Railroads in North America are classified by the Association of American Railroads as Class 1, Class 2 and Class 3 in terms of size. The classification has always been by means of annual operating revenue; the exact revenues required to be in each class have varied through the years since they have adjusted for inflation. There was a time when one million dollars annual operating revenue was the definition, but that was back when a million dollars was real money.
Currently, a Class 1 railroad has an operating revenue exceeding $255.9 million. The exact setting of the cut-off figure has always been as much a political decision as anything else; there have always been rumors of the powerful Class 1 companies voting to increase the cut-off to deny an upstart membership of their exclusive "club".
The current Class 1 railroads in North America are the:
- Burlington Northern Santa Fe Railway (BNSF)
- Canadian National (CN)
- Canadian Pacific Railway (CP)
- CSX Transportation (CSX)
- Kansas City Southern Railway (KCS)
- Norfolk Southern Railway (NS)
- Union Pacific Railroad (UP)