- $1 million:
- 1911: 177
- 1912: 171
- 1913: 176
- 1914: 176
- 1915:
- 1916-06: 181
- 1916-12: 183
- 1917: 185
- 1918: 189
- 1919: 191
- 1920: 186
- 1921: 182
- 1922: 180
- 1923: 180
- 1924: 177
- 1925: 176
- 1926:
- 1927:
- 1928: 171
- 1929:
- 1930: 158
- 1931: 155
- 1932:
- 1933:
- 1934:
- 1935:
- 1951: 127
- 1955: 126
- $3 million:
- 1956: 113
- 1964: 98
- $5 million:
- 1965: 76
- 1975: 74
- $10 million:
- 1976: 58
- 1977: 59
- $50 million:
- $250 million:
- 1992:
- 1993:
- 1994:
- 1995:
- 1996: 10 BNSF Railway, Conrail, CSX, Grand Trunk Western, Illinois Central, Kansas City Southern, Norfolk Southern, Soo, Southern Pacific, Union Pacific
- 1997: 9 BNSF Railway, Conrail, CSX, Grand Trunk Western, Illinois Central, Kansas City Southern, Norfolk Southern, Soo, Union Pacific
- 1998: 9 BNSF Railway, Conrail, CSX, Grand Trunk Western, Illinois Central, Kansas City Southern, Norfolk Southern, Soo, Union Pacific
- 1999: 9 BNSF Railway, Conrail, CSX, Grand Trunk Western, Illinois Central, Kansas City Southern, Norfolk Southern, Soo Line, Union Pacific
- 2000: 8 BNSF Railway, CSX, Grand Trunk Western, Illinois Central, Kansas City Southern, Norfolk Southern, Soo Line, Union Pacific
- 2001: 8 BNSF Railway, Canadian National - Grand Trunk Western, Canadian National - Illinois Central, CSXT, Kansas City Southern, Norfolk Southern, Soo Line, Union Pacific
- 2002: 7 BNSF Railway, Canadian National - Grand Trunk Western, CSXT, Kansas City Southern, Norfolk Southern, Soo Line, Union Pacific
- 2003: 7 BNSF Railway, Canadian National - Grand Trunk Western, CSXT, Kansas City Southern, Norfolk Southern, Soo Line, Union Pacific
- 2004: 7 BNSF Railway, Canadian National - Grand Trunk Corporation, CSXT, Kansas City Southern, Norfolk Southern, Soo Line, Union Pacific
- 2005: 7 BNSF Railway Company Leased Lines and Wholly-Owned Subsidiaries; CSX Transportation, Inc.; Grand Trunk Corporation; The Kansas City Southern Railway Company; Norfolk Southern Combined Railroad Subsidiaries; Soo Line Railroad Company; Union Pacific Railroad Company
http://books.google.com/books?id=RdnZiHvabiMC&pg=PA112 (1918): lists on p. 36 (partial; also shows the New England Steamship Company as Class I), p. 112 (full), p. 151 (relinquished)
http://books.google.com/books?id=TKcTAAAAIAAJ&pg=PA1181 (1919): list on p. 1181 of railroads that were bumped up in 1919
http://books.google.com/books?id=QxYeAAAAMAAJ&pg=PA231 (1920): list on p. 231 (full, but also includes some "large terminal companies")
http://books.google.com/books?id=4kY3AAAAIAAJ&pgis=1 (1920 AAR): couldn't get a full list, but some information was used
http://www.nber.org/chapters/c4765.pdf : full lists on p. 52 (1928), p. 55 (1936), p. 58 (1940) - groupings are from this, and the group name is not listed separately in 1918 and 1920
http://books.google.com/books?id=hT5oAAAAIAAJ&pgis=1 (1951; includes history)
http://books.google.com/books?id=RSZPAAAAMAAJ&pgis=1 (1956; includes history)
http://cba.unomaha.edu/faculty/mohara/web/Koeppe_Competitive_RR_97.pdf : full list from 1970-1996 on p. 73
- Atlanta and St. Andrews Bay Railway became Class I in 1947 (1956 list)
- Bangor and Aroostook Railroad
- Bessemer and Lake Erie Railroad
- BNSF Railway ← Burlington Northern and Santa Fe Railway 1996 ← Burlington Northern Railroad formed in 1970
- Atchison, Topeka and Santa Fe Railway merged in 1995 (and affiliated companies, starting in 1936)
- ← Kansas City, Mexico and Orient Railroad leased in 1932
- ← Gulf, Colorado and Santa Fe Railway (not listed as Class I in 1920) (presumably an affiliated company) why isn't this listed in 1951 or 1956?
- ← Fort Worth and Rio Grande Railway became Class I in 1919; leased in 1937
- ← Panhandle and Santa Fe Railway (listed under AT&SF in 1920) (presumably an affiliated company) why isn't this listed in 1951 or 1956?
- ← Kansas City, Mexico and Orient Railway of Texas leased in 1931 (listed under KCM&O in 1918 and 1920)
- x Toledo, Peoria and Western Railway dropped by 1978 increase
- ← Chicago, Burlington and Quincy Railroad merged in 1970
- ← Colorado and Southern Railway merged in 1981
- ← Wichita Valley Railroad became Class I in 1919; leased in 1940? (listed under C&S in 1920) (not listed in 1936 - why? was it actually leased earlier?) (listed as Class II in 1951 and 1956, but doesn't seem to have been leased to anything)
- ← Fort Worth and Denver City Railway merged in 1982
- ← Great Northern Railway merged in 1970
- ← Northern Pacific Railway merged in 1970
- ← St. Louis-San Francisco Railway merged in 1980
- ← St. Louis, San Francisco and Texas Railway merged in 1964
- ← Spokane, Portland and Seattle Railway merged in 1970 (and affiliated companies, starting in 1936 - apparently these were Oregon Trunk Railway and Oregon Electric Railway, but were they Class I? the latter was, at least from 1971 to 1975)
- Atchison, Topeka and Santa Fe Railway merged in 1995 (and affiliated companies, starting in 1936)
- Boston and Maine Railroad dropped by 1992 increase
- Grand Trunk Corporation ← Grand Trunk Western Railway (including Muskegon Railway and Navigation Company, starting in 1936)
- x Canadian National Lines in New England dropped by 1955 increase ← Atlantic and St. Lawrence Railroad (listed under GT in 1920)
- x Central Vermont Railway dropped by 1978 increase
- ← Chicago, Detroit and Canada Grand Trunk Junction Railroad merged in 1928 (not listed in 1920)
- ← Detroit, Grand Haven and Milwaukee Railway merged in 1928 (not listed in 1920)
- ← Detroit, Toledo and Ironton Railroad merged in 1983
- x Detroit and Toledo Shore Line Railroad dropped by 1978 increase
- x Duluth, Winnipeg and Pacific Railway (relinquished) (including Duluth, Rainy Lake and Winnipeg Railway, starting in 1936) (last listed in 1979 - why?)
- Soo Line Railroad 1960 ← Minneapolis, St. Paul and Sault Ste. Marie Railway
- Canadian Pacific Lines in Maine ← International Railway of Maine ← Canadian Pacific Lines in Maine (relinquished)
- x Canadian Pacific Lines in Vermont dropped by 1955 increase (not listed in 1918 or 1920) - this is the Newport and Richford Railroad and former B&M from Newport to Wells River
- ← Chicago, Milwaukee, St. Paul and Pacific Railroad 1927; merged in 1985 ← Chicago, Milwaukee and St. Paul Railway
- ← Chicago, Terre Haute and Southeastern Railway leased in 1921
- Duluth, South Shore and Atlantic Railway
- x Minneapolis, Northfield and Southern Railway became Class I in 1956 [6] (last listed in 1982 - why?)
- Wisconsin Central Railway (new in 1956)
- Chicago and Illinois Midland Railway (not listed in 1918 or 1920; Class II in 1920 AAR)
- Chicago Great Western Railroad
- Chicago, Rock Island and Pacific Railway
- ← Chicago, Rock Island and Gulf Railway leased in 1939 (listed under CRI&P in 1918 and 1920)
- Colorado and Wyoming Railway became Class I in 1919 (relinquished) (not listed in 1928) - back up to Class I in 1941[7]
- Conrail 1976; broken up in 1999
- ← Ann Arbor Railroad merged in 1976
- ← Central Railroad of New Jersey merged in 1976
- ← Central Railroad of Pennsylvania split off in 1946; merged or leased in 1952
- ← Erie Lackawanna Railway 1968; merged in 1976 ← Erie-Lackawanna Railroad 1960
- ← Delaware, Lackawanna and Western Railroad merged in 1960
- ← Erie Railroad merged in 1960 (including Chicago and Erie Railroad, starting in 1936)
- ← Chicago and Erie Railroad leased by 1936?? (listed under Erie in 1920)
- x Lehigh and Hudson River Railway merged in 1976 (not listed by 1970)
- ← Lehigh Valley Railroad merged in 1976
- ← Penn Central Transportation 1968; merged in 1976
- ← New York Central Railroad merged in 1968 (including Boston and Albany Railroad, 1918 only - not listed in 1920 or 1928)
- ← Cleveland, Cincinnati, Chicago and St. Louis Railway leased in 1930
- ← Cincinnati Northern Railroad leased ca. 1929
- ← Evansville, Indianapolis and Terre Haute Railway leased ca. 1929 (not listed in 1918 or 1920)
- ← Michigan Central Railroad leased in 1930
- ← Toledo and Ohio Central Railway leased in 1922 (listed under NYC in 1920)
- ← Kanawha and Michigan Railway leased in 1922 (listed under NYC in 1920)
- ← Ulster and Delaware Railroad merged in 1932
- ← Cleveland, Cincinnati, Chicago and St. Louis Railway leased in 1930
- New York, New Haven and Hartford Railroad merged in 1969
- ← Central New England Railway merged in 1927
- ← Pennsylvania Railroad, lines east merged in 1968
- ← Cincinnati, Lebanon and Northern Railway became Class I in 1919; leased in 1921 (not listed in 1918; listed under Pennsy lines west in 1920)
- ← Cumberland Valley Railroad merged in 1919 (listed under Pennsy in 1920)
- ← Grand Rapids and Indiana Railway leased in 1921
- ← New York, Philadelphia and Norfolk Railroad leased in 1920 (listed under Pennsy in 1920)
- ← Pennsylvania Company, lines west leased in 1918
- ← Pittsburgh, Cincinnati, Chicago and St. Louis Railroad leased in 1921
- ← New York Central Railroad merged in 1968 (including Boston and Albany Railroad, 1918 only - not listed in 1920 or 1928)
- ← Pennsylvania-Reading Seashore Lines 1933; merged in 1976 ← Atlantic City Railroad (listed under Reading in 1920 and 1928)
- ← West Jersey and Seashore Railroad leased in 1933 (listed under PRR in 1928; leased to PRR in 1930)
- ← Reading Company 1923; merged in 1976 ← Philadelphia and Reading Railway
- ← Perkiomen Railroad became Class I in 1919; leased in 1929 (listed as Class II in 1918; listed under Reading in 1920)
- ← Port Reading Railroad leased in 1929 (listed under Reading in 1920)
- CSX Transportation 1986
- ← Baltimore and Ohio Railroad merged in 1986 (including Coal and Coke Railway, 1918 and 1920)
- ← Buffalo and Susquehanna Railroad leased in 1932
- ← Buffalo, Rochester and Pittsburgh Railway leased in 1932
- ← Cincinnati, Indianapolis and Western Railroad leased in 1927
- ← Western Maryland Railway leased in 1983
- ← Chesapeake and Ohio Railway merged in 1986
- ← Hocking Valley Railway merged in 1930
- ← Pere Marquette Railway merged in 1947
- x Richmond, Fredericksburg and Potomac Railroad dropped by 1978 increase; merged in 1991?
- ← Washington Southern Railway merged in 1920
- ← Seaboard System Railroad 1983; merged in 1986
- x Atlanta and West Point Railroad merged in 1983 (but last listed in 1974?)
- ← Carolina, Clinchfield and Ohio Railway leased in 1983?
- x Georgia Railroad Lessee Organization dropped by 1978 increase; merged in 1983
- ← Seaboard Coast Line Railroad 1967; merged in 1983
- ← Atlantic Coast Line Railroad merged in 1967
- ← Atlanta, Birmingham and Coast Railroad 1926; merged in 1946 ← Atlanta, Birmingham and Atlantic Railway
- ← Charleston and Western Carolina Railway merged in 1959
- ← Louisville and Nashville Railroad merged in 1983
- ← Louisville, Henderson and St. Louis Railway leased in 1928
- ← Monon Railroad 1956; merged in 1971 ← Chicago, Indianapolis and Louisville Railway
- ← Nashville, Chattanooga and St. Louis Railway merged in 1957
- ← Seaboard Air Line Railway merged in 1967
- ← Atlantic Coast Line Railroad merged in 1967
- x Western Railway of Alabama merged in 1983 (but last listed in 1974?)
- ← Baltimore and Ohio Railroad merged in 1986 (including Coal and Coke Railway, 1918 and 1920)
- Delaware and Hudson Company (last listed in 1988 - why?)
- Duluth, Missabe and Iron Range Railway 1937 ← Duluth, Missabe and Northern Railway
- ← Duluth and Iron Range Railroad leased in 1930
- Elgin, Joliet and Eastern Railway became Class II in 1986[8] "NOTE: in 1986 there were 18 Class I railroads reporting to the ICC as opposed to 24 in 1985. The reduction in number of reporting Class I's is due to the reclassification of EJ&E to a Class II railroad and the consolidation of Class I reporting under a single corporate entity for the following railroads: CSX Transportation: Baltimore & Ohio Railroad, Chesapeake & Ohio Railway and Seaboard System Railroad, Inc. / Norfolk Southern Corp: Southern System and Norfolk & Western Railroad / Union Pacific Railroad: Union Pacific Railroad, Western Pacific Railroad and Missouri Pacific Railroad"
- Florida East Coast Railway
- Georgia and Florida Railroad became Class I in 1919 (not listed as Class I in 1918 or 1920) (including Statesboro Northern Railway, starting in 1936)
- Green Bay and Western Railroad became Class I in 1919 (not listed in 1918; listed as Class I in 1920 and 1920 AAR)
- Illinois Central Railroad 1988 ← Illinois Central Gulf Railroad 1972 ← Illinois Central Railroad
- ← Alabama and Vicksburg Railway leased in 1926
- ← Gulf, Mobile and Ohio Railroad 1940; merged in 1972
- ← Alton Railroad 1931; merged in 1947 ← Chicago and Alton Railroad
- ← Gulf, Mobile and Northern Railroad merged in 1940
- ← New Orleans Great Northern Railroad leased in 1933
- ← Mobile and Ohio Railroad merged in 1940
- ← Gulf and Ship Island Railroad merged in 1945
- ← Vicksburg, Shreveport and Pacific Railway leased in 1925
- ← Yazoo and Mississippi Valley Railroad merged in 1946
- Kansas City Southern Railway
- ← Texarkana and Fort Smith Railway leased in 1934 (listed under KCS in 1918)
- Louisiana and Arkansas Railway (including Louisiana, Arkansas and Texas Railway, starting in 1940)
- ← Louisiana Railway and Navigation Company leased in 1929 (not listed in 1918 or 1920)
- ← Louisiana, Arkansas and Texas Railway 1930; merged in 1939 ← Louisiana Railway and Navigation Company of Texas (not listed in 1918 or 1920)
- Kansas, Oklahoma and Gulf Railway 1919-1921 ← Missouri, Oklahoma and Gulf Railway (not listed in 1918)
- Lakefront Dock and Railroad Terminal???
- Lake Superior and Ishpeming Railroad (listed as Class II in 1918 and 1920)
- Lehigh and New England Railroad
- Litchfield and Madison Railway became Class I in 1956
- Long Island Rail Road
- Maine Central Railroad (last listed in 1978 - why?)
- Minneapolis and St. Louis Railroad
- Monongahela Railway
- New York Connecting Railroad (not listed as Class I in 1918 or 1920)
- New York, Chicago and St. Louis Railroad
- ← Lake Erie and Western Railroad merged in 1923
- ← Toledo, St. Louis and Western Railroad merged in 1923 (not listed in 1920)
- ← Wheeling and Lake Erie Railway leased in 1949
- New York, Ontario and Western Railway
- New York, Susquehanna and Western Railroad (including Wilkes-Barre and Eastern Railroad, starting in 1936; not listed in 1940, but listed in 1951 and 1956)
- Norfolk Southern Railway 1982
- ← Norfolk and Western Railway merged in 1982
- x Akron, Canton and Youngstown Railway (not listed in 1918 or 1920) (last listed in 1974 - why?)
- x Illinois Terminal Company dropped by 1978 increase (not listed in 1918 or 1920)
- ← Southern Railway merged in 1982
- x Alabama Great Southern Railroad (last listed in 1984 - why?)
- Carolina and Northwestern Railway became Class I in 1956
- x Central of Georgia Railway (last listed in 1984 - why?)
- Savannah and Atlanta Railway became Class I in 1956
- x Cincinnati, New Orleans and Texas Pacific Railway (last listed in 1984 - why?)
- x Georgia Southern and Florida Railway dropped by 1978 increase
- New Orleans and Northeastern Railroad
- x Norfolk Southern Railroad dropped by 1978 increase
- ← Northern Alabama Railway became Class I in 1919; merged in 1939 (listed as Class II in 1918 and 1920; listed as Class I in 1920 AAR)
- ← Norfolk and Western Railway merged in 1982
- Piedmont and Northern Railway became Class I in 1956
- Pittsburgh and Lake Erie Railroad became Class II in 1985[9]
- Pittsburgh and West Virginia Railway became Class I in 1919
- Rutland Railway ← Rutland Railroad became Class II in 1963[10]
- San Diego and Arizona Eastern Railway became Class I in 1963 [11]
- Staten Island Rapid Transit Railway (listed under B&O in 1920)
- Tennessee Central Railroad
- Texas Mexican Railway (new in 1936)
- Union Pacific Railroad
- ← Chicago and North Western Railway merged in 1995
- ← Los Angeles and Salt Lake Railroad leased in 1936
- ← Missouri Pacific Railroad leased in 1982?
- ← Beaumont, Sour Lake and Western Railway became Class I in 1919; merged in 1956 (listed under Gulf Coast Lines in 1920)
- ← Chicago and Eastern Illinois Railroad merged in 1976
- ← International and Great Northern Railway merged in 1956
- x Missouri-Illinois Railroad (new in 1936) dropped by 1978 increase [12]
- ← Missouri, Kansas and Texas Railway merged in 1988 (and controlled companies, starting in 1936)
- ← Missouri, Kansas and Texas Railway of Texas merged in 1960 (presumably a controlled company) why isn't this listed in 1951 or 1956?
- ← Wichita Falls and Northwestern Railway leased in 1923
- ← Missouri, Kansas and Texas Railway of Texas merged in 1960 (presumably a controlled company) why isn't this listed in 1951 or 1956?
- ← New Orleans, Texas and Mexico Railway merged in 1956 (listed under Gulf Coast Lines in 1920)
- ← St. Louis, Brownsville and Mexico Railway merged in 1956 (listed under Gulf Coast Lines in 1920)
- ← San Antonio, Uvalde and Gulf Railroad merged in 1956 (listed as Class II in 1918 and 1920)
- ← Texas and Pacific Railway merged in 1976
- ← Oregon Short Line Railroad leased in 1936 (listed under UP in 1920)
- ← Oregon-Washington Railroad and Navigation Company leased in 1936 (listed under UP in 1920)
- ← St. Joseph and Grand Island Railway leased in 1936
- ← Southern Pacific Company merged in 1996
- ← Arizona Eastern Railroad leased in 1924 (listed under SP in 1920)
- ← Denver and Rio Grande Railroad merged in 1988?
- ← Denver and Salt Lake Railroad merged in 1947
- ← El Paso and Southwestern Railroad leased in 1924
- ← Arizona and New Mexico Railway leased in 1922 (relinquished)
- x Northwestern Pacific Railroad dropped by 1978 increase
- x St. Louis Southwestern Railway dropped by 1992 increase (and affiliated companies, starting in 1936)
- ← St. Louis Southwestern Railway of Texas leased in 1954 (presumably an affiliated company) why isn't this listed in 1951?
- Texas and New Orleans Railroad (listed under SP in 1920)
- ← Galveston, Harrisburg and San Antonio Railway leased in 1927 (listed under SP in 1920)
- ← San Antonio and Aransas Pass Railway leased in 1925
- ← Houston and Texas Central Railroad leased in 1927 (listed under SP in 1920)
- ← Houston, East and West Texas Railway leased in 1927 (listed under SP in 1920)
- ← Louisiana Western Railroad leased in 1926 (listed under SP in 1920)
- ← Morgan's Louisiana and Texas Railroad and Steamship Company leased in 1926 (listed under SP in 1920)
- ← Galveston, Harrisburg and San Antonio Railway leased in 1927 (listed under SP in 1920)
- x Spokane International Railway (relinquished) (last listed in 1974 - why?)
- ← Western Pacific Railroad leased in 1982?
- Sacramento Northern Railway (new in 1956)
- Virginian Railway
- Wabash Railway
- Alabama, Tennessee and Northern Railroad became Class II 1963-01-01[13]
- Atlantic and Danville Railway dropped by 1955 increase (new in 1951)
- Baltimore, Chesapeake and Atlantic Railway (not listed in 1918 or 1936; listed as Class I in 1920, 1920 AAR, and 1928)
- Bingham and Garfield Railway (relinquished) (not listed in 1936)
- Burlington-Rock Island Railroad 1930; leased by FtW&D and CRI&P in 1950 ← Trinity and Brazos Valley Railway (not listed as Class I in 1918 or 1920)
- Cambria and Indiana Railroad dropped by 1955 increase (new in 1936)
- Chicago, Peoria and St. Louis Railroad (not listed in 1928)
- Colorado Midland Railroad (relinquished) (not listed in 1928)
- Columbus and Greenville Railway 1920; dropped by 1955 increase ← Southern Railway in Mississippi
- Copper River and Northwestern Railway (not listed in 1918 or 1920; not listed in 1940)
- Cripple Creek and Colorado Springs Railroad (relinquished) (not listed in 1928)
- Detroit and Mackinac Railway dropped by 1955 increase
- Fonda, Johnstown and Gloversville Railroad became Class I in 1919 (not listed anywhere else)
- Fort Smith and Western Railroad became Class I in 1919 (not listed in 1918 or 1920; not listed in 1940)
- Hudson and Manhattan Railroad (not listed as Class I in 1920 or 1928; only listed as Class I in 1918)
- Lewiston and Auburn Railroad (not listed in 1918 or 1928; listed under GT in 1920) - apparently leased to A&StL in 1874
- Maryland, Delaware and Virginia Railway became Class I in 1919 (listed as Class II in 1918; listed as Class I in 1920 and 1920 AAR; not listed in 1928)
- Midland Valley Railroad dropped by 1955 increase
- Mineral Range Railroad became Class I in 1919 (not listed in 1928) - was this leased by the DSS&A?
- Minnesota and International Railway became Class I in 1919 (not listed as Class I in 1920 or 1928)
- Mississippi Central Railroad became Class I in 1919; dropped by 1955 increase (listed as Class II in 1918; listed as Class I in 1920 and 1920 AAR)
- Missouri and Arkansas Railway 1935 (not listed in 1951 or 1956) ← Missouri and North Arkansas Railroad
- Montour Railroad (not listed in 1918 or 1920) (listed in 1951; not listed in 1956)
- Nevada Northern Railway (relinquished) (not listed in 1951 or 1956)
- New Jersey and New York Railroad became Class I in 1919 (listed as Class II in 1918 and 1920; not listed in 1940 - was it leased to the Erie?)
- Oahu Railway and Land Company (not listed in 1918 or 1920; not listed in 1940)
- Oklahoma City-Ada-Atoka Railway dropped by 1955 increase (new in 1936)
- Oregon Electric Railway (listed from 1971 to 1975) - not sure why it was added or dropped
- Pacific Electric Railway [14]
- Pittsburg and Shawmut Railroad dropped by 1955 increase
- Pittsburg, Shawmut and Northern Railroad abandoned in 1947 (relinquished)
- Quanah, Acme and Pacific Railway [15]
- Quincy, Omaha and Kansas City Railroad became Class I in 1919 (listed as Class II in 1918; listed under CB&Q in 1920 and 1928; not listed in 1936)
- San Diego and Arizona Railway (not listed in 1918 or 1920; not listed in 1936)
- Texas and Northern Railway began common carrier operations in 1948; dropped by 1955 increase
- Utah Railway dropped by 1955 increase (not listed in 1918 or 1920; listed as Class I in 1920 AAR)
- Wichita Falls and Southern Railroad (not listed in 1918 or 1920; not listed in 1940)