| Abbreviation | Definition |
|---|---|
| RLTX | Randolph L. Johnston |
| RLW | Republic Locomotive Works |
| RLY | Railway |
| RM | Rail Me |
| RMAX | Rocky Mountain Rail Society |
| RMC | Rail Motor Car |
| RMCU | RMC ( Trancoleasing) Limited |
| RMCU | RMC (Trancoleasing) Limited |
| RMCU | RMC Trancoleasing |
| RMCX | Reynolds Metals |
| RMCX | Reynolds Metals Company |
| RMDX | American Refrigerator Transit |
| RMDX | American Refrigerator Transit Company |
| RMF | Rail Miniature Flash |
| RMG | rail mounted gantry |
| RMGX | Railcar Limited |
| RMI | Railway Mechanics Institute |
| RMIU | Mi Environmental Services |
| RMIU | Railway Mazdoor Ittehad Union |
| RMIX | Ready Mix Concrete |