| 1 | CTR | Aerolineas Centauro, S.A. de C.V. | Callsign: Centauro, | MEX | AVCODES |
| 2 | CTR | Transport Air Centre | Callsign: Air centre, | F | AVCODES |
| 3 | CTR | Aerlineas Centauro | | | ICAO1 |
| 4 | CTR | Clinton Terminal R.R. Co. | 7/2000-7/2005 | | NAKINA |
| 5 | CTR | Clinton Terminal R.R. Co. | Jul-00 | | NRHS |
| 6 | CTR | CLINTON TERMINAL RAILROAD COMPANY | | | PWRC |
| 7 | CTR | Clinton Terminal Railroad (Carlton Trail Railway) | | | RSRV |
| 8 | CTR | CLINTON TERMINAL RAILROAD | | | SCAC4 |
| 9 | CTR | Calgary Transit | | CDN | TRAFFIC |
| 10 | CTRA | Connecticut Rail Systems, Inc. | added 10/1993; eliminated 1/1994; 1/1994 (not listed) | | NAKINA |
| 11 | CTRA | Connecticut Rail Systems, Inc. | added 10/93; eliminated 1/94 | | NRHS |
| 12 | CTRA | RETIRED 05-02-94 (202) ATP [CONNECTICUT RAIL SYSTEMS, INC.] | | | PWRC |
| 13 | CTRB | CATTLE TRANSIT INC | | | SCAC3 |
| 14 | CTRB | CECCHI TRANSPORT | | | SCAC4 |
| 15 | CTRB | | City: Belfort | F | TRAFFIC |
| 16 | CTRC | CHATTANOOGA TERMINAL RAILWAY COMPANY | | | PWRC |
| 17 | CTRC | CHASON TRUCKING COMPANY INC | | | SCAC3 |
| 18 | CTRC | CLEARSPRINGS TRANSPORTATION | | | SCAC4 |
| 19 | CTRD | COLLINS TRANSPORT INC | | | SCAC3 |
| 20 | CTRD | CHICAGO TRANSPORT | | | SCAC4 |
| 21 | CTRE | CITY TRANSFER & STORAGE | | | SCAC3 |
| 22 | CTRE | CURTIS TIRE SERVICE LTD | | | SCAC4 |
| 23 | CTRF | COMMERCIAL TRANSFER, INC | | | SCAC3 |
| 24 | CTRF | CAMPA TARAZON, RAFAEL | | | SCAC4 |
| 25 | CTRH | CORNELIOS TRUCKING REFRIGERADOS SA | | | SCAC4 |
| 26 | CTRI | CORONA TRANSPORT | | | SCAC4 |
| 27 | CTRJ | CARR TRUCKING | | | SCAC4 |
| 28 | CTRK | CARPENTER TRUCKING, INC | | | SCAC3 |
| 29 | CTRL | CARROLLTON TRUCK LINE, INC | | | SCAC3 |
| 30 | CTRL | CARIBBEAN TRANSPORT LINE (USA) INC | | | SCAC4 |
| 31 | CTRL | Channel Tunnel Rail Link | | UK | VKM |
| 32 | CTRM | CENTRAL MISSOURI RELOAD INC | | | SCAC3 |
| 33 | CTRM | CENTRAL MISSOURI RELOAD INC | | | SCAC4 |
| 34 | CTRN | Union Pacific Rd. Co. | added 4/2001; 7/2005 | | NAKINA |
| 35 | CTRN | Central of Tennessee Ry. & Navigation Co. | added 4/1993; added 7/1993; 1/1994-7/2000; eliminated 4/2001 | | NAKINA |
| 36 | CTRN | Central of Tennessee Ry. & Navigation Co. | added 4/93; added 7/93; 1/94-7/2000; eliminated 4/2001 | | NRHS |
| 37 | CTRN | Union Pacific Rd. Co. | added 4/2001 | | NRHS |
| 38 | CTRN | UNION PACIFIC [CENTRAL OF TENNESSEE RAILWAY & NAVIGATION CO., INC.] | | | PWRC |
| 39 | CTRN | Central of Tennessee Railway | | | RSRV |
| 40 | CTRN | CONTRANS GMBH | | | SCAC3 |
| 41 | CTRN | CONTRANS GMBH | | | SCAC4 |
| 42 | CTRN | Central of Tennessee Ry. & Navigation Co. | | USA | TRAFFIC |
| 43 | CTRO | CLINTONS TRANSFER & STORAGE INC | | | SCAC3 |
| 44 | CTRQ | CONTRACT FREIGHTERS, INC. | | | SCAC3 |
| 45 | CTRQ | CONTRACT FREIGHTERS, INC | | | SCAC4 |
| 46 | CTRR | Cloquet Terminal R.R. Co., Inc. | added 10/2003; 7/2005 | | NAKINA |
| 47 | CTRR | CLOQUET TERMINAL RAILROAD | | | PWRC |
| 48 | CTRR | Cloquet Terminal Railroad | | | RSRV |
| 49 | CTRR | CONTRACT PIPE CARRIERS, INC | | | SCAC3 |
| 50 | CTRR | CLOQUET TERMINAL RAILROAD COMPANY I | | | SCAC4 |
| 51 | CTRS | COASTAL TRANSPORT SERVICES INC | | | SCAC4 |
| 52 | CTRT | CONTAINER TRANSPORT LLC | | | SCAC4 |
| 53 | CTRU | H.ESSERS TRANSPORT COMPANY NEDERLAND BV | | NL | BIC |
| 54 | CTRU | CONTAINER TRADING CO. | | | PWRC |
| 55 | CTRU | Container Trading | | | RSRV |
| 56 | CTRU | CENTRUM TRANSPORT BV | | | SCAC4 |
| 57 | CTRV | CONTRACTORS HAULING SERVICE, INC | | | SCAC3 |
| 58 | CTRW | Carlton Trail Ry. Co. | added 4/1998; 7/2000-7/2005 | | NAKINA |
| 59 | CTRW | Carlton Trail Ry. Co. | added 4/98; 7/2000 | | NRHS |
| 60 | CTRW | CARLTON TRAIL RAILWAY COMPANY | | | PWRC |
| 61 | CTRW | Carlton Trail Railway | | | RSRV |
| 62 | CTRW | CARLTON TRAIL RAILWAY COMPANY | | | SCAC4 |
| 63 | CTRX | Cargill Inc. | added 10/2004; 7/2005 | | NAKINA |
| 64 | CTRX | C&T Refinery, LLC | added 1/2000; 7/2000; eliminated 10/2004 | | NAKINA |
| 65 | CTRX | C&T Refinery, Inc. | added 7/1983; 1/1994; eliminated 1/2000 | | NAKINA |
| 66 | CTRX | Continental Turpentine & Rosin Corp. | added 7/1957; 10/1957-10/1966; eliminated 4/1967 | | NAKINA |
| 67 | CTRX | Chemical Transit Co. | added 1/1953; 7/1954; eliminated 4/1955 | | NAKINA |
| 68 | CTRX | Chemical Transit Co. | added 1/53; eliminated 4/55 | | NRHS |
| 69 | CTRX | Continental Turpentine & Rosin Corp. | 10/57-10/66; eliminated 4/67 | | NRHS |
| 70 | CTRX | C&T Refinery, Inc. | 1/94; eliminated 1/2000 | | NRHS |
| 71 | CTRX | C&T Refinery, LLC | added 1/2000; 7/2000 | | NRHS |
| 72 | CTRX | CARGILL, INC. [C & T REFINERY, INC.; CHAPERAL & TEXAS RAILROAD] | | | PWRC |
| 73 | CTRX | C and T Refinery | | | RSRV |
| 74 | CTRX | CONTINENTAL TURPENTINE & ROSIN CORP | | | SCAC3 |
| 75 | CTRX | CARGILL INC | | | SCAC4 |
| 76 | CTRY | CATUCCI, TROY LINE INC. | | | SCAC3 |
| 77 | CTRY | CATES TRUCKING | | | SCAC4 |
