Data For Class I Railways Excludes Switching And Terminal Companies From 1907-October 1910; Thereafter They Are Included. Data For 1907-October 1910 Cover Class A Railroads Which Include Large Roads -- Roads Operating A Mileage In Excess Of 250 Miles Or Having Annual Operating Revenues Of More Than One Million Dollars. Included In This Class, However, Are Small Roads Subject To Control, Direct Or Indirect, Of Large Roads As Defined Here. In November 1910 There Occurred A Change In Classification -- Class I Railroads Are All Steam Railway Companies Whose Operating Revenues Exceeded One Million Dollars. These Data Are Not Strictily Comparable With Previous Figures. Revised Data When Provided Have Been Used, With The Exceptions Of July-October 1910 And January 1913-June 1914. Source: Interstate Commerce Commission, Bureau Of Statistics, Data For 1907-June 1914: Bulletin Of Revenues And Expenses Of Steam Roads In The United States, No. 5, P. 12; No. 18, P. 12; No. 31, P. 12; Nos. 32-69. Data For July 1914-1919: "Operating Revenues And Expenses Of Large Steam Railroads, July 1914-December 1919". Data For 1920-1956: "Operating Revenues And Operating Expenses Of Class I Steam Railways In The United States", Monthly.
This NBER data series m03016b appears on the NBER website in Chapter 3 at http://www.nber.org/databases/macrohistory/contents/chapter03.html.
NBER Indicator: m03016b
Release: NBER Macrohistory Database
National Bureau of Economic Research, Operating Revenues of Railroads, Freight for United States [M0316BUSM144NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M0316BUSM144NNBR, May 5, 2016.