| Abbreviation | Definition |
|---|---|
| GRPX | General Chemical (Soda Ash) Partners |
| GRR | Georgetown Railroad |
| GRR | Georgetown Railroad Company |
| GRRX | Good Rich Refining (Wampum Hardware) |
| GRRX | Wampum Hardware |
| GRS | Guilford Rail System |
| GRSX | Gunderson Rail Services |
| GRTX | Savage-Tolk Energy Services |
| GRTX | Wheelabrator Coal Services Company |
| GRWR | Great Walton Railroad |
| GRWR | Great Walton Railroad Company |
| GRYR | Grenada Railway |
| GRYX | John H. Grace (Transmatrix) |
| GRYX | John H. Grace Company |
| GSAX | Granite State Concrete |
| GSCU | Eurotainer U.S. Incorporated |
| GSCU | Eurotainer US |
| GSCX | GATX/ GLC Leasing Corporation |
| GSCX | Greenville Leasing (GATX) |
| GSF | Georgia Southern and Florida Railway |