| 1 | TTQC | TOTAL CARE LOGISTICS INC | | | SCAC4 |
| 2 | TTQF | TRANSPORTES FLORES | | | SCAC4 |
| 3 | TTQH | THOMAS TRANSPORTATION | | | SCAC4 |
| 4 | TTQL | TRANSPORT TRAILER INC | | | SCAC4 |
| 5 | TTQR | TTR SHIPPING | | | SCAC4 |
| 6 | TTQS | TOTAL TRANSPORTATION SYSTEMS INC | | | SCAC4 |
| 7 | TTQT | TTQ ENTERPRISES INC | | | SCAC4 |
| 8 | TTQW | TRANSRITE TRANSPORTATION SERVICES L | | | SCAC4 |
| 9 | TTQX | Trailer Train Co. | added 4/1991; eliminated 1/1992 | | NAKINA |
| 10 | TTQX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 11 | 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 |
| 12 | 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 |
| 13 | TTQX | Trailer Train Co. | added 4/91; eliminated 1/92 | | NRHS |
| 14 | TTQX | TTX Co. | added 1/92 | | NRHS |
| 15 | 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 |
| 16 | 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 |
| 17 | TTQX | TTX COMPANY {TRAILER TRAIN COMPANY} | | | PWRC |
| 18 | TTQX | Trailer Train (TTX Corporation) | | | RSRV |
| 19 | TTQX | TTX COMPANY | | | SCAC4 |
