| Abbreviation | Definition |
|---|---|
| NWR | Nashville and Western Railroad |
| NWRX | Niagara and Western Railway (Bergen Passaic Rail) |
| NWTP | North West Taunton Package |
| NWTX | North West Timber |
| NWTX | North West Timber Limited |
| NWTZ | NW Transport |
| NWX | GE Rail Services |
| NWX | General Electric Railcar Services Corporation |
| NWX | Northwest Crossing |
| NWZ | Norfolk and Western Railway (Norfolk Southern) |
| NWZ | Norfolk Southern Railway Company |
| NX | Mathieson Dry Ice |
| NXLZ | National Xpress Logistics |
| NXLZ | National Xpress Logistics Incorporated |
| NYA | New York and Atlantic Railway |
| NYA | New York and Atlantic Railway Company |
| NYAU | N. Y. K. Line |
| NYAU | NYK Line |
| NYBU | N. Y. K. Line |
| NYBU | NYK Line |