| 1 | NPM | Northern Pacific Ry. Co. | 4/1961-10/1966 | | NAKINA |
| 2 | NPM | Northern Pacific Ry. Co. | 4/61-10/66 | | NRHS |
| 3 | NPM | NORTHERN PACIFIC RWY. CO. | | | PWRC |
| 4 | NPMA | NASSAU PRINTING MACHINERY INC | | | SCAC4 |
| 5 | NPMB | Næstved - Præstø - Mern Banen (Præstøbanen) | 1900 - 1961 | DK | jernbanen.dk |
| 6 | NPMB | Næstved - Præstø - Mern Banen (Præstøbanen) | 1900 - 1961 | DK | TRAFFIC |
| 7 | NPMC | NEPTUNE MARITIME CO OF MONROVIA | | | SCAC3 |
| 8 | NPME | NEW PENN MOTOR EXPRESS, INC | | | SCAC3 |
| 9 | NPME | NEW PENN MOTOR EXPRESS, INC | | | SCAC4 |
| 10 | NPMG | NAGLE/POOR MOVING & STORAGE CO INC | | | SCAC3 |
| 11 | NPMI | NORTH PACIFIC MARITIME INC | | | SCAC3 |
| 12 | NPMI | NORTH PACIFIC MARITIME INC | | | SCAC4 |
| 13 | NPMR | NAVY POINT MARINE INC | | | SCAC4 |
| 14 | NPMR | Nevada Pacific | Modell railroad | USA | TRAFFIC |
| 15 | NPMX | Merchants Despatch Transportation Corp. | added 1/1955; 10/1957; eliminated 4/1960 | | NAKINA |
| 16 | NPMX | Merchants Despatch Transportation Corp. | Oct-57 | | NRHS |
| 17 | NPMX | MERCHANTS DESPATCH TRANSPORTATION CORP. | | | PWRC |
