| 1 | ATC | Air Tanzania Corporation | IATA: TC, Callsign: Tanzania, IATA Prefix: 197, Name changed to Air Tanzania Company Ltd. ICAO callsign changed from Tango Charlie | EAT | AVCODES |
| 2 | ATC | Air Tanzania Company Limited | IATA: TC, Callsign: Tanzania, IATA Prefix: 197, Name changed from Air Tanzania Corporation. ICAO callsign changed from Tango Charlie | EAT | AVCODES |
| 3 | ATC | Air Tanzania Corporation | IATA: TC, Callsign: Tango Charlie, IATA Prefix: 197, ICAO callsign changed to Tanzania | EAT | AVCODES |
| 4 | ATC | Air Tanzania | IATA: TC | | ICAO1 |
| 5 | ATC | *ASSOCIATIONS TRAILER CAR CO | | | PWRC |
| 6 | ATC | *AUTOTRAIN CORPORATION | | | PWRC |
| 7 | ATC | Angel Trains Cargo | | B | TRAFFIC |
| 8 | ATCA | Astra Trans Carpatic | | RO | TRAFFIC |
| 9 | ATCB | ATCO DISTRIBUTING CO INC | | | SCAC4 |
| 10 | ATCC | ATLANTIC COAST ENVIRONMENTAL INC | | | SCAC3 |
| 11 | ATCE | ATLANTIC CARRIERS INC | | | SCAC3 |
| 12 | ATCE | ATLANTIC CARRIERS INC | | | SCAC4 |
| 13 | ATCF | ARCTIC FORWARDING CO INC | | | SCAC3 |
| 14 | ATCG | ALS TRUCKING CO INC | | | SCAC3 |
| 15 | ATCG | AMS TRUCKING LLC | | | SCAC4 |
| 16 | ATCH | ALVORD TRANSPORT COMPANY LLC | | | SCAC4 |
| 17 | ATCH | ANGEL TRAINS SWITZERLAND | | CH | VKM |
| 18 | ATCI | ATCO FUELS INC | | | SCAC3 |
| 19 | ATCI | ATCO FUELS INC | | | SCAC4 |
| 20 | ATCJ | ALT, CHRIS J INC | | | SCAC4 |
| 21 | ATCK | A T C INC | | | SCAC3 |
| 22 | ATCK | ATC & LOGISTICS INC | | | SCAC4 |
| 23 | ATCL | ATC LLC | | | SCAC4 |
| 24 | ATCM | Azienda Trasporti Collettivi e Mobilita | City: Modena | I | TRAFFIC |
| 25 | ATCN | ANTILLES COMPANIA ARMADORA S A | | | SCAC3 |
| 26 | ATCN | ACTIVE CANADA INC | | | SCAC4 |
| 27 | ATCO | Arnold Transit | 1/1975-1/1980 | | NAKINA |
| 28 | ATCO | Arnold Transit | 1/75-1/80 | | NRHS |
| 29 | ATCO | ARNOLD TRANSIT | | | PWRC |
| 30 | ATCO | Arnold Transit | | | RSRV |
| 31 | ATCO | ARNOLD TRANSIT COMPANY | | | SCAC3 |
| 32 | ATCP | ATLANTIC CITY-PHILA. EXPRESS, INC | | | SCAC3 |
| 33 | ATCP | ATLANTIC CITY-PHILA EXPRESS INC | | | SCAC4 |
| 34 | ATCQ | AAA TRUCKING COMPANY | | | SCAC3 |
| 35 | ATCR | ATCS TESTING & FIELD EVALUATION | | | PWRC |
| 36 | ATCR | Astra Trans Carpatic | Real: ATC | RO | TRAFFIC |
| 37 | ATCS | ATCS TESTING & FIELD EVALUATION | | | PWRC |
| 38 | ATCT | ATCS TESTING & FIELD EVALUATION | | | PWRC |
| 39 | ATCT | ATNT TRANSPORT INC | | | SCAC4 |
| 40 | ATCU | ALLSEAS ENGINEERING BV c/o BLUE MARINE OFFSHORE YARD SERVICE B.V. | | NL | BIC |
| 41 | ATCU | AFRICAN TRADING CORPORATION | | | SCAC3 |
| 42 | ATCU | ALLSEAS ENGINEERING BV | | | SCAC4 |
| 43 | ATCV | APPLE TRANSPORTATION SERVICES | | | SCAC3 |
| 44 | ATCV | AUTO TRANSPORTES CHRYMEX S A DE C V | | | SCAC4 |
| 45 | ATCW | ATCO INDUSTRIES INC | | | SCAC4 |
| 46 | ATCX | SC Rail Leasing America, Inc. d/b/a Southern Illinois Railcar Co. | added 1/2008 | | NAKINA |
| 47 | ATCX | Southern Illinois Railcar Co. | added 10/1994; 7/2000; eliminated 7/2003; 7/2005 (not listed); eliminated 1/2008 | | NAKINA |
| 48 | ATCX | Aiple Towing Co. | added 10/1970; eliminated 4/1973 | | NAKINA |
| 49 | ATCX | American Tar Co. | 7/1932-1/1941 | | NAKINA |
| 50 | ATCX | Ace Tank Car Co. | 1/1945 (not listed); 1/1946-10/1957; eliminated 7/1960 | | NAKINA |
| 51 | ATCX | American Tar Co. | Apr-38 | | NRHS |
| 52 | ATCX | Ace Tank Car Co. | 1/52-10/57; eliminated 7/60 | | NRHS |
| 53 | ATCX | Aiple Towing Co. | added 10/70; eliminated 4/73 | | NRHS |
| 54 | ATCX | Southern Illinois Railcar Co. | added 10/94; 7/2000 | | NRHS |
| 55 | ATCX | *AMERICAN TAR CO. | | | PWRC |
| 56 | ATCX | *ACE TANK CAR CO. | | | PWRC |
| 57 | ATCX | *AIPLE TOWING CO. | | | PWRC |
| 58 | ATCX | *AUSTIN & TEXAS CENTRAL RAILROAD | | | PWRC |
| 59 | ATCX | +SC RAIL LEASING AMERICA, INC D/B/A SOUTHERN ILLINOIS RAILCAR INC. | | | PWRC |
| 60 | ATCX | Austin and Texas Central Railroad (Southern Illinois Railcar) | | | RSRV |
| 61 | ATCX | Austin & Texas Central | | USA | TRAFFIC |
| 62 | ATCY | ATC TRUCKING INC | | | SCAC3 |
| 63 | ATCZ | ATOCHEM | | | PWRC |
| 64 | ATCZ | ASSOCIATIONS TRAILER CAR COMPANY | | | SCAC3 |
