The following is a brief history of the North American rail system, mainly through major changes to Class I railroads, the largest class by operating revenue.

1977 The Virginia and Maryland Railroad replaces Conrail on most of the old New York, Philadelphia and Norfolk Railroad. Operations are transferred to the Eastern Shore Railroad in 1981Lewis, p. 115 and to the Bay Coast Railroad in 2006. October 1: The Michigan Interstate Railway (Class I) begins operating on the former route of the Ann Arbor Railroad. They take over from Conrail on tracks owned by the state of Michigan.Lewis, pp. 24, 315-316 December 1: The number of Class I railroads goes up by one, from 58 to 59, due to the start-up of the Michigan Interstate Railway.ICC (1976, 1977)

1978 April 1: Crown corporation Via Rail Canada takes over operations of intercity passenger trains from the Canadian National Railway and Canadian Pacific Ltd. October 24: The Penn Central Corporation emerges from reorganization as a real estate company. It has given up its one-sixth share of the Richmond, Fredericksburg and Potomac Railroad. November 1: The Missouri-Illinois Railroad is merged into parent Missouri Pacific Railroad.Moody's (1988), p. xxv December 31: The ICC raises the minimum operating revenue from $10 million to $50 million effective January 1, 1978, dropping seventeen railroads to Class II: Bangor and Aroostook Railroad Canadian Pacific Lines in Maine Central Vermont Railway (Canadian National Railway subsidiary) Chicago and Illinois Midland Railway Detroit and Toledo Shore Line Railroad Duluth, Winnipeg and Pacific Railway (Canadian National Railway subsidiary) Georgia Railroad (Seaboard Coast Line Railroad subsidiary) Georgia Southern and Florida Railway (Southern Railway subsidiary) Illinois Terminal Railroad Maine Central Railroad Michigan Interstate Railway Missouri-Illinois Railroad (Missouri Pacific Railroad subsidiary) Norfolk Southern Railway (Southern Railway subsidiary) Northwestern Pacific Railroad (Southern Pacific Transportation Company subsidiary) Richmond, Fredericksburg and Potomac Railroad Texas Mexican Railway Toledo, Peoria and Western Railroad The Auto-Train Corporation and National Railroad Passenger Corporation (Amtrak) are also removed from the list, which now only includes freight carriers, reducing the number of Class I railroads from 59 at the end of 1977 to 40 as of December 31, 1978.

1979 The Spokane, Portland and Seattle Railway is dissolved, its property going to lessee Burlington Northern Inc. November 1: The San Diego Metropolitan Transit Development Board purchases control of the San Diego and Arizona Eastern Railway (no longer Class I) from parent Southern Pacific Transportation Company, which continues to operate east of Plaster City. Freight service west of Plaster City will be operated by several companies, most recently the Carrizo Gorge Railway and San Diego and Imperial Valley Railroad.

1980 The Colorado and Wyoming Railway (no longer Class I) abandons its operations in Wyoming. March 1: The Chicago, Milwaukee, St. Paul and Pacific Railroad, in trusteeship since February 13, 1978,Moody's (1980), p. 891 abandons all operations west of Miles City, Montana. Very little of this trackage is taken over by other railroads. March 31: After a bankruptcy that started on March 17, 1975, and directed operation by the Kansas City Terminal Railway since October 5, 1979, the Chicago, Rock Island and Pacific Railroad shuts down entirely.Moody's (1984), p. 901 Over the next few years, other railroads will buy large portions of the Rock Island's system, most notably the Iowa Interstate Railroad (Chicago-Council Bluffs), Chicago and North Western Transportation Company (Spine Line), Missouri-Kansas-Texas Railroad subsidiary Oklahoma, Kansas and Texas Railroad (OKT Line), and Southern Pacific Transportation Company subsidiary St. Louis Southwestern Railway (Tucumcari Line). The Fort Worth and Denver Railway (Chicago, Burlington and Quincy Railroad system) becomes sole owner of the Joint Texas Division, formerly owned by the Burlington-Rock Island Railroad until 1964 and then equally by the two companies. June 24: The Grand Trunk Western Railroad buys control of the Detroit, Toledo and Ironton Railroad from the Penn Central Corporation. September 2: The New York, Susquehanna and Western Railway begins operating the former New York, Susquehanna and Western Railroad (no longer Class I), which filed for bankruptcy in January 1976.Moody's (1992), p. 442 November 1: Chessie System, Inc. and Seaboard Coast Line Industries merge to form the CSX Corporation,Moody's (1992), p. 421 parent of the Atlanta and West Point Railroad (no longer Class I), Baltimore and Ohio Railroad, Chesapeake and Ohio Railway, Clinchfield Railroad, Georgia Railroad, Louisville and Nashville Railroad, Seaboard Coast Line Railroad, Staten Island Railroad (no longer Class I), Western Railway of Alabama (no longer Class I), and Western Maryland Railway. November 21: The St. Louis-San Francisco Railway merges into Burlington Northern Inc.Moody's (1992), p. 12

1981 Burlington Northern Inc. merges subsidiaries Oregon Electric Railway (no longer Class I) and Oregon Trunk Railway (never Class I) into a new subsidiary, Burlington Northern (Oregon-Washington), Inc. January 12: The Atchison, Topeka and Santa Fe Railway acquires full control of the Toledo, Peoria and Western Railroad (no longer Class I) by buying the Penn Central Corporation's 50% share.Moody's (1992), p. 403 April 13: The Grand Trunk Western Railroad gains control of the Detroit and Toledo Shore Line Railroad (no longer Class I) by buying the 50% share owned by the Norfolk and Western Railway.Moody's (1992), p. 237 April 30: The Auto-Train Corporation (no longer Class I) ceases operations. Amtrak's Auto Train replacement will begin on October 30, 1983. May 14: Burlington Northern Inc. is renamed Burlington Northern Railroad. June 8: The Quanah, Acme and Pacific Railway (no longer Class I) merges into parent Burlington Northern Railroad.Moody's (1984), p. xxiii June 16: Guilford Transportation Industries purchases the Maine Central Railroad (no longer Class I). August: The Hooper-Myron Corporation, an affiliate of the Kankakee, Beaverville and Southern Railroad (not Class I), buys a portion of the old Chicago, Terre Haute and Southeastern Railway (ex-Chicago Southern Railway) between Hooper and Danville, Illinois from the Chicago, Milwaukee, St. Paul and Pacific Railroad.Lewis, p. 165 The rest of the old Chicago Southern has been abandoned, while the remnant of the CTH&SE in Indiana was sold in 2006 to the Indiana Rail Road. September 1: The Norfolk and Western Railway acquires the property of the Illinois Terminal Railroad (no longer Class I), formerly controlled jointly by 11 railroads (two of which were part of the N&W system).Moody's (1990), p. 64 October 1: The Detroit and Toledo Shore Line Railroad (no longer Class I) is merged into parent Grand Trunk Western Railroad. December 31: The Colorado and Southern Railway is merged into parent Burlington Northern Railroad.

1982 In preparation for common control with the Norfolk and Western Railway by the Norfolk Southern Corporation, Southern Railway subsidiary Norfolk Southern Railway (no longer Class I) is renamed Carolina and Northwestern Railway, a company it had merged with in 1974. The Providence and Worcester Railroad (not Class I) expands its operations to include Amtrak's Northeast Corridor between Pawtucket, Rhode Island and Old Saybrook, Connecticut, a former main line of the New York, New Haven and Hartford Railroad and most recently Conrail. In 1991 these freight rights are extended from Old Saybrook to East Haven.Lewis, p. 257 The New York, Susquehanna and Western Railway (no longer Class I) buys several lines from Conrail. This includes most of the old Syracuse, Binghamton and New York Railroad and a piece of the old Lehigh and Hudson River Railway between Sparta, New Jersey and Warwick, New York. After the NYS&W rehabilitates its trackage between Butler and Sparta, the latter becomes part of its main line in 1986. January 1: The Akron, Canton and Youngstown Railroad (no longer Class I) is merged into the Norfolk and Western Railway, its owner since 1964. February 20: Chesapeake and Ohio Railway (C&O) ceased operations and abandoned the railroad line connecting Manistee, Traverse City, and Petoskey. The segments from Grawn to Williamsburg and Charlevoix to Petoskey were subsequently acquired by the state of Michigan and operated under the Michigan Northern Railway (MIGN). The MIGN was later absorbed by the Tuscola and Saginaw Railway, which assumed responsibility for the aforementioned sections. March 31: The Chicago, Milwaukee, St. Paul and Pacific Railroad, in trusteeship since February 13, 1978, abandons all operations west of Ortonville, Minnesota. The Burlington Northern Railroad takes over operations on much of this trackage. June 1: The Norfolk Southern Corporation takes control of the Norfolk and Western Railway and Southern Railway.Moody's (1992), p. 94 June: The Soo Line Railroad gains control of the Minneapolis, Northfield and Southern Railway (no longer Class I).Moody's (1992), p. 223 October: The Michigan Interstate Railway (no longer Class I) discontinues operations on the former Ann Arbor Railroad north of Ann Arbor. The Tuscola and Saginaw Bay Railway takes over from Ann Arbor north to Alma, and the Michigan Northern Railway operates the remainder to Frankfort until 1983, when it too goes to the T&SB. The latter company is renamed Great Lakes Central Railroad in 2006. November 4: The Seaboard Coast Line Railroad acquires the rail assets of the Georgia Railroad and Banking Company, and absorbs lessee Georgia Railroad (no longer Class I), jointly controlled by the SCL and subsidiary Louisville and Nashville Railroad.Moody's (1984), p. xxii December 22: The Union Pacific Railroad gains control of the Missouri Pacific Railroad and Western Pacific Railroad.Moody's (1992), p. 122 December 31: The Fort Worth and Denver Railway is merged into parent Burlington Northern Railroad.

1983 The Tuscola and Saginaw Bay Railway (renamed Great Lakes Central Railroad in 2006), which operates the old Ann Arbor Railroad between Ann Arbor and Alma, expands its operations north to Frankfort and on ex-Grand Rapids and Indiana Railway trackage north of Cadillac, replacing the Michigan Northern Railway.Lewis, p. 316 The Montour Railroad (no longer Class I) ceases operations.Lewis, p. 359 The Nevada Northern Railway (no longer Class I) ceases operations. The Northern Nevada Railroad will resume freight service in January 1995,Lewis, p. 230 but in June 1996 the BHP Nevada Railroad will take over until July 1999, when freight is again discontinued. January 1: The CSX Corporation merges subsidiaries Seaboard Coast Line Railroad and Louisville and Nashville Railroad to form the Seaboard System Railroad.Moody's (1990), p. 273 February 11: The Clinchfield Railroad, an unincorporated entity organized jointly by the Atlantic Coast Line Railroad and subsidiary Louisville and Nashville Railroad to operate the Carolina, Clinchfield and Ohio Railway under lease, is dissolved, as both lessees have merged into the Seaboard System Railroad.Moody's (1983), p. 725 May 1: The Baltimore and Ohio Railroad begins operating the lines of subsidiary Western Maryland Railway.Moody's (1986), p. 668 May 31: The New Orleans Great Northern Railway merges into lessee Illinois Central Gulf Railroad.Moody's (1992), p. 32 July 1: Guilford Transportation Industries purchases the Boston and Maine Corporation, bankrupt since March 1970.