| 1 | WMR | Western Maryland Railway | Real: WM | USA | TRAFFIC |
| 2 | WMRN | WILMAR & CO | | | SCAC4 |
| 3 | WMRR | WILLIAMS, RICK ENTERPRISES INC | | | SCAC4 |
| 4 | WMRS | WILLIAMS, CARLOS | | | SCAC4 |
| 5 | WMRX | Merchants Despatch Transportation Corp. | added 4/1956; 10/1957-10/1966; eliminated 10/1969 | | NAKINA |
| 6 | WMRX | Merchants Despatch Transportation Corp. | 10/57-10/66; eliminated 10/69 | | NRHS |
| 7 | WMRX | MERCHANTS DESPATCH TRANSPORTATION CORP. | | | PWRC |