| Abbreviation | Definition |
|---|---|
| RBCU | Rail-Bridge Corporation (RB Holding) |
| RBCX | Rail-Bridge Corporation |
| RBLX | Brent C. Lewis |
| RBMN | Reading Blue Mountain and Northern Railroad |
| RBMN | Reading Blue Mountain and Northern Railroad Company |
| RBNX | Fruit Growers Express |
| RBO | Roanoke, Belmont, & Occidental Railroad |
| RBOX | Railbox (TTX Corporation) |
| RBOX | Railbox Company |
| RBT | Rail Barge Truck |
| RBW | BNSF Railway |
| RBWX | Western Fruit Express |
| RC | Railway Cutting |
| RC | Rosslyn Connecting Railroad |
| RC&T | Riverdale, Calumet, & Thornton |
| RCCX | Relco Nevada Corporation |
| RCF | Rail Coach Factory |
| RCFU | Reebok International |
| RCH | Railway Clearing House |
| RCIZ | Radich Construction |