| 10101 | TTSX | Trailer Train (TTX Corporation) | | | RSRV |
| 10102 | TTSX | TTX COMPANY | | | SCAC4 |
| 10103 | TTSZ | TRITON TRANSPORT SERVICES | | | PWRC |
| 10104 | TTSZ | Triton Transport Services | | | RSRV |
| 10105 | TTSZ | TRITON TRANSPORT SERVICES | | | SCAC4 |
| 10106 | TTT | Three T AB | 2001 - | S | svenska-lok.se |
| 10107 | TTT | Three T AB | 2001 - | S | TRAFFIC |
| 10108 | TTT | Three T AB | | SE | VKM |
| 10109 | TTTA | TRI TRUST TRANSPORTATION INC | | | SCAC4 |
| 10110 | TTTC | T T T CO INC | | | SCAC4 |
| 10111 | TTTD | TRANSPORT T E D | | | SCAC4 |
| 10112 | TTTE | T&T TRUCKING, INC | | | SCAC1 |
| 10113 | TTTE | TOTAL TEMPERATURE CONTROL TRANSPORT | | | SCAC4 |
| 10114 | TTTF | TRENTON TRANSPORTATION SERVICE INC | | | SCAC4 |
| 10115 | TTTJ | T & T TRANSPORT SERVICE INC | | | SCAC4 |
| 10116 | TTTK | TONEYS TRANSPORTATION LLC | | | SCAC4 |
| 10117 | TTTK | Tallina Trammi- ja Trollibussikoondise AS | City: Tallin | EST | TRAFFIC |
| 10118 | TTTM | T ANN T TRUCKING INC | | | SCAC4 |
| 10119 | TTTN | TITAN TRANSPORT LLC | | | SCAC4 |
| 10120 | TTTO | TANTARA TRANSPORTATION CORP | | | SCAC4 |
| 10121 | TTTR | TOTAL TRANSPORTATION TRUCKING INC | | | SCAC4 |
| 10122 | TTTRA | TT-TRANS, s.r.o. | | SK | VKM |
| 10123 | TTTRO | TRADE TRANS TERMINAL SRL | | RO | VKM |
| 10124 | TTTT | TRANSPORT TETREAULT INC | | | SCAC4 |
| 10125 | TTTU | TRANSPORT INTERNATIONAL CONTAINERS S.A. | | | PWRC |
| 10126 | TTTU | Transport International Containers SA | | | RSRV |
| 10127 | TTTU | EUROTAINER SAS | | | SCAC4 |
| 10128 | TTTW | TENNESSEE TRADERS & TECHNICIANS INC | | | SCAC4 |
| 10129 | TTTX | Trailer Train Co. | added 7/1986 | | NAKINA |
| 10130 | TTTX | TTX Co. | added 10/1997; 7/2000-7/2005 | | NAKINA |
| 10131 | TTTX | Trailer Train Co. | added 7/1986 | | NAKINA |
| 10132 | TTTX | TTX Co. | added 10/1997 | | NAKINA |
| 10133 | TTTX | Trailer Train Co. | added 7/86 | | NRHS |
| 10134 | TTTX | TTX Co. | added 10/97 | | NRHS |
| 10135 | TTTX | TTX COMPANY {TRAILER TRAIN COMPANY} | | | PWRC |
| 10136 | TTTX | Trailer Train (TTX Corporation) | | | RSRV |
| 10137 | TTTX | TTX COMPANY | | | SCAC4 |
| 10138 | TTTY | TWIN TIER TRANSPORT SERVICES INC | | | SCAC4 |
| 10139 | TTTZ | *TRANSAMERICAN TRAILER TRANSPORT, INC. | | | PWRC |
| 10140 | TTTZ | *PUERTO RICAN MARITIME AUTHORITY | | | PWRC |
| 10141 | TTTZ | Puerto Rican Maritime Authority | | | RSRV |
| 10142 | TTTZ | PUERTO RICAN MARITIME AUTHORITY | | | SCAC4 |
| 10143 | TTU | TTT Air | Callsign: Valda, | CZ | AVCODES |
| 10144 | TTU | Tantalus Air | Callsign: Tantalus, | CDN | AVCODES |
| 10145 | TTUF | THOMPSON TRANSPORTATION | | | SCAC4 |
| 10146 | TTUG | TOWN TRUCKING LLC | | | SCAC4 |
| 10147 | TTUI | TAYLOR TRUCKING | | | PWRC |
| 10148 | TTUI | THREE (3) TTT TRUCKING | | | SCAC4 |
| 10149 | TTUK | TRANSTAR TRUCKING INC | | | SCAC4 |
| 10150 | TTUL | TENDER TOUCH MOVING COMPANY INC | | | SCAC4 |
| 10151 | TTUN | TTI TRUCKING | | | SCAC4 |
| 10152 | TTUQ | TROPHY TRANSPORT | | | SCAC4 |
| 10153 | TTUT | TNS TRUCKING LTD | | | SCAC4 |
| 10154 | TTUU | TRANSTEC LTD | | RUS | BIC |
| 10155 | TTUU | TRANSTEK LTD | | | SCAC4 |
| 10156 | TTUX | Trailer Train Co. | added 7/1983; eliminated 1/1992 | | NAKINA |
| 10157 | TTUX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 10158 | TTUX | Trailer Train Co./TTX Co. (single platform TOFC cars with single axle trucks and rigid hitch, capable of carrying one trailer 40' to 48' long and up to 102"" wide, with nose-mounted refrigeration unit between lift-on/lift-off facilities only) | added 7/1983; 7/1985-1/1994 | | NAKINA |
| 10159 | TTUX | Trailer Train Co. | eliminated 1/92 | | NRHS |
| 10160 | TTUX | TTX Co. | added 1/92; 1/94 | | NRHS |
| 10161 | TTUX | TTX COMPANY {TRAILER TRAIN COMPANY} | | | PWRC |
| 10162 | TTUX | Trailer Train (TTX Corporation) | | | RSRV |
| 10163 | TTUX | TTX COMPANY | | | SCAC4 |
| 10164 | TTV | T-air Spol s.r.o. | Callsign: Winsky, Part of TTV Group. | CZ | AVCODES |
| 10165 | TTVD | TIAN TIAN FOOD SERVICE | | | SCAC4 |
| 10166 | TTVE | TRANSPORT TWO FOUR SEVEN (247) INDU | | | SCAC4 |
| 10167 | TTVF | TS TRANSPORTATION INC | | | SCAC4 |
| 10168 | TTVI | TRANSPORT VIA | | | SCAC4 |
| 10169 | TTVJ | TRANSPORTES TFC | | | SCAC4 |
| 10170 | TTVJ | Tinglev-Tonder Veteran Jernbane | | DK | TRAFFIC |
| 10171 | TTVL | TEN THOUSAND VILLAGES | | | SCAC4 |
| 10172 | TTVQ | TROYER TRUCKING INC | | | SCAC4 |
| 10173 | TTVS | TRINITY TRANSPORTATION SERVICES INC | | | SCAC4 |
| 10174 | TTVT | TRANSPORTADORA TREDA SA DE CV | | | SCAC4 |
| 10175 | TTVV | TOPSPEED TRANS | | | SCAC4 |
| 10176 | TTVW | THAMMA TRANSPORT | | | SCAC4 |
| 10177 | TTVX | Trailer Train Co. | 1/1975-1/1980; eliminated 1/1992 | | NAKINA |
| 10178 | TTVX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 10179 | TTVX | Trailer Train Co. (flat cars equipped with Vert-A-Pak superstructure, furnished by participant railroads) | 1/1975-1/1980 | | NAKINA |
| 10180 | TTVX | Trailer Train Co./TTX Co. (flat cars, equipped with tri-level auto racks without end doors and with or without roof panels) | 7/1985-1/1994 | | NAKINA |
| 10181 | TTVX | Trailer Train Co. | | | NRHS |
| 10182 | TTVX | Trailer Train Co. (flat cars equipped with Vert-A-Pak superstructure, furnished by participant railroads) | 1/75-1/80 | | NRHS |
| 10183 | TTVX | Trailer Train Co. | eliminated 1/92 | | NRHS |
| 10184 | TTVX | TTX Co. | added 1/92; 1/94 | | NRHS |
| 10185 | TTVX | TTX COMPANY {TRAILER TRAIN COMPANY} | | | PWRC |
| 10186 | TTVX | Trailer Train (TTX Corporation) | | | RSRV |
| 10187 | TTVX | TTX COMPANY | | | SCAC4 |
| 10188 | TTW | Tiger Airways Taiwan Co. Ltd. | IATA: IT, Callsign: Smart Cat, IATA Prefix: 608, | RC | AVCODES |
| 10189 | TTWA | TEAM TUNDRA WILDLIFE ARTISTS CANADA | | | SCAC4 |
| 10190 | TTWE | TYLERS TRUCKING INC | | | SCAC4 |
| 10191 | TTWG | TRIPLE T TOWING & TRANSPORT INC | | | SCAC4 |
| 10192 | TTWI | TRANSTWINS INTERNATIONAL | | | SCAC4 |
| 10193 | TTWK | TUMINOS TOWING INC | | | SCAC4 |
| 10194 | TTWN | TEDS TOWING | | | SCAC4 |
| 10195 | TTWQ | TTC CARRIERS INC | | | SCAC4 |
| 10196 | TTWR | TWO TWO FOUR THREE SIX FIVE NINE (2 | | | SCAC4 |
| 10197 | TTWU | CANADIAN NATIONAL | | | PWRC |
| 10198 | TTWU | Canadian National Railway | | | RSRV |
| 10199 | TTWW | TRUCKLAND TRANSPORT INC | | | SCAC4 |
| 10200 | TTWX | Trailer Train Co. | added 10/1982; eliminated 1/1992 | | NAKINA |
