| 1 | DRG | Italair S.p.A. | IATA: B8, Callsign: Italair, Ceased operations 09/2000 | I | AVCODES |
| 2 | DRG | DENVER & RIO GRANDE RAILROAD | | | PWRC |
| 3 | DRG | Denver and Rio Grande Railroad | | | RSRV |
| 4 | DRG | Deutsche Reichsbahn-Gesellschaft ( - 1945) | | D | TRAFFIC |
| 5 | DRGC | DRAGE, GARY INC | | | SCAC4 |
| 6 | DRGE | D R G EXPRESS LLP | | | SCAC4 |
| 7 | DRGK | DONE RIGHT TRUCKING | | | SCAC4 |
| 8 | DRGL | DYNAMIC RESOURCES GROUP TECATE LLC | | | SCAC4 |
| 9 | DRGM | DISTINCTIVE DECOR LTD | | | SCAC4 |
| 10 | DRGO | DRAGOONS FARM EQUIPMENT INC | | | SCAC4 |
| 11 | DRGP | DRAGON TRANSPORT LTD | | | SCAC4 |
| 12 | DRGQ | D R TRANSPORTATION INC | | | SCAC4 |
| 13 | DRGR | Denver & Rio Grande R.R. Co. | added 7/2008; eliminated 4/2009 | | NAKINA |
| 14 | DRGR | DENVER & RIO GRANDE RAILROAD CO. | | | PWRC |
| 15 | DRGR | DENVER & RIO GRANDE RAILROAD COMPAN | | | SCAC4 |
| 16 | DRGS | DARGUS TRANSPORTATION INC. | | | PWRC |
| 17 | DRGT | DTI | | | SCAC4 |
| 18 | DRGW | Union Pacific R.R. Co. | added 7/1997; 7/2000-7/2005 | | NAKINA |
| 19 | DRGW | Denver & Rio Grande Western R.R. Co. | 1/1975-1/1994; eliminated 7/1997 | | NAKINA |
| 20 | DRGW | (D&RGW) Denver & Rio Grande Western R.R. Co. | 4/1970 | | NAKINA |
| 21 | DRGW | (D&RGW) Denver & Rio Grande Western R.R. Co. | Apr-70 | | NRHS |
| 22 | DRGW | Denver & Rio Grande Western R.R. Co. | 1/75-1/94; eliminated 7/97 | | NRHS |
| 23 | DRGW | Union Pacific R.R. Co. | added 7/97; 7/2000 | | NRHS |
| 24 | DRGW | UP [SP] [DENVER & RIO GRANDE WESTERN] | | | PWRC |
| 25 | DRGW | Denver and Rio Grande Western Railroad (Union Pacific Railroad) | | | RSRV |
| 26 | DRGW | Denver & Rio Grande Western Railroad | | USA | TRAFFIC |
| 27 | DRGX | The Museum of Railway Workers | 7/2005 (not listed) | | NAKINA |
| 28 | DRGX | Denver & Royal Gorge Ry., LLC | 7/2000 (not listed) | | NAKINA |
| 29 | DRGX | Denver & Royal Gorge Ry., LLC | Jul-00 | | NRHS |
| 30 | DRGX | *DENVER & ROYAL GORGE RAILWAY | | | PWRC |
| 31 | DRGX | +MUSEUM OF RAILWAY WORKERS | | | PWRC |
| 32 | DRGX | Denver and Royal Gorge Railway | | | RSRV |
| 33 | DRGX | MUSEUM OF RAILWAY WORKERS, THE | | | SCAC4 |
