1922 edit
- Atchison, Topeka and Santa Fe Railroad
- Baltimore and Ohio Railroad
- Canadian Government Railways
- Canadian Northern Railway
- Canadian Pacific Railway
- Central Railroad of New Jersey
- Chesapeake and Ohio Railroad
- Chicago and Alton Railroad
- Chicago, Burlington and Quincy Railway
- Chicago Great Western Railroad
- Chicago, Milwaukee and St. Paul Railway
- Chicago and North Western Transportation Company
- Chicago, Rock Island and Pacific Railway
- Colorado and Southern Railway
- Delaware, Lackawanna and Western Railroad
- Denver and Rio Grande Railroad/Western Pacific Railroad
- Erie Railroad
- Grand Trunk Railway
- Great Northern Railway
- Illinois Central Railroad
- Louisville and Nashville Railroad
- Missouri-Pacific Railroad
- New York Central Railroad
- New York, New Haven and Hartford Railroad
- Norfolk and Western Railroad
- Northern Pacific Railroad
- Pennsylvania Railroad
- Salt Lake Route
- Seaboard Air Line Railroad
- Southern Railroad
- Southern Pacific Railroad
- Union Pacific Railroad
- Wabash Railway
1890 edit
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- Atlantic and Pacific Railroad
- Burlington and Missouri River Railroad
- Carson and Colorado Railroad
- Chicago and Rock Island Railroad
- Colorado Midland Railroad
- Dallas and Greenville Railroad
- Denver, Texas and Fort Worth Railroad
- Fort Worth and Denver Railway
- Fort Worth and Rio Grande Railroad
- Fremont, Elkhorn and Missouri Valley Railroad
- Great Northern Railway
- Gulf, Colorado, and Santa Fe Railroad
- Houston East and West Texas Railroad
- Houston and Texas Central Railroad
- International and Great Northern Railroad
- Marshall, Paris and Northwestern Railroad
- Mexican National Railroad
- Missouri-Kansas-Texas Railroad
- Missouri Pacific Railroad
- Northern Pacific Railroad
- Rio Grande Western Railroad
- St. Louis, Arkansas and Texas Railroad
- St. Louis and San Francisco Railroad
- San Antonio and Aransas Pass Railroad
- Seattle, Lake Shore and Eastern Railway
- Southern Pacific Railroad
- Texas Central Railroad
- Texas and Pacific Railway
- Union Pacific Railroad
- Utah Central Railway
1906 edit
- Morgan Group (J. P. Morgan): Atlantic Coast Line Railroad (including Louisville and Nashville Railroad), Southern Railway, Erie Railroad, Lehigh Valley Railroad
- Hill-Morgan Group (James J. Hill, J. P. Morgan): Great Northern Railway, Northern Pacific Railway, Chicago, Burlington and Quincy Railroad
- Harriman Group (E. H. Harriman): Union Pacific Railroad, Southern Pacific Railroad, Illinois Central Railroad ("also identified with" Erie Railroad and "strongly identified with" New York Central Railroad)
- Pennsylvania Group: Pennsylvania Railroad, Chesapeake and Ohio Railway, Norfolk and Western Railway
- New York Central Group: New York Central and Hudson River Railroad, Lake Shore and Michigan Southern Railway, Michigan Central Railroad, Cleveland, Cincinnati, Chicago and St. Louis Railway, New York, Chicago and St. Louis Railroad, Pittsburgh and Lake Erie Railroad, others ("also had heavy holdings in" Philadelphia and Reading Railway)
- Harriman-Pennsylvania-New York Central Joint Group: Baltimore and Ohio Railroad, Philadelphia and Reading Railway (including Central Railroad of New Jersey)
- Gould Group (George Jay Gould I): Missouri Pacific Railway, Denver and Rio Grande Railroad, Wabash Railroad, Texas and Pacific Railway, St. Louis Southwestern Railway, Western Maryland Railroad, Wheeling and Lake Erie Railroad, others
- Rock Island Group: Chicago, Rock Island and Pacific Railway, St. Louis and San Francisco Railroad, Chicago and Eastern Illinois Railroad, Evansville and Terre Haute Railroad
- Others
- Harriman and Morgan: Atchison, Topeka and Santa Fe Railway
- Harriman and William Rockefeller: Chicago, Milwaukee and St. Paul Railway
- Vanderbilt (which one?): Chicago and North Western Railway
- Delaware and Hudson Company
- Delaware, Lackawanna and Western Railroad
- Morgan, Rockefeller, and Pennsylvania: New York, New Haven and Hartford Railroad
- "general joint interests": Hocking Valley Railway