| Railroad | Records | Links |
|---|
| Totals | 33,505 | 1,022 |
|---|
| Dakota Pacific Railroad | 5 | |
| Dallas Consolidated Electric Street Railway | 204 | |
| Danbury and Norwalk Railroad | 31 | 1 |
| Dansville and Mount Morris Railroad | 10 | 2 |
| Danville and Western Railway | 7 | 1 |
| Danville Olney and Ohio River Railroad | 5 | |
| Dardanelle and Russellville Railway | 5 | |
| Darien and Western Railroad | 7 | |
| Dauphin and Susquehanna Railroad | 11 | 1 |
| Davenport and St Paul Railroad | 6 | |
| Davenport, Rock Island and Northwestern Railway | 7 | |
| Dayton and Cincinnati Short Line Railroad | 6 | |
| Dayton and Michigan Railroad | 25 | 1 |
| Dayton and Union Railroad | 24 | |
| Dayton and Western Railroad | 31 | |
| Dayton, Lebanon and Cincinnati Railroad | 7 | |
| Dayton, Xenia and Belpre Railroad | 20 | |
| Deadwood Central Railroad | 4 | |
| Delaware and Hudson Railway | 73 | 2 |
| Delaware Railroad | 24 | 1 |
| Delaware River Railroad | 5 | |
| Delaware Valley Railroad | 7 | |
| Delaware, Lackawanna and Western Railroad | 114 | 5 |
| Delaware, Susquehanna and Schuylkill Railroad | 10 | |
| Denison, Bonham and New Orleans Railroad | 4 | |
| Denver and Rio Grande Railroad | 1138 | 3 |
| Denver and Rio Grande Western Railway | 40 | 3 |
| Denver and Southwestern Railway | 1 | |
| Denver Utah and Pacific Railroad | 4 | |
| Denver, Lakewood and Golden Railroad | 32 | |
| Denver, South Park and Pacific Railway | 5 | |
| Des Moines and Kansas City Railway | 4 | |
| Des Moines Navigation and Railroad Company | 11 | 1 |
| Des Moines Northern and Western Railway | 7 | |
| Des Moines Union Railway | 10 | |
| Des Moines Valley Railroad | 22 | |
| Des Moines, Iowa Falls and Northern Railroad | 5 | |
| Detroit and Bay City Railroad | 6 | 1 |
| Detroit and Charlevoix Railroad | 5 | |
| Detroit and Mackinac Railway | 12 | |
| Detroit and Milwaukee Railroad | 32 | 2 |
| Detroit and Toledo Railroad | 11 | 1 |
| Detroit Monroe Toledo Railroad | | 1 |
| Detroit Southern Railroad | 14 | |
| Detroit Union Railroad Depot and Station Company | 4 | |
| Detroit, Bay City and Alpena Railroad | 4 | |
| Detroit, Grand Haven and Milwaukee Railway | 11 | 1 |
| Detroit, Lansing and Northern Railroad | 17 | 2 |
| Dominion Atlantic Railway | 9 | |
| Dothan, Hartford and Florida Railroad | 5 | |
| Dover and Winnipiseogee Railroad | 24 | |
| Drummond and Southwestern Railway | 3 | |
| Dry Fork Railroad | 9 | |
| Dubuque and Sioux City Railroad | 20 | |
| Dubuque Southwestern Railroad | 11 | |
| Duluth and Iron Range Railroad | 23 | 2 |
| Duluth and Northeastern Railroad | 5 | |
| Duluth and Northern Minnesota Railroad | 5 | |
| Duluth, Missabe and Northern Railway | 18 | 1 |
| Duluth, South Shore and Atlantic Railway | 36 | 2 |
| Duluth, Virginia and Rainy Lake Railway | 6 | |
| Dunbar and Wansaukee Railway | 5 | |
| Dunkirk, Allegheny Valley and Pittsburgh Railroad | 10 | 1 |
| Durham and Charlotte Railroad | 7 | |
| Dutchess and Columbia Railroad | 5 | |
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