Data Cover "Large Steam Roads" For 1917-1919 And "Class I Steam Railways" For 1920-1942. Data Cover Switching And Terminal Companies From 1917-1931 And Exclude Them Thereafter. Data For 1917-1934 Were Computed By Summing Three Items -- Uncollectable Railway Revenues, Equipment Rent, And Joint Faclity Rents. Data For 1935-1942 Were Computed By Summing Only Items Two And Three. Source: Interstate Commerce Commission, Data For 1917-19: "Operating Revenue And Expenses Of Large Steam Roads By Months", July 1914-December 1919", Pp. 10-15. Data For 1920-1942: "Operating Revenues And Operating Expenses Of Class I Steam Railways In The United States".
This NBER data series m03060 appears on the NBER website in Chapter 3 at http://www.nber.org/databases/macrohistory/contents/chapter03.html.
NBER Indicator: m03060
Release: NBER Macrohistory Database
National Bureau of Economic Research, Railway Equipment and Joint Facility Rents, Net, Class I Railroads for United States [M03060USM144NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M03060USM144NNBR/, August 29, 2015.