| 1 | ONW | Oregon & Northwestern R.R. Co. | 1/1975; added 4/1979; 1/1980; eliminated 4/1989; eliminated 4/1990 | | NAKINA |
| 2 | ONW | Oregon & Northwestern R.R. Co. | 1/75; added 4/79; 1/80; eliminated 4/89; eliminated 4/90 | | NRHS |
| 3 | ONW | OREGON & NORTHWESTERN RAILROAD CO. | | | PWRC |
| 4 | ONW | Oregon and Northwestern Railroad | | | RSRV |
| 5 | ONWC | ON WHEEL CARRIER | | | SCAC4 |
| 6 | ONWH | ONEILL & WHITAKER INC | | | SCAC3 |
| 7 | ONWH | ONEIDA WAREHOUSING LLC | | | SCAC4 |
| 8 | ONWQ | O & W TRUCK LINES | | | SCAC3 |
| 9 | ONWR | Oregon & Northwestern Railroad | | USA | TRAFFIC |
| 10 | ONWY | ONE WAY TRANSPORTATION INC | | | SCAC4 |
