| 1 | D | DampfPlus GmbH | Halle | D | privat-bahn.de |
| 2 | D | Rheinbahn AG | City: Düsseldorf | D | TRAFFIC |
| 3 | D&CI | Des Moines & Central Iowa R.R. | 7/1923-7/1936 | NAKINA | |
| 4 | D&CI | Des Moines & Central Iowa R.R. | 23-Jul | NRHS | |
| 5 | D&CI | DES MOINES & CENTRAL IOWA RAILROAD | PWRC | ||
| 6 | D&D | D & D Eisenbahngesellschaft mbH | Hagenow Land (D&D = Dehns und Dehns) | D | privat-bahn.de |
| 7 | D&H | Delaware and Hudson R.R. Corp. | 1/1941-10/1966 | NAKINA | |
| 8 | D&H | Delaware and Hudson R.R. Corp. | 1/52-10/66 | NRHS | |
| 9 | D&H | CANADIAN PACIFIC RAILWAY [DELAWARE & HUDSON RAILROAD CORP.] | PWRC | ||
| 10 | D&IM | Denver & Intermountain R.R. Co. | 8/1920-1/1946; 1/1952 | NAKINA | |
| 11 | D&IM | Denver & Intermountain R.R. Co. | 7/23-1/52 | NRHS | |
| 12 | D&IM | DENVER & INTERMOUNTAIN RAILROAD CORP. | PWRC | ||
| 13 | D&IR | (The) Duluth & Iron Range R.R. (Co.) | 8/1920-7/1954 | NAKINA | |
| 14 | D&IR | The Duluth & Iron Range R.R. Co. | 23-Jul | NRHS | |
| 15 | D&IR | Duluth & Iron Range R.R. | 4/38-1/52 | NRHS | |
| 16 | D&IR | DULUTH & IRON RANGE RAILROAD CO. | PWRC | ||
| 17 | D&M | Detroit & Mackinac Ry. | 8/1920-4/1961 | NAKINA | |
| 18 | D&M | Detroit & Mackinac Ry. | 7/23-4/61 | NRHS | |
| 19 | D&M | LAKE STATE RAILWAY CO. [DETROIT & MACKINAC RY] | PWRC | ||
| 20 | D&MM | (The) Dansville & Mount Morris R.R. (Co.) | 8/1920-4/1938 | NAKINA | |
| 21 | D&MM | The Dansville & Mount Morris R.R. Co. | 23-Jul | NRHS | |
| 22 | D&MM | Dansville & Mount Morris R.R. Co. | Apr-38 | NRHS | |
| 23 | D&MM | DANSVILLE & MT. MORRIS RAILROAD CO. | PWRC | ||
| 24 | D&N | Delaware & Northern Ry. | 1/1941 | NAKINA | |
| 25 | D&N | Delaware & Northern Ry. (Co.) | 7/1930-4/1938 | NAKINA | |
| 26 | D&N | Delaware & Northern R.R. Co. | 8/1920-7/1923 | NAKINA | |
| 27 | D&N | Delaware & Northern R.R. Co. | 23-Jul | NRHS | |
| 28 | D&N | Delaware & Northern R.R. | Apr-38 | NRHS | |
| 29 | D&N | *DELAWARE & NORTHERN RWY. | PWRC | ||
| 30 | D&N | *NEW YORK CENTRAL [DEXTER & NORTHERN RR] | PWRC | ||
| 31 | D&RG | Denver & Rio Grande Western R.R. Co. | 7/1932 | NAKINA | |
| 32 | D&RG | Denver & Rio Grande Western R.R. System | 7/1923 | NAKINA | |
| 33 | D&RG | Denver & Rio Grande Western R.R. System | 23-Jul | NRHS | |
| 34 | D&RG | DENVER & RIO GRANDE WESTERN RAILROAD | PWRC | ||
| 35 | D&RGW | Denver & Rio Grande Western R.R. (Co.) | 7/1930-10/1966 | NAKINA | |
| 36 | D&RGW | Denver & Rio Grande Western R.R. | 4/38-10/66 | NRHS | |
| 37 | D&RGW | DENVER & RIO GRANDE WESTERN RAILROAD | PWRC | ||
| 38 | D&S | DILLONVALE & SMITHFIELD RWY | PWRC | ||
| 39 | D&SL | Denver & Rio Grande Western R.R. | 4/1961-7/1965 | NAKINA | |
| 40 | D&SL | Denver & Salt Lake Ry. (Co.) | 8/1920-10/1957 | NAKINA | |
| 41 | D&SL | Denver & Salt Lake Ry. Co. | 23-Jul | NRHS | |
| 42 | D&SL | Denver & Salt Lake Ry. | 4/38-10/57 | NRHS | |
| 43 | D&SL | Denver & Rio Grande Western R.R. | 4/61-7/65 | NRHS | |
| 44 | D&SL | *DENVER & SALT LAKE rWY. CO. | PWRC | ||
| 45 | D&SL | *DENVER & RIO GRANDE WESTERN RAILROAD | PWRC | ||
| 46 | D&TS | Detroit & Toledo Shore Line R.R. (Co.) | 8/1920-4/1961 | NAKINA | |
| 47 | D&TS | Detroit & Toledo Shore Line R.R. Co. | 23-Jul | NRHS | |
| 48 | D&TS | Detroit & Toledo Shore Line R.R. | 4/38-4/61 | NRHS | |
| 49 | D&TS | DETROIT & TOLEDO SHORE LINE RAILROAD CO. | PWRC | ||
| 50 | D&W | Danville & Western Ry. | 4/1938-1/1950 | NAKINA | |
| 51 | D&W | Danville & Western Ry. Co. (Southern Ry. System) | 8/1920-7/1936 | NAKINA | |
| 52 | D&W | Danville & Western Ry. (Southern Ry. System) | 23-Jul | NRHS | |
| 53 | D&W | Danville & Western Ry. | Apr-38 | NRHS | |
| 54 | D&W | SOUTHERN RAILWAY {DANVILLE & WESTERN RAILWAY CO.} | PWRC | ||
| 55 | DA | Canadian Pacific Ry. Co. | added 1/1997; 7/2000-7/2005 | NAKINA | |
| 56 | DA | CP Rail System | eliminated 1/1997 | NAKINA | |
| 57 | DA | CP Rail | 1/1994 | NAKINA | |
| 58 | DA | CP Rail (Dominion Atlantic Ry. Co.) | 1/1975-1/1980 | NAKINA | |
| 59 | DA | Dominion Atlantic Ry. Co. | 8/1920-10/1966 | NAKINA | |
| 60 | DA | Dominion Atlantic Ry. Co. | 7/23-10/66 | NRHS | |
| 61 | DA | CP Rail (Dominion Atlantic Ry. Co.) | 1/75-1/80 | NRHS | |
| 62 | DA | CP Rail | Jan-94 | NRHS | |
| 63 | DA | CP Rail System | eliminated 1/97 | NRHS | |
| 64 | DA | Canadian Pacific Ry. Co. | added 1/97; 7/2000 | NRHS | |
| 65 | DA | CP RAIL [DOMINION ATLANTIC RY.] | PWRC | ||
| 66 | DA | Dominion Atlantic Railway (Canadian Pacific Railway) | RSRV | ||
| 67 | DA | Dominion Atlantic Ry. Co. | CDN | TRAFFIC | |
| 68 | DAA | Decatur Aviation | ICAO1 | ||
| 69 | DAAC | DALLAS WOOD TRUCKING | SCAC4 | ||
| 70 | DAAD | DANISHA SCULPTURE | SCAC4 | ||
| 71 | DAAE | DELMAS AMERICA AFRICA EUROPEAN LINE | SCAC1 | ||
| 72 | DAAE | DELMAS AMERICA AFRICA EUROPEAN LINE | SCAC4 | ||
| 73 | DAAG | DANGO EXPRESS INC | SCAC4 | ||
| 74 | DAAG | Deutsche Lastautomobilfabrik AG | D | TRAFFIC | |
| 75 | DAAH | DAUGHERTY, SCOTT TRUCKING | SCAC4 | ||
| 76 | DAAI | DIVERSIFIED AGRICULTURAL AND INDUST | SCAC4 | ||
| 77 | DAAM | D & A AUTO TRANSPORTATION LLC | SCAC4 | ||
| 78 | DAAS | DOUBLE AA TRANSPORTATION | SCAC4 | ||
| 79 | DAAU | DANISH ARMY MATERIEL COMMAND | SCAC4 | ||
| 80 | DAB | Dassault Aviation | ICAO1 | ||
| 81 | DAB | Dansk Automobil Byggeri A/S | DK | TRAFFIC | |
| 82 | DABB | DANASONS BORDER SERVICES INC | SCAC4 | ||
| 83 | DABE | DREISBACH FREIGHT SERVICE (DIVISION | SCAC4 | ||
| 84 | DABI | DRIVE TRANSPORT INC | SCAC4 | ||
| 85 | DABL | D A B LOGISTICS INC | SCAC4 | ||
| 86 | DABM | DAMASKOI | SCAC4 | ||
| 87 | DABN | DIABLO TRUCKING INC | SCAC4 | ||
| 88 | DABO | DEANGELO BROTHERS INC | SCAC4 | ||
| 89 | DABR | D A TRANSPORT INC | SCAC4 | ||
| 90 | DABT | DIMAX EXPRESS INC | SCAC4 | ||
| 91 | DABX | Dingfelder & Balish, Inc. (DABX 100-119) (Merchants Despatch, Inc.) | 7/1935 | NAKINA | |
| 92 | DABX | Dingfelder & Balish, Inc. (DABX 6600-6619) | 7/1935 | NAKINA | |
| 93 | DAC | McDonnell Douglas | ICAO1 | ||
| 94 | DACA | DACSA TRUCKING LLC | SCAC4 | ||
| 95 | DACB | DOUBLE ACE CARGO INC | SCAC4 | ||
| 96 | DACC | DACCO INCORPORATED | SCAC4 | ||
| 97 | DACD | DAC | SCAC4 | ||
| 98 | DACF | DAYTON CONTAINERIZED FREIGHT INC | SCAC4 | ||
| 99 | DACI | DORMANS AUTO CENTER INC | SCAC4 | ||
| 100 | DACIA | AUTOMOBILE DACIA SA | RO | VKM |