| 10001 | TTQC | TOTAL CARE LOGISTICS INC | | | SCAC4 |
| 10002 | TTQF | TRANSPORTES FLORES | | | SCAC4 |
| 10003 | TTQH | THOMAS TRANSPORTATION | | | SCAC4 |
| 10004 | TTQL | TRANSPORT TRAILER INC | | | SCAC4 |
| 10005 | TTQR | TTR SHIPPING | | | SCAC4 |
| 10006 | TTQS | TOTAL TRANSPORTATION SYSTEMS INC | | | SCAC4 |
| 10007 | TTQT | TTQ ENTERPRISES INC | | | SCAC4 |
| 10008 | TTQW | TRANSRITE TRANSPORTATION SERVICES L | | | SCAC4 |
| 10009 | TTQX | Trailer Train Co. | added 4/1991; eliminated 1/1992 | | NAKINA |
| 10010 | TTQX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 10011 | TTQX | Trailer Train Co./TTX Co. (flat cars equipped with excessive height fully enclosed tri-level auto racks furnished by participant railroads — requires special clearance authority for movement either loaded or empty) | added 4/1991; 10/1991-1/1994 | | NAKINA |
| 10012 | TTQX | TTX Co. (flat cars equipped with excessive height fully enclosed tri-level auto racks furnished by participant railroads — requires special clearance authority for movement either loaded or empty, equipped with end of car cush.) | 7/2000 | | NAKINA |
| 10013 | TTQX | Trailer Train Co. | added 4/91; eliminated 1/92 | | NRHS |
| 10014 | TTQX | TTX Co. | added 1/92 | | NRHS |
| 10015 | TTQX | TTX Co. (flat cars equipped with excessive height fully enclosed tri-level auto racks furnished by participant railroads -- requires special clearance authority for movement either loaded or empty) | Jan-94 | | NRHS |
| 10016 | TTQX | TTX Co. (flat cars equipped with excessive height fully enclosed tri-level auto racks furnished by participant railroads -- requires special clearance authority for movement either loaded or empty, equipped with end of car cush.) | Jul-00 | | NRHS |
| 10017 | TTQX | TTX COMPANY {TRAILER TRAIN COMPANY} | | | PWRC |
| 10018 | TTQX | Trailer Train (TTX Corporation) | | | RSRV |
| 10019 | TTQX | TTX COMPANY | | | SCAC4 |
| 10020 | TTR | Tatra Air | Callsign: Tatra, | SK | AVCODES |
| 10021 | TTR | Transportaciones Y Servicios Aereos, S.A. de C.V. | Callsign: Transportaciones, | MEX | AVCODES |
| 10022 | TTR | Transportaciones Y Servicios Aereos | | | ICAO1 |
| 10023 | TTR | Tijuana & Tecate Ry. Co. | 1/1975-1/1980 | | NAKINA |
| 10024 | TTR | Talleyrand Terminal R.R. Co., Inc. | 7/2000-7/2005 | | NAKINA |
| 10025 | TTR | Tijuana & Tecate Ry. Co. | 1/75-1/80 | | NRHS |
| 10026 | TTR | Talleyrand Terminal R.R. Co., Inc. | Jul-00 | | NRHS |
| 10027 | TTR | *TIJUANA & TECATE RAILWAY | | | PWRC |
| 10028 | TTR | +TALLEYRAND TERMINAL RAILROAD COMPANY | | | PWRC |
| 10029 | TTR | Tijuana and Tecate Railway (Talleyrand Terminal Railroad) | | | RSRV |
| 10030 | TTR | TALLEYRAND TERMINAL RAILROAD COMPAN | | | SCAC4 |
| 10031 | TTR | TTR: Tramvia Torino Rivoli | | I | TRAFFIC |
| 10032 | TTR | TRADE TRANS RAILLOGISTICS SA | | RO | VKM |
| 10033 | TTRA | T'S TRANSPORT | | | SCAC4 |
| 10034 | TTRC | Toronto Transit Comission | Real: TTC | CDN | TRAFFIC |
| 10035 | TTRD | TIGER TRANSPORT | | | SCAC4 |
| 10036 | TTRH | T T R TRANSPORT | | | SCAC4 |
| 10037 | TTRI | TIA TRUCKING | | | SCAC4 |
| 10038 | TTRJ | TANIS TRUCKING COMPANY | | | SCAC4 |
| 10039 | TTRK | TANK TRUCK TRANSPORT INC | | | SCAC4 |
| 10040 | TTRL | TOTAL TRANSPORT & RIGGING INC | | | SCAC4 |
| 10041 | TTRM | TRINITY TRANSPORTS | | | SCAC4 |
| 10042 | TTRP | T TRANSPORTATION, INC | | | SCAC1 |
| 10043 | TTRP | T TRANSPORTATION INC | | | SCAC4 |
| 10044 | TTRR | TRANSPORTES TERRESTRES VALDEZ S A | | | SCAC4 |
| 10045 | TTRT | TOKYO TRANSPORT CORP | | | SCAC4 |
| 10046 | TTRU | TROPICAL SHIPPING AND CONSTRUCTION CO LTD | | | PWRC |
| 10047 | TTRU | Tropical Shipping and Construction Limited | | | RSRV |
| 10048 | TTRU | TROPICAL SHIPPING & CONSTRUCTION CO | | | SCAC4 |
| 10049 | TTRV | Transtriumph Holding | City: Varna | BG | TRAFFIC |
| 10050 | TTRX | Trailer Train Co. | added 4/1968; 10/1968-1/1980; eliminated 1/1992 | | NAKINA |
| 10051 | TTRX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 10052 | TTRX | Trailer Train Co. | added 4/1968 | | NAKINA |
| 10053 | TTRX | Trailer Train Co. (89'3"" or over FA flats equipped with tri-level automobile carrying superstructure furnished by member railroads. Cars are not equipped with hitches and bridge plates. Equipped with hydraulic draft gears) | 10/1968 | | NAKINA |
| 10054 | TTRX | Trailer Train Co. (flat cars, 89'4"" or over, equipped with fixed tri-level auto racks furnished by member railroads) | 4/1970 | | NAKINA |
| 10055 | TTRX | Trailer Train Co./TTX Co. (flat cars, equipped with fixed tri-level auto racks furnished by participant railroads) | 1/1975-1/1994 | | NAKINA |
| 10056 | TTRX | TTX Co. (skeletonized, 3-unit, articulated all-purpose car for use between lift-on/lift-off facilities only. Each unit (platform) is capable of carrying 3-28'6"" trailers, or one trailer up to 57' long, or one container 40' to 53' long) | 7/2000 | | NAKINA |
| 10057 | TTRX | Trailer Train Co. | added 4/68 | | NRHS |
| 10058 | TTRX | Trailer Train Co. (89'3" or over FA flats equipped with tri-level automobile carrying superstructure furnished by member railroads. Cars are not equipped with hitches and bridge plates. Equipped with hydraulic draft gears) | Oct-68 | | NRHS |
| 10059 | TTRX | Trailer Train Co. | Apr-70 | | NRHS |
| 10060 | TTRX | Trailer Train Co. (flat cars, equipped with fixed tri-level auto racks furnished by participant railroads) | 1/75-1/80 | | NRHS |
| 10061 | TTRX | Trailer Train Co. | eliminated 1/92 | | NRHS |
| 10062 | TTRX | TTX Co. | added 1/92; 1/94 | | NRHS |
| 10063 | TTRX | TTX Co. (skeletonized, 3-unit, articulated all-purpose car for use between lift-on/lift-off facilities only. Each unit (platform) is capable of carrying 3-28'6" trailers, or one trailer up to 57' long, or one container 40' to 53' long) | Jul-00 | | NRHS |
| 10064 | TTRX | TTX COMPANY {TRAILER TRAIN COMPANY} | | | PWRC |
| 10065 | TTRX | Trailer Train (TTX Corporation) | | | RSRV |
| 10066 | TTRX | TTX COMPANY | | | SCAC4 |
| 10067 | TTRZ | *TEAM TRACK | | | PWRC |
| 10068 | TTRZ | *TRAIN TRAILER RENTALS LIMITED | | | PWRC |
| 10069 | TTRZ | Train Trailer Rentals Limited | | | RSRV |
| 10070 | TTRZ | TRAIN TRAILER RENTALS, LTD. | | | SCAC4 |
| 10071 | TTS | Transporte Aereo Techico Ejecutivo, S.A. de C.V. | Callsign: Tecnico, | MEX | AVCODES |
| 10072 | TTS | T.A.S.D. (Transporti Aerei Speciali) | | I | AVCODES |
| 10073 | TTS | Transporte Aereo Tecnico Ejecutivo | | | ICAO1 |
| 10074 | TTS | TRANSPORT TRADE SERVICES SA | | RO | VKM |
| 10075 | TTSA | TRANSPORTADORA TAURUS S A DE C V | | | SCAC4 |
| 10076 | TTSC | TRANSPORTES SICA | | | SCAC4 |
| 10077 | TTSE | TRANSPORTES SERRANO | | | SCAC4 |
| 10078 | TTSF | TRAILER TRANSFER SERVICE INC | | | SCAC4 |
| 10079 | TTSH | TOTAL SHIPPING LINE CORP | | | SCAC4 |
| 10080 | TTSJ | TTS | | | SCAC4 |
| 10081 | TTSL | TTMI SARL | | | SCAC4 |
| 10082 | TTSM | TAMEZ TREVINO, SAMUEL | | | SCAC4 |
| 10083 | TTSO | TRANSPORT S R O INC | | | SCAC4 |
| 10084 | TTSPA | Trentino Transporti | | I | TRAFFIC |
| 10085 | TTSQ | TRI STATE DRAYAGE LLC | | | SCAC4 |
| 10086 | TTSS | TOTAL SERVICES INC | | | SCAC4 |
| 10087 | TTST | TORUS TRAFFIC SYSTEMS LTD | | | SCAC4 |
| 10088 | TTSU | LLC TRADETRANS | | RUS | BIC |
| 10089 | TTSV | TEMPLE TRUCKING SERVICE | | | SCAC4 |
| 10090 | TTSW | TECHNI-LITE SYSTEMS INC | | | SCAC4 |
| 10091 | TTSX | Trailer Train Co. | 4/1970; added 1/1974; 1/1975-1/1980; eliminated 1/1992 | | NAKINA |
| 10092 | TTSX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 10093 | TTSX | Trailer Train Co. | 4/1970; added 1/1974 | | NAKINA |
| 10094 | TTSX | Trailer Train Co. (flat cars, equipped with Stac-Pac superstructure furnished by participant railroads) | 1/1975 | | NAKINA |
| 10095 | TTSX | Trailer Train Co./TTX Co. (flat cars equipped with coverless enclosed bi-level furnished by participant railroads) | 1/1980-7/2000 | | NAKINA |
| 10096 | TTSX | Trailer Train Co. | 4/70; added 1/74 | | NRHS |
| 10097 | TTSX | Trailer Train Co. (flat cars, equipped with Stac-Pac superstructure furnished by participant railroads) | Jan-75 | | NRHS |
| 10098 | TTSX | Trailer Train Co. (flat cars equipped with coverless enclosed bi-level furnished by participant railroads) | 1/80; eliminated 1/92 | | NRHS |
| 10099 | TTSX | TTX Co. (flat cars equipped with coverless enclosed bi-level furnished by participant railroads) | added 1/92; 1/94-7/2000 | | NRHS |
| 10100 | TTSX | TTX COMPANY {TRAILER TRAIN COMPANY} | | | PWRC |
