Railroad classes
In the United States, railroads are classified as Class I, II or III, as established by the Interstate Commerce Commission (ICC) for the year ending June 30, 1911.
Background
Initially, the ICC defined a classification system by annual gross revenue taken in by each entity. Class I railroads had an annual operating revenue of at least $1 million, while Class III railroad incomes were under $100,000 per annum. All such corporations were subject to reporting requirements on a quarterly or annual schedule. If a railroad slipped below its class qualification threshold for a period, it was not necessarily demoted immediately. For instance, in 1925, the ICC reported 174 Class I railroads, 282 Class II railroads, and 348 Class III railroads.
Since dissolution of the ICC in 1996, the Surface Transportation Board (STB) has become responsible for defining criteria for each railroad class. The bounds are typically redefined every several years to adjust for inflation and other factors.
