| 1 | NPR | Air Napier | Callsign: Air Napier, | NZ | AVCODES |
| 2 | NPR | Air Napier | | | ICAO1 |
| 3 | NPR | Northern Plains R.R., Inc. | 7/2000-7/2005 | | NAKINA |
| 4 | NPR | Northern Plains R.R., Inc. | Jul-00 | | NRHS |
| 5 | NPR | NORTHERN PLAINS RAILROAD | | | PWRC |
| 6 | NPR | Northern Plains Railroad | | | RSRV |
| 7 | NPR | NORTHERN PLAINS RAILROAD INC | | | SCAC4 |
| 8 | NPR | Northern Plains Railroad | | USA | TRAFFIC |
| 9 | NPRB | Northern Pacific Ry. | 10/1957-7/1965 | | NAKINA |
| 10 | NPRB | Northern Pacific Ry. | 10/57-7/65 | | NRHS |
| 11 | NPRB | BURLINGTON NORTHERN RAILROAD CO [NORTHERN PACIFIC RY] | | | PWRC |
| 12 | NPRC | NEWPORT CARRIERS INC | | | SCAC4 |
| 13 | NPRD | NORTHERN PRIDE INC | | | SCAC4 |
| 14 | NPRI | NATIONAL PAPER RECYCLING INC | | | SCAC4 |
| 15 | NPRL | NIAGARA PALLET & RECYCLERS LTD | | | SCAC4 |
| 16 | NPRO | NAPIER, RONDELL | | | SCAC3 |
| 17 | NPRS | NEWSPRESS | | | SCAC4 |
| 18 | NPRT | NI PRODUITS | | | SCAC4 |
| 19 | NPRU | Sea Star Line | | | RSRV |
| 20 | NPRU | SEA STAR LINE LLC | | | SCAC4 |
| 21 | NPRW | NETTLES, PERCY W | | | SCAC3 |
| 22 | NPRX | Canadian Northern Railway, LLC | 7/2005 (not listed) | | NAKINA |
| 23 | NPRX | Neuhoff Packing Co. | 7/1923-7/1932 | | NAKINA |
| 24 | NPRX | Yakima Interurban Lines Assn. | 7/2000 (not listed) | | NAKINA |
| 25 | NPRX | Yakima Interurban Lines Assn. | Jul-00 | | NRHS |
| 26 | NPRX | *NEUHOFF PACKING CO. | | | PWRC |
| 27 | NPRX | *YAKIMA INTERURBAN LINES ASSOCIATION | | | PWRC |
| 28 | NPRX | +CANADIAN NORTHERN RAILWAY, LLC | | | PWRC |
| 29 | NPRX | Yakima Interurban Lines Association | | | RSRV |
| 30 | NPRX | CANADIAN NORTHERN RAILWAY LLC | | | SCAC4 |
