| 1 | TTR | Tatra Air | Callsign: Tatra, | SK | AVCODES |
| 2 | TTR | Transportaciones Y Servicios Aereos, S.A. de C.V. | Callsign: Transportaciones, | MEX | AVCODES |
| 3 | TTR | Transportaciones Y Servicios Aereos | | | ICAO1 |
| 4 | TTR | Tijuana & Tecate Ry. Co. | 1/1975-1/1980 | | NAKINA |
| 5 | TTR | Talleyrand Terminal R.R. Co., Inc. | 7/2000-7/2005 | | NAKINA |
| 6 | TTR | Tijuana & Tecate Ry. Co. | 1/75-1/80 | | NRHS |
| 7 | TTR | Talleyrand Terminal R.R. Co., Inc. | Jul-00 | | NRHS |
| 8 | TTR | *TIJUANA & TECATE RAILWAY | | | PWRC |
| 9 | TTR | +TALLEYRAND TERMINAL RAILROAD COMPANY | | | PWRC |
| 10 | TTR | Tijuana and Tecate Railway (Talleyrand Terminal Railroad) | | | RSRV |
| 11 | TTR | TALLEYRAND TERMINAL RAILROAD COMPAN | | | SCAC4 |
| 12 | TTR | TTR: Tramvia Torino Rivoli | | I | TRAFFIC |
| 13 | TTR | TRADE TRANS RAILLOGISTICS SA | | RO | VKM |
| 14 | TTRA | T'S TRANSPORT | | | SCAC4 |
| 15 | TTRC | Toronto Transit Comission | Real: TTC | CDN | TRAFFIC |
| 16 | TTRD | TIGER TRANSPORT | | | SCAC4 |
| 17 | TTRH | T T R TRANSPORT | | | SCAC4 |
| 18 | TTRI | TIA TRUCKING | | | SCAC4 |
| 19 | TTRJ | TANIS TRUCKING COMPANY | | | SCAC4 |
| 20 | TTRK | TANK TRUCK TRANSPORT INC | | | SCAC4 |
| 21 | TTRL | TOTAL TRANSPORT & RIGGING INC | | | SCAC4 |
| 22 | TTRM | TRINITY TRANSPORTS | | | SCAC4 |
| 23 | TTRP | T TRANSPORTATION, INC | | | SCAC1 |
| 24 | TTRP | T TRANSPORTATION INC | | | SCAC4 |
| 25 | TTRR | TRANSPORTES TERRESTRES VALDEZ S A | | | SCAC4 |
| 26 | TTRT | TOKYO TRANSPORT CORP | | | SCAC4 |
| 27 | TTRU | TROPICAL SHIPPING AND CONSTRUCTION CO LTD | | | PWRC |
| 28 | TTRU | Tropical Shipping and Construction Limited | | | RSRV |
| 29 | TTRU | TROPICAL SHIPPING & CONSTRUCTION CO | | | SCAC4 |
| 30 | TTRV | Transtriumph Holding | City: Varna | BG | TRAFFIC |
| 31 | TTRX | Trailer Train Co. | added 4/1968; 10/1968-1/1980; eliminated 1/1992 | | NAKINA |
| 32 | TTRX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 33 | TTRX | Trailer Train Co. | added 4/1968 | | NAKINA |
| 34 | 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 |
| 35 | TTRX | Trailer Train Co. (flat cars, 89'4"" or over, equipped with fixed tri-level auto racks furnished by member railroads) | 4/1970 | | NAKINA |
| 36 | TTRX | Trailer Train Co./TTX Co. (flat cars, equipped with fixed tri-level auto racks furnished by participant railroads) | 1/1975-1/1994 | | NAKINA |
| 37 | 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 |
| 38 | TTRX | Trailer Train Co. | added 4/68 | | NRHS |
| 39 | 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 |
| 40 | TTRX | Trailer Train Co. | Apr-70 | | NRHS |
| 41 | TTRX | Trailer Train Co. (flat cars, equipped with fixed tri-level auto racks furnished by participant railroads) | 1/75-1/80 | | NRHS |
| 42 | TTRX | Trailer Train Co. | eliminated 1/92 | | NRHS |
| 43 | TTRX | TTX Co. | added 1/92; 1/94 | | NRHS |
| 44 | 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 |
| 45 | TTRX | TTX COMPANY {TRAILER TRAIN COMPANY} | | | PWRC |
| 46 | TTRX | Trailer Train (TTX Corporation) | | | RSRV |
| 47 | TTRX | TTX COMPANY | | | SCAC4 |
| 48 | TTRZ | *TEAM TRACK | | | PWRC |
| 49 | TTRZ | *TRAIN TRAILER RENTALS LIMITED | | | PWRC |
| 50 | TTRZ | Train Trailer Rentals Limited | | | RSRV |
| 51 | TTRZ | TRAIN TRAILER RENTALS, LTD. | | | SCAC4 |
