| 1 | JTTX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 2 | JTTX | Trailer Train Co. | added 1/1966; 10/1966-1/1980; eliminated 1/1992 | | NAKINA |
| 3 | JTTX | Trailer Train Co. (FMS flat cars specially modified or equipped by members of Trailer Train Co. with miscellaneous devices for special services) | added 1/1966; 10/1966-10/1968 | | NAKINA |
| 4 | JTTX | Trailer Train Co./TTX Co. (flat cars specially modified or equipped by participant railroads with miscellaneous devices for special services) | 4/1970-1/1994 | | NAKINA |
| 5 | JTTX | TTX Co. (flat cars specially modified or equipped by participant railroads with miscellaneous devices for special services, equipped with end of car cush.) | 7/2000 | | NAKINA |
| 6 | JTTX | Trailer Train Co. (FMS flat cars specially modified or equipped by members of Trailer Train Co. with miscellaneous devices for special services | added 1/66; 10/66-10/68 | | NRHS |
| 7 | JTTX | Trailer Train Co. | Apr-70 | | NRHS |
| 8 | JTTX | Trailer Train Co. (flat cars specially modified or equipped by participant railroads with miscellaneous devices for special services) | 1/75-1/80; eliminated 1/92 | | NRHS |
| 9 | JTTX | TTX Co. (flat cars specially modified or equipped by participant railroads with miscellaneous devices for special services) | added 1/92; 1/94 | | NRHS |
| 10 | JTTX | TTX Co. (flat cars specially modified or equipped by participant railroads with miscellaneous devices for special services, equipped with end of car cush.) | Jul-00 | | NRHS |
| 11 | JTTX | TTX COMPANY | | | PWRC |
| 12 | JTTX | Trailer Train (TTX Corporation) | | | RSRV |
| 13 | JTTX | TTX COMPANY | | | SCAC4 |
