| 1 | GRS | Golden Rule Airlines | | | ICAO1 |
| 2 | GRS | GUILFORD RAILROAD SYSTEM | | | PWRC |
| 3 | GRS | Guilford Rail System | Pan Am Railways | USA | TRAFFIC |
| 4 | GRSB | GLEN ROSE TRANSPORTATION | | | SCAC4 |
| 5 | GRSC | GRESS TRUCKING | | | SCAC4 |
| 6 | GRSD | GANADERA REBEIL SPR DE RL | | | SCAC4 |
| 7 | GRSE | GARRISON TRANSPORTATION SERVICES IN | | | SCAC4 |
| 8 | GRSE | Granit Srevices | | FR | VKM |
| 9 | GRSF | GST CORPORATION (INTERMODAL DIVISIO | | | SCAC4 |
| 10 | GRSJ | GROSSMAN, R TRUCKING CO LLC | | | SCAC4 |
| 11 | GRSK | GREENSTATE TRUCKING INC | | | SCAC4 |
| 12 | GRSM | GREAT SMOKEY MOUNTAIN RAILROAD | | | PWRC |
| 13 | GRSM | GRASSMID TRANSPORT | | | SCAC4 |
| 14 | GRSQ | GLOBAL REFRIGERATION SOLUTIONS | | | SCAC4 |
| 15 | GRST | GARST LP GAS INC | | | SCAC4 |
| 16 | GRST | Gräf & Stift | since 2002 subsidiary of MAN | A | TRAFFIC |
| 17 | GRSU | GREEN SEA TRANSPORT LLC | | RUS | BIC |
| 18 | GRSU | GRENCO REEFER SERVICES LTD | | | SCAC4 |
| 19 | GRSV | GRAEBEL RELOCATION SERVICES WORLDWI | | | SCAC4 |
| 20 | GRSW | GRIMSHAW TRUCKING | | | SCAC4 |
| 21 | GRSX | Gunderson Rail Services | added 7/2000; 7/2000-7/2005; eliminated 10/2009 | | NAKINA |
| 22 | GRSX | National Car Co. | 4/1947-1/1952 | | NAKINA |
| 23 | GRSX | National Car Co. | Jan-52 | | NRHS |
| 24 | GRSX | Gunderson Rail Services | added 7/2000; 7/2000 | | NRHS |
| 25 | GRSX | *NATIONAL CAR CO. | | | PWRC |
| 26 | GRSX | *GARLAND RAILROAD SRUR TRACK | | | PWRC |
| 27 | GRSX | +GUNDERSON RAIL SERVICES | | | PWRC |
| 28 | GRSX | Gunderson Rail Services | | | RSRV |
| 29 | GRSX | GUNDERSON RAIL SERVICES | | | SCAC4 |
| 30 | GRSZ | GREATER SOUTHWEST COMPANY | | | PWRC |
