| Abbreviation | Definition |
|---|---|
| MSQU | Military Sealift Command |
| MSQU | U.S. Department of Defense - Military Sealift Command Bayonne NJ |
| MSR | Miniature Square Rail |
| MSR | Minnesota Southern Railway |
| MSR | Mississippi Southern Railroad (Watco) |
| MSRC | Kansas City Southern Railway Company |
| MSRC | MidSouth Railcorp (Kansas City Southern Railway) |
| MSRW | Mississippian Railway Cooperative |
| MSRW | Mississippian Railway Cooperative Incorporated |
| MSS | Manassas Station (Virginia Railway Express- AMTK) |
| MSTL | Minneapolis and St. Louis Railway |
| MSTL | Minneapolis and St. Louis Railway (Union Pacific Railroad) |
| MSTL | Union Pacific Railroad Company, Minneapolis and St. Louis Railway segment |
| MSTR | Massena Terminal Railroad |
| MSTR | Massena Terminal Railroad Company |
| MSTS | MicroSoft Train Simulator |
| MSUU | M/S Containers |
| MSUU | USPCI Incorporated |
| MSV | Mississippi and Skuna Valley Railroad |
| MSV | Mississippi and Skuna Valley Railroad Company |