| 1 | PWX | Preway Inc. | 7/1954; added 7/1956; 10/1957-4/1970; eliminated 10/1970 | | NAKINA |
| 2 | PWX | Preway Inc. | added 7/56; 10/57-4/70; eliminated 10/70 | | NRHS |
| 3 | PWX | PREWAY INC. | | | PWRC |
| 4 | PWXE | POWERS EXPRESS | | | SCAC4 |
| 5 | PWXI | POWER TRANSPORT I LLC | | | SCAC4 |
| 6 | PWXN | PACIFIC WAVES XPRESS INC | | | SCAC4 |
| 7 | PWXP | POINT WEST EXPRESS | | | SCAC3 |
| 8 | PWXP | POWELL EXPRESS INC | | | SCAC4 |
| 9 | PWXS | POWELL EXPEDITING SERVICE | | | SCAC3 |
| 10 | PWXT | PUREWAL TRANSPORT | | | SCAC4 |
