| Abbreviation | Definition |
|---|---|
| TMTU | P and O Tank Masters (Gcatainer) |
| TMTZ | Trailer Marine Transport Corporation |
| TN | Texas and Northern Railway |
| TN | Texas and Northern Railway Company |
| TNAX | TransAmerican Refining Corporation |
| TNCX | General Electric Railcar Services Corporation |
| TNCX | North American Car Corp (GE Rail Services) |
| TNER | Texas Northeastern Division Mid- Michigan Railroad Incorporated |
| TNER | Texas Northeastern Division Mid-Michigan Railroad |
| TNHR | Three Notch Railroad |
| TNIU | Areva Inc. |
| TNJ | Toronto & Nipissing Railway |
| TNM | Missouri Pacific Railroad |
| TNM | Union Pacific Railroad Company |
| TNMR | Texas and New Mexico Division Austin and Northwestern Railroad Company Limited |
| TNMR | Texas-New Mexico Railroad (Austin and Northwestern Railroad) |
| TNO | Texas and New Orleans Railroad (Union Pacific Railroad) |
| TNR | Kansas City Southern Railway |
| TNR | Kansas City Southern Railway Company |
| TNSR | Nashtown and Southern Railroad (Lorraine, Eastern and Pacific Railroad) |