| 1 | GTT | Gruppo Trasporti Torinesi | | I | TRAFFIC |
| 2 | GTT | Gruppo Torinese Trasporti | | IT | VKM |
| 3 | GTTC | GOLDEN TOUCH TRANSPORTATION LLC | | | SCAC4 |
| 4 | GTTD | G & R TRUCKING CO INC | | | SCAC4 |
| 5 | GTTE | GARNETT, T E INC | | | SCAC4 |
| 6 | GTTF | GOETTSCH FARMS | | | SCAC4 |
| 7 | GTTI | GO-TO TRANSPORT INC | | | SCAC4 |
| 8 | GTTJ | G &T TRUCKING INC | | | SCAC4 |
| 9 | GTTL | GANTRY TRUCKING LTD | | | SCAC4 |
| 10 | GTTM | GUTTMAN OIL COMPANY | | | SCAC4 |
| 11 | GTTN | GATE TRANSPORTATION LLC | | | SCAC4 |
| 12 | GTTT | G TWO THOUSAND (G2000) EXPRESS INC | | | SCAC4 |
| 13 | GTTU | GETRAS SRL | | I | BIC |
| 14 | GTTU | GTT GEMEINSCHAFTS TANK TRANSPORT AG | | | SCAC4 |
| 15 | GTTX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 16 | GTTX | Trailer Train Co. | added 1/1964; 7/1965-1/1980; eliminated 1/1992 | | NAKINA |
| 17 | GTTX | Trailer Train Co. (FC flat cars equipped with hitches and bridge plates for the transportation of trailers and manufactured by GATC) | 7/1965-10/1968 | | NAKINA |
| 18 | GTTX | Trailer Train Co. (Flat cars, equipped with hitches and bridge plates for the transportation of trailers. Cars built by GATC) | 4/1970-7/1985 | | NAKINA |
| 19 | GTTX | Trailer Train Co./TTX Co. (89' flat cars that have been modified for autorack services that have not been racked) | 10/1991-1/1994 | | NAKINA |
| 20 | GTTX | TTX Co. (89 ft. flat cars that have been modified for autorack service that have not been racked, equipped with end of car cush.) | 7/2000 | | NAKINA |
| 21 | GTTX | Trailer Train Co. | Jul-65 | | NRHS |
| 22 | GTTX | Trailer Train Co. (FC flat cars equipped with hitches and bridge plates for the transportation of trailers and manufactured by GATC) | 10/66-10/68 | | NRHS |
| 23 | GTTX | Trailer Train Co. | Apr-70 | | NRHS |
| 24 | GTTX | Trailer Train Co. (Flat cars, equipped with hitches and bridge plates for the transportation of trailers. Cars built by GATC) | 1/75-1/80 | | NRHS |
| 25 | GTTX | Trailer Train Co. | eliminated 1/92 | | NRHS |
| 26 | GTTX | TTX Co. | added 1/92 | | NRHS |
| 27 | GTTX | TTX Co. (89' flat cars that have been modified for autorack services that have not been racked) | Jan-94 | | NRHS |
| 28 | GTTX | TTX Co. (89 ft. flat cars that have been modified for autorack service that have not been racked, equipped with end of car cush.) | Jul-00 | | NRHS |
| 29 | GTTX | TTX COMPANY | | | PWRC |
| 30 | GTTX | Trailer Train (TTX Corporation) | | | RSRV |
| 31 | GTTX | TTX COMPANY | | | SCAC4 |
| 32 | GTTY | GUTTY TRUCKING LLC | | | SCAC4 |
| 33 | GTTZ | GT TRUCKING INC | | | SCAC4 |
