| Name | Mark | System [nb 1] | From | To | Successor | Notes |
|---|
| Albia and Centerville Railway | | MSTL | 1890 | 1910 | Southern Iowa Traction Company |
| Albia, Knoxville and Des Moines Railroad | | CB&Q | 1868 | 1901 | Chicago, Burlington and Quincy Railroad |
| Ames and College Railway | | | 1890 | 1907 | Fort Dodge, Des Moines and Southern Railroad |
|
| Atchison, Topeka and Santa Fe Railroad | | ATSF | 1889 | 1895 | Atchison, Topeka and Santa Fe Railway |
| Atchison, Topeka and Santa Fe Railway | ATSF | ATSF | 1895 | 1996 | Burlington Northern and Santa Fe Railway |
| Atlantic and Audubon Railroad | | RI | 1878 | 1880 | Chicago, Rock Island and Pacific Railway |
| Atlantic Northern Railway | | | 1913 | 1936 | N/A |
| Atlantic Northern and Southern Railway | | | 1906 | 1913 | Atlantic Northern Railway, Atlantic Southern Railway |
| Atlantic Southern Railroad | | RI | 1879 | 1880 | Chicago, Rock Island and Pacific Railway |
| Atlantic Southern Railway | | | 1913 | 1915 | N/A |
| Avoca, Harlan and Northern Railroad | | RI | 1878 | 1899 | Chicago, Rock Island and Pacific Railway |
| Avoca, Macedonia and South Western Railroad | | RI | 1879 | 1880 | Chicago, Rock Island and Pacific Railway |
| Bellevue and Cascade Railroad | | | 1933 | 1936 | N/A |
| Boone County Railway | | CNW | 1899 | 1900 | Chicago and North Western Railway |
| Boone Valley Coal and Railway Company | | CNW | 1893 | 1899 | Marshalltown and Dakota Railway |
| Boyer Valley Railway | | CNW | 1898 | 1900 | Chicago and North Western Railway |
| Brownville and Nodaway Valley Railway | | CB&Q | 1872 | 1901 | Chicago, Burlington and Quincy Railroad |
| Burlington, Cedar Rapids and Minnesota Railway | | RI | 1868 | 1878 | Burlington, Cedar Rapids and Northern Railway |
| Burlington, Cedar Rapids and Northern Railway | | RI | 1876 | 1903 | Chicago, Rock Island and Pacific Railway |
| Burlington, Fort Madison and Southwestern Railway | | CB&Q | 1870 | 1871 | Burlington and Southwestern Railway |
| Burlington and Missouri Railroad | | CB&Q | 1871 | 1901 | Chicago, Burlington and Quincy Railroad |
| Burlington and Missouri River Railroad | | CB&Q | 1852 | 1875 | Chicago, Burlington and Quincy Railroad |
| Burlington and Missouri River Railroad in Nebraska | | CB&Q | 1869 | 1880 | Chicago, Burlington and Quincy Railroad |
| Burlington, Muscatine and Northwestern Railway | | RI | 1925 | 1952 | Chicago, Rock Island and Pacific Railroad |
| Burlington Northern Inc. | BN | | 1970 | 1981 | Burlington Northern Railroad |
| Burlington Northern Railroad | BN | | 1981 | 1996 | Burlington Northern and Santa Fe Railway |
| Burlington and Northwestern Railway | | CB&Q | 1876 | 1902 | Burlington and Western Railway |
| Burlington and Northwestern Narrow Gauge Railway | | CB&Q | 1875 | 1876 | Burlington and Northwestern Railway |
| Burlington and Southwestern Railway | | CB&Q | 1871 | 1880 | Chicago, Burlington and Kansas City Railway |
| Burlington and Southwestern Railway | | CB&Q | 1869 | 1870 | Burlington, Fort Madison and Southwestern Railway |
| Burlington and Western Railway | | CB&Q | 1881 | 1903 | Chicago, Burlington and Quincy Railroad |
| Cedar Falls and Minnesota Railroad | | IC | 1858 | 1896 | Dubuque and Sioux City Railroad |
| Cedar Falls and New Hartford Railroad | | IC | 1903 | 1904 | Dubuque and Sioux City Railroad |
| Cedar Falls and North Eastern Railroad | | IC | 1904 | 1905 | Dubuque and Sioux City Railroad |
| Cedar Rapids and Burlington Railroad | | RI | 1867 | 1868 | Burlington, Cedar Rapids and Minnesota Railway |
| Cedar Rapids and Chicago Railroad | | IC | 1886 | 1888 | Dubuque and Sioux City Railroad |
| Cedar Rapids and Clinton Railway | | RI | 1882 | 1902 | Burlington, Cedar Rapids and Northern Railway |
| Cedar Rapids, Garner and Northwestern Railway | | RI | 1898 | 1900 | Burlington, Cedar Rapids and Northern Railway |
| Cedar Rapids, Iowa Falls and Northwestern Railway | | RI | 1880 | 1902 | Burlington, Cedar Rapids and Northern Railway |
| Cedar Rapids and Missouri River Railroad | | CNW | 1860 | 1884 | Chicago and North Western Railway |
| Cedar Rapids and St. Louis Railroad | | MILW | 1871 | 1881 | Chicago, Milwaukee and St. Paul Railway |
| Cedar Rapids and St. Paul Railway | | RI | 1865 | 1868 | Burlington, Cedar Rapids and Minnesota Railway |
| Cedar Valley Railroad | CVAR | | 1984 | 1991 | Cedar River Railroad |
| Centerville, Albia and Southern Railway | | | 1914 | 1916 | Iowa Southern Utilities Company |
| Centerville, Moravia and Albia Railroad | | MSTL | 1879 | 1890 | Albia and Centerville Railway |
| Central Railroad of Iowa | | MSTL | 1869 | 1877 | Central Iowa Railway |
| Central Iowa Railway | CIRC | | 1974 | 1974 | N/A |
| Central Iowa Railway | | MSTL | 1878 | 1888 | Iowa Railway |
| Chariton, Des Moines and Southern Railroad | | CB&Q | 1876 | 1901 | Chicago, Burlington and Quincy Railroad |
| Charles City Railway Line, Inc. | CCRY | | 1987 | 1994 | N/A |
| Charles City Western Railway | | | 1910 | 1964 | Iowa Terminal Railroad |
| Cherokee and Dakota Railroad | | IC | 1887 | 1888 | Dubuque and Sioux City Railroad |
| Chicago, Anamosa and Northern Railway | | | 1903 | 1916 | N/A |
| Chicago, Bellevue, Cascade and Western Railway | | MILW | 1878 | 1880 | Chicago, Clinton, Dubuque and Minnesota Railroad |
| Chicago, Burlington and Kansas City Railway | | CB&Q | 1880 | 1901 | Chicago, Burlington and Quincy Railroad |
| Chicago, Burlington and Northern Railroad | | CB&Q | 1885 | 1899 | Chicago, Burlington and Quincy Railroad |
| Chicago, Burlington and Quincy Railroad | CB&Q | CB&Q | 1868 | 1970 | Burlington Northern Inc. |
| Chicago, Burlington and Quincy Railway | | CB&Q | 1901 | 1907 | N/A | Leased the Chicago, Burlington and Quincy Railroad |
| Chicago, Burlington and Pacific Railroad | | MSTL | 1882 | 1882 | Central Iowa Railway |
| Chicago, Clinton and Dubuque Railroad | | MILW | 1871 | 1877 | Clinton and Dubuque Railroad |
| Chicago, Clinton, Dubuque and Minnesota Railroad | | MILW | 1878 | 1880 | Chicago, Milwaukee and St. Paul Railway |
| Chicago, Clinton and Western Railroad | | RI | 1877 | 1878 | Burlington, Cedar Rapids and Northern Railway |
| Chicago, Decorah and Minnesota Railway | | RI | 1881 | 1902 | Burlington, Cedar Rapids and Northern Railway |
| Chicago, Dubuque and Minnesota Railroad | | MILW | 1871 | 1877 | Dubuque and Minnesota Railroad |
| Chicago, Fort Madison and Des Moines Railroad | | CB&Q | 1899 | 1901 | Chicago, Burlington and Quincy Railroad |
| Chicago, Fort Madison and Des Moines Railway | | CB&Q | 1890 | 1899 | Chicago, Fort Madison and Des Moines Railroad |
| Chicago Great Western Railroad | CGW | CGW | 1909 | 1941 | Chicago Great Western Railway |
| Chicago Great Western Railway | CGW | CGW | 1940 | 1968 | Chicago and North Western Railway |
| Chicago Great Western Railway | | CGW | 1892 | 1909 | Chicago Great Western Railroad |
| Chicago, Iowa and Dakota Railway | | CNW | 1882 | 1903 | Chicago and North Western Railway |
| Chicago, Iowa and Kansas Railway | | RI | 1876 | 1877 | Chicago, Clinton and Western Railroad |
| Chicago, Iowa and Minnesota Railway | | CNW | 1895 | 1901 | Chicago and North Western Railway |
| Chicago, Iowa and Nebraska Railroad | | CNW | 1856 | 1884 | Chicago and North Western Railway |
| Chicago, Iowa and Northern Pacific Railroad | | RI | 1885 | 1888 | Davenport, Iowa and Dakota Railroad |
| Chicago and Iowa Western Railway | | RI | 1891 | 1894 | Cedar Rapids, Iowa Falls and Northwestern Railway |
| Chicago, Milwaukee and St. Paul Railway | | MILW | 1874 | 1928 | Chicago, Milwaukee, St. Paul and Pacific Railroad |
| Chicago, Milwaukee, St. Paul and Pacific Railroad | MILW | MILW | 1928 | 1985 | The Milwaukee Road, Inc. |
| Chicago and North Western Railway | CNW | CNW | 1864 | 1972 | Chicago and North Western Transportation Company |
| Chicago and North Western Transportation Company | CNW | CNW | 1972 | 1995 | Union Pacific Railroad |
| Chicago, Omaha and St. Joseph Railroad | | RI | 1872 | 1882 | Cedar Rapids and Clinton Railway |
| Chicago, Rock Island and Pacific Railroad | RI, ROCK | RI | 1947 | 1980 | Burlington Northern Inc., Cedar Rapids and Iowa City Railway, Chicago, Milwaukee, St. Paul and Pacific Railroad, Chicago and North Western Railway, Iowa Railroad, Iowa Northern Railway, Keokuk Junction Railway, Kewash Railroad |
| Chicago, Rock Island and Pacific Railroad | | RI | 1902 | 1916 | Chicago, Rock Island and Pacific Railway |
| Chicago, Rock Island and Pacific Railroad | | RI | 1866 | 1880 | Chicago, Rock Island and Pacific Railway |
| Chicago, Rock Island and Pacific Railway | RI | RI | 1880 | 1948 | Chicago, Rock Island and Pacific Railroad |
| Chicago, St. Paul and Kansas City Railway | | CGW | 1886 | 1893 | Chicago Great Western Railway |
| Chicago, St. Paul, Minneapolis and Omaha Railway | CMO | CNW | 1881 | 1972 | Chicago and North Western Transportation Company |
| Chicago, Santa Fe and California Railway | | ATSF | 1887 | 1900 | Atchison, Topeka and Santa Fe Railway |
| Chicago, Santa Fe and California Railway of Iowa | | ATSF | 1886 | 1887 | Chicago, Santa Fe and California Railway |
| Chicago and South Western Railway | | RI | 1869 | 1876 | Iowa Southern and Missouri Northern Railroad |
| Chillicothe and Chariton Railroad | | CB&Q | 1878 | 1901 | Chicago, Burlington and Quincy Railroad |
| Clarinda, College Springs and South Western Railroad | | CB&Q | 1878 | 1901 | Chicago, Burlington and Quincy Railroad |
| Clinton and Dubuque Railroad | | MILW | 1877 | 1878 | Chicago, Clinton, Dubuque and Minnesota Railroad |
| Colfax Northern Railroad | | | 1901 | 1912 | Colfax Northern Railway |
| Colfax Northern Railway | | | 1912 | 1926 | N/A |
| Council Bluffs Railway | CBGR | | 1991 | 2006 | Iowa Interstate Railroad |
| Council Bluffs and Ottumwa Railway | CBOA | | 1989 | 1991 | Council Bluffs Railway |
| Council Bluffs and St. Joseph Railroad | | CB&Q | 1858 | 1869 | St. Joseph and Council Bluffs Railroad |
| Council Bluffs and St. Louis Railway | | WAB | 1878 | 1886 | Omaha and St. Louis Railway |
| Creston Branch of the Burlington and Missouri River Railroad | | CB&Q | 1871 | 1901 | Chicago, Burlington and Quincy Railroad |
| Creston and Northern Railroad | | CB&Q | 1878 | 1901 | Chicago, Burlington and Quincy Railroad |
| Creston, Winterset and Des Moines Railroad | | | 1911 | 1918 | N/A |
| Crooked Creek Railroad and Coal Company | | CNW | 1875 | 1916 | Fort Dodge, Des Moines and Southern Railroad |
| Davenport, Clinton and Eastern Railway | | CB&Q/ MILW | 1895 | 1901 | Davenport, Rock Island and North Western Railway |
| Davenport, Iowa and Dakota Railroad | | RI | 1882 | 1892 | Burlington, Cedar Rapids and Northern Railway |
| Davenport and North Western Railway | | MILW | 1876 | 1879 | Chicago, Milwaukee and St. Paul Railway |
| Davenport and Rock Island Railway Bridge Company | | CB&Q/ MILW | 1884 | 1895 | Davenport and Rock Island Bridge, Railway and Terminal Company |
| Davenport and Rock Island Bridge, Railway and Terminal Company | | CB&Q/ MILW | 1895 | 1898 | Davenport, Rock Island and North Western Railway |
| Davenport, Rock Island and North Western Railway | DRI | CB&Q/ MILW | 1898 | 1995 | Soo Line Railroad |
| Davenport and St. Paul Railroad | | MILW | 1868 | 1876 | Davenport and North Western Railway |
| Des Moines, Adel and Western Railroad | | MILW | 1875 | 1880 | Des Moines North Western Railway |
| Des Moines and Central Iowa Railroad | D&CI, DCI | CNW | 1922 | 1949 | Des Moines and Central Iowa Railway | Electric until 1949 |
| Des Moines and Central Iowa Railway | DCI | CNW | 1949 | 1983 | Chicago and North Western Transportation Company |
| Des Moines and Fort Dodge Railroad | | MSTL | 1874 | 1915 | Minneapolis and St. Louis Railroad |
| Des Moines, Indianola and Missouri Railroad | | RI | 1870 | 1876 | Iowa Southern and Missouri Northern Railroad |
| Des Moines, Iowa Falls and Northern Railway | | RI | 1899 | 1908 | St. Paul and Des Moines Railroad |
| Des Moines and Kansas City Railway | | CB&Q | 1888 | 1898 | Keokuk and Western Railroad |
| Des Moines and Knoxville Railway | | CB&Q | 1878 | 1901 | Chicago, Burlington and Quincy Railroad |
| Des Moines and Minneapolis Railroad | | CNW | 1877 | 1884 | Chicago and North Western Railway |
| Des Moines and Minnesota Railroad | | CNW | 1870 | 1877 | Des Moines and Minneapolis Railroad |
| Des Moines and Northern Railway | | MILW | 1889 | 1891 | Des Moines, Northern and Western Railway |
| Des Moines, Northern and Western Railroad | | MILW | 1895 | 1899 | Chicago, Milwaukee and St. Paul Railway |
| Des Moines, Northern and Western Railway | | MILW | 1891 | 1895 | Des Moines, Northern and Western Railroad |
| Des Moines North Western Railway | | MILW | 1880 | 1888 | Des Moines and Northwestern Railway |
| Des Moines and Northwestern Railway | | MILW | 1887 | 1891 | Des Moines, Northern and Western Railway |
| Des Moines, Osceola and Southern Railroad | | CB&Q | 1879 | 1887 | Des Moines and Kansas City Railway |
| Des Moines and St. Louis Railroad | | WAB | 1881 | 1899 | Wabash Railroad |
| Des Moines Southern Railway | | RI | 1901 | 1903 | Chicago, Rock Island and Pacific Railroad |
| Des Moines Terminal Company | | | 1902 | | |
| Des Moines Union Railway | DMU | | 1884 | 1989 | Norfolk and Western Railway |
| Des Moines Valley Railroad | | MSTL, RI | 1864 | 1873 | Des Moines and Fort Dodge Railroad, Keokuk and Des Moines Railway |
| Des Moines Western Railway | | CNW | | 1974 | Chicago and North Western Transportation Company |
| Des Moines Western Railway | | MILW | 1871 | 1874 | Des Moines, Adel and Western Railroad |
| Des Moines, Winterset and South Western Railroad | | RI | 1871 | 1879 | Iowa Southern and Missouri Northern Railroad |
| Dubuque, Bellevue and Mississippi Railway | | MILW | 1870 | 1871 | Chicago, Clinton and Dubuque Railroad |
| Dubuque and Dakota Railroad | | CGW | 1878 | 1887 | Minnesota and Northwestern Railroad |
| Dubuque and MacGregor Railway | | MILW | 1868 | 1869 | Dubuque and Minnesota Railway |
| Dubuque, Marion and Western Railroad | | MILW | 1860 | 1863 | Dubuque South Western Railroad |
| Dubuque and Minnesota Railroad | | MILW | 1877 | 1878 | Chicago, Clinton, Dubuque and Minnesota Railroad |
| Dubuque and Minnesota Railway | | MILW | 1869 | 1871 | Chicago, Dubuque and Minnesota Railroad |
| Dubuque and Northwestern Railway | | CGW | 1883 | 1886 | Minnesota and Northwestern Railroad |
| Dubuque and Pacific Railroad | | IC | 1853 | 1860 | Dubuque and Sioux City Railroad |
| Dubuque and Sioux City Railroad | | IC | 1860 | 1946 | Illinois Central Railroad |
| Dubuque South Western Railroad | | MILW | 1863 | 1881 | Chicago, Milwaukee and St. Paul Railway |
| Dubuque Western Railroad | | MILW | 1855 | 1861 | Dubuque, Marion and Western Railroad |
| Dunleith and Dubuque Bridge Company | | IC | 1867 | 1946 | Illinois Central Railroad |
| Eldora Railroad and Coal Company | | MSTL | 1866 | 1868 | Iowa River Railway |
| Fairfield and Ottumwa Railroad | | CB&Q | 1900 | 1901 | Chicago, Burlington and Quincy Railroad |
| Farmers Union Railroad | | | 1875 | 1875 | N/A |
| Forest City Southern Railway | | CNW | 1881 | 1882 | Chicago, Iowa and Dakota Railway |
| Fort Dodge, Des Moines and Southern Railroad | | CNW | 1906 | 1942 | Fort Dodge, Des Moines and Southern Railway |
| Fort Dodge, Des Moines and Southern Railway | FDDM | CNW | 1942 | 1983 | Chicago and North Western Transportation Company | Electric until 1955 |
| Fort Dodge and Fort Ridgeley Railroad | | MSTL | 1878 | 1881 | Minneapolis and St. Louis Railway |
| Fort Dodge and Fort Ridgeley Railroad and Telegraph Company | | MSTL | 1876 | 1878 | Fort Dodge and Fort Ridgeley Railroad |
| Fort Dodge and Omaha Railroad | | IC | 1898 | 1900 | Dubuque and Sioux City Railroad |
| Fort Madison, Farmington and Western Railroad | | CB&Q | 1869 | 1870 | Burlington, Fort Madison and Southwestern Railway |
| Fort Madison and Keokuk Railway and Transportation Company | | CB&Q | 1862 | 1867 | Keokuk and St. Paul Railway |
| Fort Madison and Northwestern Railway | | CB&Q | 1872 | 1890 | Chicago, Fort Madison and Des Moines Railway |
| Fort Madison, Oskaloosa and Northwestern Railway | | CB&Q | 1872 | 1872 | Fort Madison and Northwestern Railway |
| Fort Madison, West Point, Keosauqua and Bloomfield Railroad | | CB&Q | 1853 | 1857 | Iowa Southern Railroad |
| Galena and Chicago Union Railroad | | CNW | 1862 | 1864 | Chicago and North Western Railway |
| Gowrie and Northwestern Railway | | RI | 1899 | 1900 | Chicago, Rock Island and Pacific Railway |
| Great Northern Railway | GN | GN | 1907 | 1970 | Burlington Northern Inc. |
| Grinnell and Montezuma Railroad | | MSTL | 1875 | 1882 | Keithsburg, Grinnell and Dakota Railway |
| Guthrie and Northwestern Railroad | | RI | 1879 | 1890 | Chicago, Rock Island and Pacific Railway |
| Harlan and Kirkman Railway | | CNW | 1899 | 1900 | Chicago and North Western Railway |
| Hastings and Avoca Railroad | | CB&Q | 1870 | 1901 | Chicago, Burlington and Quincy Railroad |
| Humeston and Shenandoah Railroad | | CB&Q | 1881 | 1896 | Humeston and Shenandoah Railway |
| Humeston and Shenandoah Railway | | CB&Q | 1896 | 1901 | Chicago, Burlington and Quincy Railroad |
| Illinois Central Railroad | IC | IC | 1867 | 1972 | Illinois Central Gulf Railroad |
| Illinois Central Gulf Railroad | ICG | | 1972 | 1985 | Chicago Central and Pacific Railroad |
| I&M Rail Link | IMRL | | 1997 | 2002 | Iowa, Chicago and Eastern Railroad |
| Iowa Railroad | IRRC | | 1981 | 1987 | N/A |
| Iowa Railway | | MSTL | 1888 | 1888 | Iowa Central Railway |
| Iowa Railway, Coal and Manufacturing Company | | CNW | 1873 | 1887 | Chicago and North Western Railway |
| Iowa Central Railway | | MSTL | 1888 | 1912 | Minneapolis and St. Louis Railroad |
| Iowa Central Air Line Railroad | | CNW | 1853 | 1864 | Mississippi, Maquoketa and Northwestern Railroad |
| Iowa Central and Northwestern Railway | | MSTL | 1880 | 1882 | Central Iowa Railway |
| Iowa Central and Western Railway | | MSTL | 1898 | 1916 | Minneapolis and St. Louis Railroad |
| Iowa, Chicago and Eastern Railroad | ICE | | 2002 | 2008 | Dakota, Minnesota and Eastern Railroad |
| Iowa City and Western Railway | | RI | 1878 | 1902 | Burlington, Cedar Rapids and Northern Railway |
| Iowa Eastern Railroad | | MILW | 1872 | 1880 | Chicago, Milwaukee and St. Paul Railway |
| Iowa Falls and Sioux City Railroad | | IC | 1867 | 1888 | Dubuque and Sioux City Railroad |
| Iowa and Great Northern Railway | | GN | 1905 | 1910 | Great Northern Railway |
| Iowa Midland Railway | | CNW | 1870 | 1884 | Chicago and North Western Railway |
| Iowa and Minnesota Railroad | | RI | 1870 | 1883 | Cedar Rapids, Iowa Falls and Northwestern Railway |
| Iowa and Minnesota Railway | | CNW | 1866 | 1870 | Des Moines and Minnesota Railroad |
| Iowa, Minnesota and North Pacific Railway | | RI | 1871 | 1877 | Newton and Monroe Railroad |
| Iowa, Minnesota and Northwestern Railway | | CNW | 1898 | 1900 | Chicago and North Western Railway |
| Iowa and Missouri State Line Railroad | | CB&Q | 1859 | 1870 | Burlington and Southwestern Railway |
| Iowa Northern Railway | | | 1882 | 1901 | Colfax Northern Railroad |
| Iowa Northern Central Railroad | | CB&Q | 1867 | 1870 | Keokuk, Iowa City and Minnesota Railroad |
| Iowa and Omaha Short Line Railway | | | 1908 | 1916 | N/A |
| Iowa Pacific Railroad | | CGW | 1870 | 1879 | Dubuque and Dakota Railroad, Mason City and Fort Dodge Railroad |
| Iowa River Railway | | MSTL | 1868 | 1869 | Central Railroad of Iowa |
| Iowa and St. Louis Railway | | CB&Q | 1901 | 1903 | Chicago, Burlington and Quincy Railroad |
| Iowa Southern Railroad | ISR | | 1984 | 1989 | Council Bluffs and Ottumwa Railway |
| Iowa Southern Railroad | | CB&Q | 1857 | 1862 | Fort Madison and Keokuk Railway and Transportation Company |
| Iowa Southern Railway | | CNW | 1913 | 1920 | Chicago and North Western Railway |
| Iowa Southern Railway | | CB&Q | 1868 | 1870 | Missouri, Iowa and Nebraska Railway |
| Iowa Southern Junction Railroad | | CB&Q | 1858 | 1859 | Iowa Southern Railroad |
| Iowa Southern and Missouri Northern Railroad | | RI | 1876 | 1880 | Chicago, Rock Island and Pacific Railway |
| Iowa Southern Utilities Company | ISN, ISU | | 1916 | 1941 | Southern Iowa Railway |
| Iowa Southwestern Railroad | | RI | 1870 | 1872 | Chicago, Omaha and St. Joseph Railroad |
| Iowa and Southwestern Railway | | | | 1916 | N/A |
| Iowa South Western Railway | | CNW | 1880 | 1884 | Chicago and North Western Railway |
| Iowa Terminal Railroad | IAT | | 1961 | 1987 | Charles City Railway Line, Inc., Iowa Traction Railroad |
| Iowa Transfer Railway | | CB&Q/ CGW/ RI | 1906 | | |
| Kansas City, St. Joseph and Council Bluffs Railroad | | CB&Q | 1870 | 1901 | Chicago, Burlington and Quincy Railroad |
| Keithsburg Bridge Company | | MSTL | 1881 | 1901 | Iowa Central Railway |
| Keithsburg, Grinnell and Dakota Railway | | MSTL | 1882 | 1882 | Central Iowa Railway |
| Keokuk Railway and Improvement Company | | CB&Q | 1891 | 1900 | St. Louis, Keokuk and Northwestern Railroad |
| Keokuk and Des Moines Railway | | RI | 1874 | 1924 | St. Paul and Kansas City Short Line Railroad |
| Keokuk, Fort Des Moines and Minnesota Railroad | | MSTL, RI | 1853 | 1864 | Des Moines Valley Railroad |
| Keokuk and Hamilton Bridge Company | | TP&W | 1868 | | |
| Keokuk and Hamilton Mississippi Bridge Company | | | 1866 | 1868 | Keokuk and Hamilton Bridge Company |
| Keokuk, Iowa City and Minnesota Railroad | | CB&Q | 1870 | 1874 | Burlington and Northwestern Railway, Keokuk and North Western Railroad |
| Keokuk and Minnesota Railway | | CB&Q | 1869 | 1870 | Keokuk, Iowa City and Minnesota Railroad |
| Keokuk, Mount Pleasant and Muscatine Railroad | | CB&Q | 1855 | 1866 | Keokuk and St. Paul Railway |
| Keokuk, Mount Pleasant and Northern Railroad | | CB&Q | 1879 | 1881 | Keokuk and Northwestern Railroad |
| Keokuk and Northwestern Railroad | | CB&Q | 1881 | 1889 | Mount Pleasant and Keokuk Railroad |
| Keokuk and North Western Railroad | | CB&Q | 1876 | 1881 | Keokuk and Northwestern Railroad |
| Keokuk and St. Paul Railway | | CB&Q | 1867 | 1901 | Chicago, Burlington and Quincy Railroad |
| Keokuk Union Depot Company | | CB&Q/ RI/ TP&W/ WAB | 1890 | | | Still exists as a subsidiary of the Keokuk Junction Railway |
| Keokuk and Western Railroad | | CB&Q | 1886 | 1901 | Chicago, Burlington and Quincy Railroad |
| Keosauqua and Southwestern Railroad | | RI | 1880 | 1890 | Chicago, Rock Island and Pacific Railway |
| Kewash Railroad | KWTR | | 1983 | 1988 | N/A |
| Leon, Mount Ayr and Southwestern Railroad | | CB&Q | 1878 | 1901 | Chicago, Burlington and Quincy Railroad |
| Linn County Railway | | CNW | 1886 | 1887 | Chicago and North Western Railway |
| Manchester and Oneida Railway | | | 1900 | 1951 | N/A |
| Maple River Railroad | | CNW | 1876 | 1884 | Chicago and North Western Railway |
| Maple Valley Railway | | CNW | 1886 | 1887 | Chicago and North Western Railway |
| Maquoketa, Hurstville and Dubuque Railroad | | MILW | 1888 | 1903 | Chicago, Milwaukee and St. Paul Railway |
| Marshalltown and Dakota Railway | | CNW | 1895 | 1903 | Newton and Northwestern Railroad |
| Mason City and Fort Dodge Railroad | | CGW | 1881 | 1940 | Chicago Great Western Railroad |
| Mason City and Fort Dodge Railway | | CGW | 1902 | 1905 | Mason City and Fort Dodge Railroad |
| Mason City and Minnesota Railway | | MILW | 1870 | 1871 | Milwaukee and St. Paul Railway |
| McGregor and Missouri River Railway | | MILW | 1869 | 1880 | Chicago, Milwaukee and St. Paul Railway, Milwaukee and St. Paul Railway |
| McGregor and Sioux City Railway | | MILW | 1868 | 1869 | McGregor and Missouri River Railway, Milwaukee and St. Paul Railway |
| McGregor Western Railway | | MILW | 1863 | 1867 | Milwaukee and St. Paul Railway |
| Milwaukee, Chicago, Cassville and Montana Railroad | | MILW | 1871 | 1872 | Iowa Eastern Railroad |
| Milwaukee and Prairie du Chien Railway | | MILW | 1865 | 1867 | Milwaukee and St. Paul Railway |
| The Milwaukee Road, Inc. | MILW | MILW | 1985 | 1986 | Soo Line Railroad |
| Milwaukee and St. Paul Railway | | MILW | 1867 | 1874 | Chicago, Milwaukee and St. Paul Railway |
| Minneapolis and St. Louis Railroad | | MSTL | 1895 | 1944 | Minneapolis and St. Louis Railway |
| Minneapolis and St. Louis Railroad and Telegraph Company of Iowa | | MSTL | 1895 | 1895 | Minneapolis and St. Louis Railroad |
| Minneapolis and St. Louis Railway | MSTL | MSTL | 1939 | 1960 | Chicago and North Western Railway |
| Minneapolis and St. Louis Railway | | MSTL | 1881 | 1894 | Minneapolis and St. Louis Railroad and Telegraph Company of Iowa |
| Minnesota and Iowa Railway | | CNW | 1898 | 1900 | Chicago and North Western Railway |
| Minnesota and Iowa Southern Railway | | MSTL | 1878 | 1881 | Minneapolis and St. Louis Railway |
| Minnesota and Northwestern Railroad | | CGW | 1886 | 1887 | Chicago, St. Paul and Kansas City Railway |
| Mississippi, Maquoketa and Northwestern Railroad | | CNW | 1868 | 1871 | Iowa Midland Railway |
| Mississippi and Missouri Railroad | | RI | 1853 | 1866 | Chicago, Rock Island and Pacific Railroad |
| Mississippi River Railroad and Toll Bridge Company | | ATSF | 1886 | 1900 | Atchison, Topeka and Santa Fe Railway |
| Mississippi Valley and Western Railway | | CB&Q | 1871 | 1875 | St. Louis, Keokuk and North Western Railway |
| Missouri, Iowa and Nebraska Railway | | CB&Q | 1870 | 1886 | Keokuk and Western Railroad |
| Missouri Valley and Blair Railway and Bridge Company | | CNW | 1882 | 1920 | Chicago and North Western Railway |
| Moulton, Albia and Des Moines Railroad | | WAB | 1899 | 1899 | Wabash Railroad |
| Mount Pleasant and Keokuk Railroad | | CB&Q | 1889 | 1889 | St. Louis, Keokuk and Northwestern Railroad |
| Moville Extension Railway | | CNW | 1901 | 1901 | Sioux City and Pacific Railroad |
| Murray and Creston Railroad | | CB&Q | 1900 | 1901 | Chicago, Burlington and Quincy Railroad |
| Muscatine, Burlington and Southern Railroad | | RI | 1916 | 1925 | Burlington, Muscatine and Northwestern Railway |
| Muscatine and Iowa City Railway | | RI | 1915 | 1916 | N/A | Leased several lines from the Chicago, Rock Island and Pacific Railway |
| Muscatine North and South Railroad | | RI | 1893 | 1905 | Muscatine North and South Railway |
| Muscatine North and South Railway | | RI | 1905 | 1916 | Muscatine, Burlington and Southern Railroad |
| Muscatine Western Railroad | | RI | 1870 | 1872 | Burlington, Cedar Rapids and Minnesota Railway |
| Nebraska Railway | | CB&Q | 1875 | 1908 | Chicago, Burlington and Quincy Railroad |
| Nebraska City, Sidney and North Eastern Railway | | CB&Q | 1878 | 1901 | Chicago, Burlington and Quincy Railroad |
| New Sharon, Coal Valley and Eastern Railroad | | MSTL | 1880 | 1882 | Chicago, Burlington and Pacific Railroad |
| Newton and Monroe Railroad | | RI | 1877 | 1880 | Chicago, Rock Island and Pacific Railway |
| Newton and Northwestern Railroad | | CNW | 1902 | 1909 | Fort Dodge, Des Moines and Southern Railroad |
| Norfolk and Western Railway | N&W, NW | | 1964 | 1998 | Norfolk Southern Railway |
| Omaha Bridge and Terminal Railway Company | | IC | 1893 | 1946 | Illinois Central Railroad |
| Omaha and St. Louis Railroad | | WAB | 1896 | 1901 | Wabash Railroad |
| Omaha and St. Louis Railway | | WAB | 1887 | 1896 | Omaha and St. Louis Railroad |
| Ottumwa, Cedar Falls and St. Paul Railway | | CNW | 1883 | 1884 | Chicago and North Western Railway |
| Ottumwa Terminal Railroad | | | | 1989 | Council Bluffs and Ottumwa Railway |
| Red Oak and Atlantic Railroad | | CB&Q | 1870 | 1901 | Chicago, Burlington and Quincy Railroad |
| Sabula, Ackley and Dakota Railroad | | MILW | 1870 | 1872 | Milwaukee and St. Paul Railway |
| Sac City and Wall Lake Railroad | | CNW | 1877 | 1878 | Maple River Railroad |
| St. Joseph and Council Bluffs Railroad | | CB&Q | 1869 | 1870 | Kansas City, St. Joseph and Council Bluffs Railroad |
| St. Louis and Cedar Rapids Railway | | WAB | 1865 | 1873 | St. Louis, Ottumwa and Cedar Rapids Railway |
| St. Louis, Des Moines and Northern Railway | | MILW | 1881 | 1889 | Des Moines and Northern Railway |
| St. Louis, Keokuk and Northwestern Railroad | | CB&Q | 1887 | 1901 | Chicago, Burlington and Quincy Railroad |
| St. Louis, Keokuk and North Western Railway | | CB&Q | 1875 | 1887 | St. Louis, Keokuk and Northwestern Railroad |
| St. Louis, Keosauqua and St. Paul Railroad | | RI | 1873 | 1875 | Keosauqua and Southwestern Railroad |
| St. Louis, Ottumwa and Cedar Rapids Railway | | WAB | 1875 | 1887 | Wabash Western Railway |
| St. Paul and Des Moines Railroad | | RI | 1905 | 1911 | St. Paul and Kansas City Short Line Railroad |
| St. Paul and Kansas City Short Line Railroad | | RI | 1911 | 1948 | Chicago, Rock Island and Pacific Railroad |
| St. Paul and Sioux City Railroad | | CNW | 1879 | 1881 | Chicago, St. Paul, Minneapolis and Omaha Railway |
| Sioux City Bridge Company | | CNW | 1872 | 1956 | Chicago and North Western Railway |
| Sioux City and Dakota Railroad | | MILW | 1879 | 1881 | Chicago, Milwaukee and St. Paul Railway |
| Sioux City, Dakota and North Western Railway | | CNW | 1909 | 1910 | Chicago and North Western Railway |
| Sioux City and Northern Railroad | | GN | 1887 | 1900 | Willmar and Sioux Falls Railway |
| Sioux City and Pacific Railroad | | CNW | 1864 | 1901 | Chicago and North Western Railway |
| Sioux City and Pembina Railway | | MILW | 1870 | 1879 | Sioux City and Dakota Railroad |
| Sioux City and St. Paul Railroad | | CNW | 1866 | 1879 | St. Paul and Sioux City Railroad |
| Sioux City Terminal Railroad and Warehouse Company | | GN | 1889 | 1900 | Union Terminal Railway |
| Sioux City Terminal Railway | SCT | | 1907 | 1972 | N/A |
| Sioux Valley Railway | | CNW | 1887 | 1887 | Chicago and North Western Railway |
| Soo Line Railroad | SOO | CP | 1986 | 1997 | I&M Rail Link |
| Southern Industrial Railroad | SIRR | | 1964 | 1967 | N/A |
| Southern Iowa Railway | | | 1941 | 1965 | Southern Industrial Railroad |
| Southern Iowa Railway | | CNW | 1900 | 1901 | Chicago and North Western Railway |
| Southern Iowa Traction Company | | | 1910 | 1914 | Centerville, Albia and Southern Railway |
| Stacyville Railroad | | IC | 1897 | 1903 | Dubuque and Sioux City Railroad |
| Stanwood and Tipton Railway | | CNW | 1872 | 1884 | Chicago and North Western Railway |
| Tabor and Northern Railway | | | 1887 | 1934 | N/A |
| Tama and Toledo Railroad | | CNW | | 1953 | Chicago and North Western Railway | Electric until 1925 |
| Tarkio Valley Railroad | | CB&Q | 1880 | 1900 | Kansas City, St. Joseph and Council Bluffs Railroad |
| Toledo and Northwestern Railway | | CNW | 1869 | 1890 | Chicago and North Western Railway |
| Toledo, Peoria and Warsaw Railway | | TP&W | 1869 | 1880 | Toledo, Peoria and Western Railroad |
| Toledo, Peoria and Western Railroad | TP&W, TPW | TP&W | 1926 | 1983 | Atchison, Topeka and Santa Fe Railway |
| Toledo, Peoria and Western Railroad | | TP&W | 1879 | 1886 | Toledo, Peoria and Western Railway |
| Toledo, Peoria and Western Railway | TPW | | 1989 | 2001 | Keokuk Junction Railway |
| Toledo, Peoria and Western Railway | TP&W | TP&W | 1887 | 1927 | Toledo, Peoria and Western Railroad |
| Union Pacific Railroad | | UP | 1862 | 1880 | Union Pacific Railway |
| Union Pacific Railway | | UP | 1880 | 1898 | Union Pacific Railroad |
| Union Terminal Railway | | GN | 1900 | 1910 | Great Northern Railway |
| Wabash Railroad | WAB | WAB | 1937 | 1991 | Norfolk and Western Railway |
| Wabash Railroad | | WAB | 1889 | 1915 | Wabash Railway |
| Wabash Railway | | WAB | 1915 | 1941 | Wabash Railroad |
| Wabash Western Railway | | WAB | 1887 | 1889 | Wabash Railroad |
| Waterloo Railroad | WLO | IC/ RI | 1955 | | |
| Waterloo, Cedar Falls and Northern Railroad | | IC/ RI | 1944 | 1956 | Waterloo Railroad |
| Waterloo, Cedar Falls and Northern Railway | | IC/ RI | 1904 | 1944 | Waterloo, Cedar Falls and Northern Railroad | Electric 1912-1947 |
| Waukon and Mississippi Railroad | | MILW | 1875 | 1880 | Chicago, Clinton, Dubuque and Minnesota Railroad |
| Waverly Short Line | | RI | 1885 | 1902 | Burlington, Cedar Rapids and Northern Railway |
| Webster City and Southwestern Railroad | | CNW | 1883 | 1890 | Crooked Creek Railroad and Coal Company |
| Western Iowa Railroad | | CB&Q | 1884 | 1901 | Chicago, Burlington and Quincy Railroad |
| Willmar and Sioux Falls Railway | | GN | 1900 | 1907 | Great Northern Railway |
| Winona, Osage and Southwestern Railway | | CGW | 1891 | 1891 | Winona and Southwestern Railway |
| Winona and Southwestern Railway | | CGW | 1888 | 1894 | Winona and Western Railway |
| Winona and Western Railway | | CGW | 1894 | 1901 | Wisconsin, Minnesota and Pacific Railroad |
| Wisconsin, Iowa and Nebraska Railway | | CGW | 1882 | 1886 | Chicago, St. Paul and Kansas City Railway |
| Wisconsin, Minnesota and Pacific Railroad | | CGW | 1901 | 1920 | Chicago Great Western Railroad |
| Worthington and Sioux Falls Railroad | | CNW | 1879 | 1879 | St. Paul and Sioux City Railroad |
