| 9801 | TTJX | Trailer Train Co./TTX Co. (68', 90-ton flat cars with special tie-down devices, fixtures and stake pockets) | 1/1975-1/1994 | | NAKINA |
| 9802 | TTJX | TTX Co. (68', 90-ton flat cars with special tie-down devices, fixtures and stake pockets, equipped with end of car cush.) | 7/2000 | | NAKINA |
| 9803 | TTJX | Trailer Train Co. | added 4/70; 4/70 | | NRHS |
| 9804 | TTJX | Trailer Train Co. (68', 90-ton flat cars with special tie-down devices, fixtures and stake pockets) | 1/75-1/80; eliminated 1/92 | | NRHS |
| 9805 | TTJX | TTX Co. (68', 90-ton flat cars with special tie-down devices, fixtures and stake pockets) | added 1/92; 1/94 | | NRHS |
| 9806 | TTJX | TTX Co. (68', 90-ton flat cars with special tie-down devices, fixtures and stake pockets, equipped with end of car cush.) | Jul-00 | | NRHS |
| 9807 | TTJX | TTX COMPANY {TRAILER TRAIN COMPANY} | | | PWRC |
| 9808 | TTJX | Trailer Train (TTX Corporation) | | | RSRV |
| 9809 | TTJX | TTX COMPANY | | | SCAC4 |
| 9810 | TTJY | THOMSON TRUCKING INC | | | SCAC4 |
| 9811 | TTK | TTM Korea Co. Ltd | | ROK | AVCODES |
| 9812 | TTKA | TRANS-ACTION INC | | | SCAC4 |
| 9813 | TTKB | TITAN TRUCKING LLC | | | SCAC4 |
| 9814 | TTKD | TIBURON MEDICAL ENT | | | SCAC4 |
| 9815 | TTKE | TORONTO TANK LINES | | | SCAC4 |
| 9816 | TTKG | TOTAL TRUCKING INC | | | SCAC4 |
| 9817 | TTKH | TRIO TRUCKING INC | | | SCAC4 |
| 9818 | TTKI | TROTTER INC | | | SCAC4 |
| 9819 | TTKN | TORRES TRUCKING | | | SCAC4 |
| 9820 | TTKO | T & T TRUCKER INC | | | SCAC4 |
| 9821 | TTKOL | Track Tec Koltram Sp. z o.o. | | PL | VKM |
| 9822 | TTKP | TATKO STONE PRODUCTS | | | SCAC4 |
| 9823 | TTKQ | TTK TRANSPORT INC | | | SCAC4 |
| 9824 | TTKS | TITANIUM TRUCKING SERVICE INC | | | SCAC4 |
| 9825 | TTKT | T N T TRUCKING INC | | | SCAC4 |
| 9826 | TTKU | TRISTAR TRANSPORT LLC | | UAE | BIC |
| 9827 | TTKX | Trailer Train Co. | added 4/1968; 10/1968-1/1980; eliminated 1/1992 | | NAKINA |
| 9828 | TTKX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 9829 | TTKX | Trailer Train Co. | added 4/1968 | | NAKINA |
| 9830 | TTKX | Trailer Train Co. (89'3"" or over FA flats equipped with tri-level automobile carrying superstructures with moveable end sections of second or second and third decks, furnished by member railroads. Cars are not equipped with hitches or bridge plates. Equipped with hydraulic draft gears) | 10/1968 | | NAKINA |
| 9831 | TTKX | Trailer Train Co. (flat cars, 89'4"" or over, equipped with hinged end tri-level auto racks furnished by participant railroads) | 4/1970 | | NAKINA |
| 9832 | TTKX | Trailer Train Co. (flat cars, equipped with hinged end tri-level auto racks furnished by participant railroads) | 1/1975-1/1980 | | NAKINA |
| 9833 | TTKX | Trailer Train Co./TTX Co. (flat cars, equipped with hinged B deck tri-level auto racks furnished by participant railroads) | 7/1985-7/2000 | | NAKINA |
| 9834 | TTKX | Trailer Train Co. | added 4/68 | | NRHS |
| 9835 | TTKX | Trailer Train Co. (89'3" or over FA flats equipped with tri-level automobile carrying superstructures with moveable end sections of second or second and third decks, furnished by member railroads. Cars are not equipped with hitches or bridge plates. Equipped with hydraulic draft gears) | Oct-68 | | NRHS |
| 9836 | TTKX | Trailer Train Co. | Apr-70 | | NRHS |
| 9837 | TTKX | Trailer Train Co. (flat cars, equipped with hinged end tri-level auto racks furnished by participant railroads) | 1/75-1/80 | | NRHS |
| 9838 | TTKX | Trailer Train Co. | eliminated 1/92 | | NRHS |
| 9839 | TTKX | TTX Co. | added 1/92 | | NRHS |
| 9840 | TTKX | TTX Co. (flat cars, equipped with hinged B deck tri-level auto racks furnished by participant railroads) | 1/94-7/2000 | | NRHS |
| 9841 | TTKX | TTX COMPANY {TRAILER TRAIN COMPANY} | | | PWRC |
| 9842 | TTKX | Trailer Train (TTX Corporation) | | | RSRV |
| 9843 | TTKX | TTX COMPANY | | | SCAC4 |
| 9844 | TTL | Total Linhas Aéreas S/A | Callsign: Total, Merged into TRIP Linhas A�reas in May 2008. | BR | AVCODES |
| 9845 | TTL | Total Linhas Aéreas S/A | Callsign: Total, Split from TRIP Linhas A�reas in May 2012. | BR | AVCODES |
| 9846 | TTL | Total Linhas Aereas | | | ICAO1 |
| 9847 | TTL | Thames Trains Ltd. | Real: TT, 1999: 581km standard gauge, not electrified | GB | TRAFFIC |
| 9848 | TTL | TTL Ltd | | BG | VKM |
| 9849 | TTLA | TOTAL TRANSPORTATION LOGISTICS (AGE | | | SCAC4 |
| 9850 | TTLB | TEMPO TRUCKING LLC | | | SCAC4 |
| 9851 | TTLC | TROPICAL TRAILER LEASING CORPORATION | | | PWRC |
| 9852 | TTLC | Tropical Trailer Leasing Corporation | | | RSRV |
| 9853 | TTLC | TOWNSEND TRUCK LINES INC | | | SCAC4 |
| 9854 | TTLE | TOGETHER TRUCKING LLC | | | SCAC4 |
| 9855 | TTLG | TITAN TRANSFER LOGISTICS LLC | | | SCAC4 |
| 9856 | TTLH | TRANS TECH LEASING, INC | | | SCAC1 |
| 9857 | TTLH | TRANS TECH LEASING INC | | | SCAC4 |
| 9858 | TTLI | TAYLOR TRANSPORTATION & LOGISTICS I | | | SCAC4 |
| 9859 | TTLK | T TWO (T2) LOGISTICS INC | | | SCAC4 |
| 9860 | TTLL | TOTAL INTERMODAL SERVICES INC | | | SCAC4 |
| 9861 | TTLN | TMT LINES INC | | | SCAC4 |
| 9862 | TTLO | TRANSPORT LOU GRA INC | | | SCAC4 |
| 9863 | TTLQ | TAYLOR TRUCK LINE INC | | | SCAC4 |
| 9864 | TTLR | T A TRUCKING & LEASING INC | | | SCAC4 |
| 9865 | TTLS | TERMINAL TRANSPORTATION CO INC | | | PWRC |
| 9866 | TTLS | TUBULAR TRANSPORT & LOGISTICS LLC | | | SCAC4 |
| 9867 | TTLU | TOTAL LOGISTICS LTD | | M | BIC |
| 9868 | TTLU | TSINLIEN TRANSPORTATION CO LTD | | | SCAC4 |
| 9869 | TTLW | TITLETOWN EXPRESS INC | | | SCAC4 |
| 9870 | TTLX | Trailer Train Co. | added 1/1983; eliminated 1/1992 | | NAKINA |
| 9871 | TTLX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 9872 | TTLX | Trailer Train Co. (flat cars specially equipped by participant railroads with container pedestals or fixed hitches for assigned corridor intermodal service under the control of assigned participant) | added 1/1983; 7/1985 | | NAKINA |
| 9873 | TTLX | Trailer Train Co./TTX Co. (specially equipped intermodal flatcars) | 10/1991-7/2000 | | NAKINA |
| 9874 | TTLX | Trailer Train Co. | added 1/83; eliminated 1/92 | | NRHS |
| 9875 | TTLX | TTX Co. | added 1/92 | | NRHS |
| 9876 | TTLX | TTX Co. (specially equipped intermodal flatcars) | 1/94-7/2000 | | NRHS |
| 9877 | TTLX | TTX COMPANY {TRAILER TRAIN COMPANY} | | | PWRC |
| 9878 | TTLX | Trailer Train (TTX Corporation) | | | RSRV |
| 9879 | TTLX | TTX COMPANY | | | SCAC4 |
| 9880 | TTLY | TRANSPORTES TALY S A DE C V | | | SCAC4 |
| 9881 | TTLZ | TROPICAL TRAILER LEASING CORPORATION | | | PWRC |
| 9882 | TTLZ | Tropical Trailer Leasing Corporation | | | RSRV |
| 9883 | TTM | Société Tout Transport Mauritanien | Callsign: Tout-Air, | RIM | AVCODES |
| 9884 | TTM | Societe Tout Tranport Mauritanien | | | ICAO1 |
| 9885 | TTMC | TRANSPORTES MC | | | SCAC4 |
| 9886 | TTMD | TRANSPORTES MDR | | | SCAC4 |
| 9887 | TTME | TOP TANKER MANAGEMENT INC | | | SCAC4 |
| 9888 | TTMF | TANGO TRANSPORT LLC (LAFAYETTE DIVI | | | SCAC4 |
| 9889 | TTMH | TAMEZ TAMEZ, HELIODORO | | | SCAC4 |
| 9890 | TTMJ | TEAM TOMLIN INC | | | SCAC4 |
| 9891 | TTMK | TWEEDY TRANSPORT INC | | | SCAC4 |
| 9892 | TTML | T N T MOTOR LINES LTD | | | SCAC4 |
| 9893 | TTMO | TRANSPORTES R MUNOZ | | | SCAC4 |
| 9894 | TTMS | TOTAL TRANSPORTATION INC | | | SCAC1 |
| 9895 | TTMS | TOTAL TRANSPORTATION OF MISSISSIPPI | | | SCAC4 |
| 9896 | TTMU | TITAN MED SARL | | MC | BIC |
| 9897 | TTMU | TTM LEADERLAND BV | | | SCAC4 |
| 9898 | TTMW | TP TRANSPORTATION LLC | | | SCAC4 |
| 9899 | TTMX | Trailer Train Co. | 4/1970; added 4/1971; 1/1975-1/1980; eliminated 1/1992 | | NAKINA |
| 9900 | TTMX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
