| Abbreviation | Definition |
|---|---|
| MTLX | Metal Link International |
| MTMU | March Limited |
| MTMX | Modern Track Machinery |
| MTNX | Rocky Mountain Transportation Services |
| MTPX | Montana Power |
| MTPX | Montana Power Company |
| MTR | Mass Transit Railway |
| MTR | Montour Railroad (Youngstown and Southern Railway) |
| MTR | Youngstown and Southern Railway Company |
| MTRCL | Mass Transit Railway Corporation Limited |
| MTRJF | Mass Transit Railway |
| MTRU | TAL International |
| MTRX | TransMatrix |
| MTRX | TransMatrix Incorporated |
| MTS | Multi Train System |
| MTSU | Marine Transport Service |
| MTSU | Marine Transport Service, Inc. |
| MTTX | Trailer Train (TTX Corporation) |
| MTTX | TTX Company |
| MTUU | MTU Onsite Energy Corporation |