| Abbreviation | Definition |
|---|---|
| NAHX | General Electric Railcar Services Corporation |
| NAIR | National Academy of Indian Railways |
| NAIR | National Autonomy of Indian Railways |
| NALU | Norwegian American Lines |
| NALX | Nalco Chemical (NASA Railroad) |
| NALZ | Neptune Orient Lines |
| NALZ | Neptune Orient Lines Limited |
| NAMX | NAMX Leasing |
| NAMX | NAMX Leasing Company |
| NAP | Narragansett Pier Railroad |
| NAP | Narragansett Pier Railroad Company |
| NAPX | North American Plastics |
| NAPX | North American Plastics Incorporated |
| NAR | Canadian National Railway |
| NAR | Northern Alberta Railway (Canadian National Railway) |
| NARA | North American Rail Alliance |
| NARS | National Association of Rail Shippers |
| NARS | North American Rail Shippers |
| NARX | NORCHEM Incorporated |
| NASX | NASA Railroad |