History

The North American railroad network is considered in the world for the movement of freight, and from its origins has been primarily oriented towards the needs of shippers over passenger travelers. 

The rail network reached its peak in the United States in 1916, with 254,037 miles of track, but the rise of inexpensive automobile and air travel in the first half of the twentieth century threatened the dominance of rail as a mode of travel for both passengers and goods, particularly following massive public investments in road and airport infrastructure during and after the Second World War. Railroads in this period were also subject to regulation which hampered their ability to respond to the changing environment. They were also required to operate unprofitable passenger service, racking up losses equivalent to $1.4 billion (in 2019 dollars). 

By the late 1960s, passenger travel was at risk of disappearing and in 1970, Congress passed the Rail Passenger Service Act of 1970, which relieved railroads of their obligation to provide unprofitable inter-city passenger rail service and created the National Railroad Passenger Corporation, now known as Amtrak. In exchange, railroads were required to give Amtrak trains dispatch preference over freight trains, and accommodate Amtrak operations at an incremental cost wherever they sought to increase service, without charging fixed or overhead costs.

In 1980, the Staggers Act was passed, loosening regulation and enabled railroads to be more competitive with the trucking industry. The Act's passage resulted in massive consolidation of railroad companies and easier discontinuance of unprofitable lines, driving track mileage down by almost 30% through the 1990s. 

Today, there are six Class I freight rail companies that combined own over 165,000 route miles in the United States and Canada:

•  BNSF Railway (BNSF)

• Canadian National Railway (CN)

• Canadian Pacific Kansas City (CP)

• CSX Transportation (CSX)

• Norfolk Southern Railway (NS)

• Union Pacific Railroad (UP). 

Class I railroads are defined as having annual revenues greater than $505 million (in 2019 inflation-adjusted terms). Of these, UP and BNSF are the largest and constitute a duopoly over rail infrastructure in the Western, Midwestern and Southern United States. In addition, there are numerous regional and short line or local railroads which move roughly a third of rail freight volume and maintain the remainder of inter-city route miles not owned by Class I companies.

Amtrak and VIA Rail, the national inter-city passenger carriers in the United States and Canada, would also be included as Class I railroads by revenue, but each owns less than 3 percent of the tracks along which it operates. Forty percent of Amtrak ridership was on the Northeast Corridor (NEC) in 2022, with most of the remainder on its 27 state-supported inter-city routes, the majority of which are 100-400 miles in length. There are also several dozen independent commuter rail agencies that run on freight railroad tracks or right-of-way.