| 1 | BTTX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 2 | BTTX | Trailer Train Co. | added 1/1961; 4/1961-1/1980; eliminated 1/1992 | | NAKINA |
| 3 | BTTX | Trailer Train Co. (not defined) | added 1/1961; 4/1961 | | NAKINA |
| 4 | BTTX | Trailer Train Co. (FCS flat cars equipped with bi-level automobile carrying superstructures furnished by member railroads. Cars are not equipped with hitches and bridge plates) | 4/1963 | | NAKINA |
| 5 | BTTX | Trailer Train Co. (FA flat cars equipped with bi-level automobile carrying superstructures furnished by member railroads. Cars are not equipped with hitches and bridge plates) | 7/1965-10/1968 | | NAKINA |
| 6 | BTTX | Trailer Train Co. (Flat cars, equipped with bi-level auto racks furnished by participant railroads) | 4/1970-7/1985 | | NAKINA |
| 7 | BTTX | Trailer Train Co./TTX Co. (not defined) | 10/1991-1/1992 | | NAKINA |
| 8 | BTTX | TTX Co. (140 ft. intregal articulated bi-level auto rack with end of car cush.) | 7/2000 | | NAKINA |
| 9 | BTTX | Trailer Train Co. | 4/61-7/65 | | NRHS |
| 10 | BTTX | Trailer Train Co. (FA flat cars equipped with bi-level automobile carrying superstructures furnished by member railroads. Cars are not equipped with hitches and bridge plates) | 10/66-10/68 | | NRHS |
| 11 | BTTX | Trailer Train Co. | Apr-70 | | NRHS |
| 12 | BTTX | Trailer Train Co. (Flat cars, equipped with bi-level auto racks furnished by participant railroads) | 1/75-1/80 | | NRHS |
| 13 | BTTX | Trailer Train Co. | eliminated 1/92 | | NRHS |
| 14 | BTTX | TTX Co. | added 1/92 | | NRHS |
| 15 | BTTX | TTX Co. (140 ft. intregal articulated bi-level auto rack with end of car cush.) | Jul-00 | | NRHS |
| 16 | BTTX | TTX COMPANY - TRAILER TRAIN CO. | | | PWRC |
| 17 | BTTX | Trailer Train (TTX Corporation) | | | RSRV |
| 18 | BTTX | TTX COMPANY | | | SCAC4 |
