| 1 | TTRX | Trailer Train Co. | added 4/1968; 10/1968-1/1980; eliminated 1/1992 | | NAKINA |
| 2 | TTRX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 3 | TTRX | Trailer Train Co. | added 4/1968 | | NAKINA |
| 4 | TTRX | Trailer Train Co. (89'3"" or over FA flats equipped with tri-level automobile carrying superstructure furnished by member railroads. Cars are not equipped with hitches and bridge plates. Equipped with hydraulic draft gears) | 10/1968 | | NAKINA |
| 5 | TTRX | Trailer Train Co. (flat cars, 89'4"" or over, equipped with fixed tri-level auto racks furnished by member railroads) | 4/1970 | | NAKINA |
| 6 | TTRX | Trailer Train Co./TTX Co. (flat cars, equipped with fixed tri-level auto racks furnished by participant railroads) | 1/1975-1/1994 | | NAKINA |
| 7 | TTRX | TTX Co. (skeletonized, 3-unit, articulated all-purpose car for use between lift-on/lift-off facilities only. Each unit (platform) is capable of carrying 3-28'6"" trailers, or one trailer up to 57' long, or one container 40' to 53' long) | 7/2000 | | NAKINA |
| 8 | TTRX | Trailer Train Co. | added 4/68 | | NRHS |
| 9 | TTRX | Trailer Train Co. (89'3" or over FA flats equipped with tri-level automobile carrying superstructure furnished by member railroads. Cars are not equipped with hitches and bridge plates. Equipped with hydraulic draft gears) | Oct-68 | | NRHS |
| 10 | TTRX | Trailer Train Co. | Apr-70 | | NRHS |
| 11 | TTRX | Trailer Train Co. (flat cars, equipped with fixed tri-level auto racks furnished by participant railroads) | 1/75-1/80 | | NRHS |
| 12 | TTRX | Trailer Train Co. | eliminated 1/92 | | NRHS |
| 13 | TTRX | TTX Co. | added 1/92; 1/94 | | NRHS |
| 14 | TTRX | TTX Co. (skeletonized, 3-unit, articulated all-purpose car for use between lift-on/lift-off facilities only. Each unit (platform) is capable of carrying 3-28'6" trailers, or one trailer up to 57' long, or one container 40' to 53' long) | Jul-00 | | NRHS |
| 15 | TTRX | TTX COMPANY {TRAILER TRAIN COMPANY} | | | PWRC |
| 16 | TTRX | Trailer Train (TTX Corporation) | | | RSRV |
| 17 | TTRX | TTX COMPANY | | | SCAC4 |
