS INC | | | SCAC4 |
| 14114 | ATCJ | ALT, CHRIS J INC | | | SCAC4 |
| 14115 | ATCK | A T C INC | | | SCAC3 |
| 14116 | ATCK | ATC & LOGISTICS INC | | | SCAC4 |
| 14117 | ATCL | ATC LLC | | | SCAC4 |
| 14118 | ATCM | Azienda Trasporti Collettivi e Mobilita | City: Modena | I | TRAFFIC |
| 14119 | ATCN | ANTILLES COMPANIA ARMADORA S A | | | SCAC3 |
| 14120 | ATCN | ACTIVE CANADA INC | | | SCAC4 |
| 14121 | ATCO | Arnold Transit | 1/1975-1/1980 | | NAKINA |
| 14122 | ATCO | Arnold Transit | 1/75-1/80 | | NRHS |
| 14123 | ATCO | ARNOLD TRANSIT | | | PWRC |
| 14124 | ATCO | Arnold Transit | | | RSRV |
| 14125 | ATCO | ARNOLD TRANSIT COMPANY | | | SCAC3 |
| 14126 | ATCP | ATLANTIC CITY-PHILA. EXPRESS, INC | | | SCAC3 |
| 14127 | ATCP | ATLANTIC CITY-PHILA EXPRESS INC | | | SCAC4 |
| 14128 | ATCQ | AAA TRUCKING COMPANY | | | SCAC3 |
| 14129 | ATCR | ATCS TESTING & FIELD EVALUATION | | | PWRC |
| 14130 | ATCR | Astra Trans Carpatic | Real: ATC | RO | TRAFFIC |
| 14131 | ATCS | ATCS TESTING & FIELD EVALUATION | | | PWRC |
| 14132 | ATCT | ATCS TESTING & FIELD EVALUATION | | | PWRC |
| 14133 | ATCT | ATNT TRANSPORT INC | | | SCAC4 |
| 14134 | ATCU | ALLSEAS ENGINEERING BV c/o BLUE MARINE OFFSHORE YARD SERVICE B.V. | | NL | BIC |
| 14135 | ATCU | AFRICAN TRADING CORPORATION | | | SCAC3 |
| 14136 | ATCU | ALLSEAS ENGINEERING BV | | | SCAC4 |
| 14137 | ATCV | APPLE TRANSPORTATION SERVICES | | | SCAC3 |
| 14138 | ATCV | AUTO TRANSPORTES CHRYMEX S A DE C V | | | SCAC4 |
| 14139 | ATCW | ATCO INDUSTRIES INC | | | SCAC4 |
| 14140 | ATCX | SC Rail Leasing America, Inc. d/b/a Southern Illinois Railcar Co. | added 1/2008 | | NAKINA |
| 14141 | ATCX | Southern Illinois Railcar Co. | added 10/1994; 7/2000; eliminated 7/2003; 7/2005 (not listed); eliminated 1/2008 | | NAKINA |
| 14142 | ATCX | Aiple Towing Co. | added 10/1970; eliminated 4/1973 | | NAKINA |
| 14143 | ATCX | American Tar Co. | 7/1932-1/1941 | | NAKINA |
| 14144 | ATCX | Ace Tank Car Co. | 1/1945 (not listed); 1/1946-10/1957; eliminated 7/1960 | | NAKINA |
| 14145 | ATCX | American Tar Co. | Apr-38 | | NRHS |
| 14146 | ATCX | Ace Tank Car Co. | 1/52-10/57; eliminated 7/60 | | NRHS |
| 14147 | ATCX | Aiple Towing Co. | added 10/70; eliminated 4/73 | | NRHS |
| 14148 | ATCX | Southern Illinois Railcar Co. | added 10/94; 7/2000 | | NRHS |
| 14149 | ATCX | *AMERICAN TAR CO. | | | PWRC |
| 14150 | ATCX | *ACE TANK CAR CO. | | | PWRC |
| 14151 | ATCX | *AIPLE TOWING CO. | | | PWRC |
| 14152 | ATCX | *AUSTIN & TEXAS CENTRAL RAILROAD | | | PWRC |
| 14153 | ATCX | +SC RAIL LEASING AMERICA, INC D/B/A SOUTHERN ILLINOIS RAILCAR INC. | | | PWRC |
| 14154 | ATCX | Austin and Texas Central Railroad (Southern Illinois Railcar) | | | RSRV |
| 14155 | ATCX | Austin & Texas Central | | USA | TRAFFIC |
| 14156 | ATCY | ATC TRUCKING INC | | | SCAC3 |
| 14157 | ATCZ | ATOCHEM | | | PWRC |
| 14158 | ATCZ | ASSOCIATIONS TRAILER CAR COMPANY | | | SCAC3 |
| 14159 | ATD | Aerotours Dominicana, C. Por. A. | Callsign: Aerotours, | DOM | AVCODES |
| 14160 | ATD | Aerotours Dominicana | | | ICAO1 |
| 14161 | ATDA | ALTERNATE TRANSPORT INC | | | SCAC3 |
| 14162 | ATDA | AUTO TRANSPORTE DE CARGA | | | SCAC4 |
| 14163 | ATDB | ALLSTON TRUCK DELIVERY INC | | | SCAC3 |
| 14164 | ATDC | A TEAM TRANSPORT LLC | | | SCAC4 |
| 14165 | ATDD | ALTAIR | | | SCAC3 |
| 14166 | ATDE | Alpha Trains Europa GmbH | | DE | VKM |
| 14167 | ATDF | AUTOMOTIVE TESTING & DEVELOPMENT SE | | | SCAC4 |
| 14168 | ATDG | ATLAS DISTRIBUTING INC | | | SCAC3 |
| 14169 | ATDG | AUTO TRANSPORTE DE CARGA | | | SCAC4 |
| 14170 | ATDH | ARTS TRADING CO | | | SCAC3 |
| 14171 | ATDH | ARTS TRADING CO | | | SCAC4 |
| 14172 | ATDJ | ATANASOVSKI, DRAGO | | | SCAC3 |
| 14173 | ATDJ | ATLAS INDUSTRIAL COATINGS INC | | | SCAC4 |
| 14174 | ATDK | AMERICAN TRUCK DISPATCH INC | | | SCAC4 |
| 14175 | ATDL | A-TRAN DELIVERY SERVICE INC | | | SCAC3 |
| 14176 | ATDM | ACORN TRANSIT INC | | | SCAC3 |
| 14177 | ATDM | AMERICAN TIRE DISTRIBUTORS INC | | | SCAC4 |
| 14178 | ATDN | AMERICAN TRADING TRANSPORTATION COM | | | SCAC3 |
| 14179 | ATDN | AUTOTRANSPORTES DEL CONCHOS SA DE C | | | SCAC4 |
| 14180 | ATDO | ACCREDITED MOVERS INC | | | SCAC3 |
| 14181 | ATDP | AMERICAN TRUCK DISPATCH INC | | | SCAC3 |
| 14182 | ATDQ | ATLANTA DELIVERY SERVICE | | | SCAC3 |
| 14183 | ATDR | ATLAS TRADER K/S | | | SCAC3 |
| 14184 | ATDR | AUTOTRANSPORTES DE LOS REYES | | | SCAC4 |
| 14185 | ATDV | A TIMELY DELIVERY | | | SCAC4 |
| 14186 | ATDW | AMERICAN TRANSPORTATION NATIONWIDE | | | SCAC3 |
| 14187 | ATDW | ATLAS PYROVISION PRODUCTIONS INC | | | SCAC4 |
| 14188 | ATDX | American Tar & Chemical Co. | 7/1935-4/1938 | | NAKINA |
| 14189 | ATDX | American Tar & Chemical Co. | Apr-38 | | NRHS |
| 14190 | ATDX | AMERICAN TAR & CHEMICAL CO. | | | PWRC |
| 14191 | ATDX | ARCELOR MITTAL MINES INC | | | SCAC4 |
| 14192 | ATDY | ACTIVE DELIVERY SERVICE | | | SCAC3 |
| 14193 | ATE | Atlantis Transportation Services, Ltd. | Callsign: Atlantis Canada, | CDN | AVCODES |
| 14194 | ATE | Servicio Mericano de Vuelose de Fletamento, S.A. de C.V. | Callsign: Amtravel, | MEX | AVCODES |
| 14195 | ATE | Al-Atheer Aviation | | SA | AVCODES |
| 14196 | ATE | Atlantis Transportation Services, Ltd. | | | ICAO1 |
| 14197 | ATEB | ATE LOGISTIC CO LTD | | | SCAC4 |
| 14198 | ATEC | ASCOTECH SA DE CV | | | SCAC4 |
| 14199 | ATED | ASSOCIATED SAFETY INC | | | SCAC4 |
| 14200 | ATEG | ATEN, GEORGE M | | | SCAC3 |
