| 1 | NWP | Northwestern Pacific R.R. Co. | added 10/1996; eliminated 4/1997; 7/2000 | | NAKINA |
| 2 | NWP | Southern Pacific Transportation Co. | 1/1994 | | NAKINA |
| 3 | NWP | Northwestern Pacific R.R. Co. | 1/1952-10/1966 & 1/1975-1/1980; eliminated 1/1993 | | NAKINA |
| 4 | NWP | Northwestern Pacific R.R. Co. | 1/52-10/66 & 1/75-1/80; eliminated 1/93 | | NRHS |
| 5 | NWP | Southern Pacific Transportation Co. | Jan-94 | | NRHS |
| 6 | NWP | Northwestern Pacific R.R. Co. | added 10/96; eliminated 4/97; 7/2000 | | NRHS |
| 7 | NWP | UNION PACIFIC [SOUTHERN PACIFIC; NORTHWESTERN PACIFIC RR] | | | PWRC |
| 8 | NWP | Northwestern Pacific Railroad (Union Pacific Railroad) | | | RSRV |
| 9 | NWP | NORTHWESTERN PACIFIC RAILROAD COMPA | | | SCAC4 |
| 10 | NWP | Northwestern Pacific Railroad Company | | USA | TRAFFIC |
| 11 | NWP | Lokalbahn Neuenmarkt-Waizenkirchen-Peuerbach | | AT | VKM |
| 12 | NWPA | NORTH-WEST PASSAGE LTD OF HONG KONG | | | SCAC3 |
| 13 | NWPA | NORTH-WEST PASSAGE LTD OF HONG KONG | | | SCAC4 |
| 14 | NWPC | NORTHWEST PERISHABLE SHIPPERS ASSOC | | | SCAC3 |
| 15 | NWPC | NEWMAN EQUIPMENT CO INC | | | SCAC4 |
| 16 | NWPE | NORTHWEST PRODUCE EXPRESS | | | SCAC3 |
| 17 | NWPE | NEW PRIDE CORPORATION | | | SCAC4 |
| 18 | NWPG | NORTH-WEST PASSAGE SHIPPING LTD | | | SCAC3 |
| 19 | NWPI | NEWPORT INTERNATIONAL | | | SCAC3 |
| 20 | NWPN | NOW TRANSPORTATION INC | | | SCAC3 |
| 21 | NWPO | NORTH WEST TRANSPORTATION INC | | | SCAC3 |
| 22 | NWPO | NEW WAVE TRANSPORT | | | SCAC4 |
| 23 | NWPQ | NORTHWEST P & D SERVICE | | | SCAC3 |
| 24 | NWPR | NEW TRANSPORTATION LTD | | | SCAC3 |
| 25 | NWPR | NORTHWEST PROPANE L L C | | | SCAC4 |
| 26 | NWPS | NORTHERN WOODS PRODUCTS SERIVCES (A | | | SCAC3 |
| 27 | NWPT | NEW POINT COMFORT BEACH COMPANY | | | SCAC3 |
| 28 | NWPV | NORTHWEST PROVISIONS INC | | | SCAC4 |
| 29 | NWPX | NEW WAVE POLYMERS, INC. | | | PWRC |
| 30 | NWPX | NEW WAVE POLYMERS INC | | | SCAC4 |
| 31 | NWPZ | NIAGARA OF WISCONSIN PAPER CO. | | | PWRC |
