| Abbreviation | Definition |
|---|---|
| GBRX | Greenbrier Leasing Corporation |
| GBRY | Gettysburg Railway |
| GBRZ | Greenbrier Leasing Corporation |
| GBSR | Georgian Bay & Seaboard Railway |
| GBW | Fox Valley and Western Limited |
| GBW | Green Bay and Western Railroad (Canadian National Railway) |
| GBWR | Georgian Bay & Wellington Railway |
| GBWX | Gerber Products (Novartis) |
| GC | Georgia Central Railway |
| GC | Georgia Central Railway L. P. |
| GCAU | G.C.A. Transport |
| GCAU | G.C.A. Transport Limited |
| GCCI | Grade Crossing Collision Investigation |
| GCCX | GATX Capital Corporation |
| GCCX | General American Marks (GATX Corporation) |
| GCCX | General American Marks Company (old - now GATX) |
| GCCZ | Gibson County Co-Op Railroad |
| GCDU | Overseas Container Limited |
| GCDU | Overseas Container Ltd. |
| GCEU | Genstar Container Corporation |