North American Class I Railroads

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North American Class I Railroads

In North American freight railroading, railroads are sorted into classes by size. The largest carriers are the Class I railroads: the handful of major systems that move the bulk of long-distance freight across the continent. Understanding who the Class I roads are, and how a railroad earns that designation, is a useful starting point for making sense of the industry's structure.

What "Class I" Means

The Class I classification is based on annual operating revenue. In the United States, the threshold is set by the Surface Transportation Board, the federal agency that oversees freight rail, and it is adjusted over time. A railroad whose operating revenue exceeds that threshold is designated Class I; smaller carriers fall into lower classes. The exact dollar figure is periodically revised, so the practical point to remember is that Class I status reflects scale: these are the railroads with the highest revenue and, generally, the most route mileage and the broadest reach.

Because the definition is revenue-based rather than fixed to a list of companies, the membership of the Class I group has changed over the decades. A long history of mergers has steadily reduced the number of Class I railroads, as once-independent systems combined into larger ones.

The Current Class I Freight Railroads

As of the mid-2020s, the Class I freight railroads of North America are commonly identified as six systems. In the United States:

  • Union Pacific (UP) - one of the largest railroads on the continent, operating across the western two-thirds of the United States.
  • BNSF Railway - a western system formed from the merger of the Burlington Northern and Santa Fe railroads, with an extensive network across the West and Midwest.
  • CSX - a major carrier serving the eastern United States.
  • Norfolk Southern - the other large eastern carrier, operating across much of the East and Southeast.

And the two Canadian-based systems, both of which also operate extensively in the United States:

  • Canadian National (CN) - a transcontinental Canadian railroad whose network also reaches deep into the U.S. Midwest and down to the Gulf of Mexico.
  • Canadian Pacific Kansas City (CPKC) - formed in 2023 when Canadian Pacific combined with the Kansas City Southern (KCS). The merger created the first single-line railroad linking Canada, the United States, and Mexico.

A Shifting Roster

The current list of six is a snapshot, not a permanent fixture. The creation of CPKC in 2023 is the most recent example of how the roster evolves: the Canadian Pacific-KCS combination reduced what had been a larger group of Class I roads and reshaped the competitive map of the continent. Earlier decades saw many more such mergers, each one folding familiar railroad names into larger systems. Anyone reading older references will encounter Class I railroads that no longer exist as independent companies, their networks now part of the surviving carriers above.

Why the Classification Matters

The Class I designation is more than a label. It affects regulatory reporting requirements and is widely used as shorthand for the major carriers when discussing freight volumes, industry economics, and network reach. When a source refers to "the Class I railroads," it is pointing to this small group of dominant systems that, together, handle the long-haul backbone of North American freight. The smaller regional and short-line railroads that connect to them - feeding traffic in and out - are essential too, but they fall outside the Class I tier by revenue.