| 1 | WPMC | WESTERN POLYMER CORP | | | SCAC4 |
| 2 | WPMI | WILLIS PERMIAN MOVERS INC | | | SCAC4 |
| 3 | WPMU | UNION PACIFIC RAILROAD COMPANY | | | PWRC |
| 4 | WPMU | Western Pacific Railroad (Union Pacific Railroad) | | | RSRV |
| 5 | WPMW | Western Pacific R.R. Co. | added 1/1984; eliminated 10/1987 | | NAKINA |
| 6 | WPMW | Union Pacific R.R. Co. | added 10/1987; 1/1994-7/2005 | | NAKINA |
| 7 | WPMW | Western Pacific R.R. Co. | eliminated 10/87 | | NRHS |
| 8 | WPMW | Union Pacific R.R. Co. | added 10/87; 1/94-7/2000 | | NRHS |
| 9 | WPMW | UNION PACIFIC RAILROAD CO. [WESTERN PACIFIC RR.] (MAINTENANCE OF WAY EQUIPMENT) | | | PWRC |
| 10 | WPMW | Western Pacific Railroad (Union Pacific Railroad) | | | RSRV |
| 11 | WPMW | WINNIPEG PATTERN & MODEL WORKS LTD | | | SCAC4 |