Release: NBER Macrohistory Database
Data Exclude Switching And Terminal Companies. The Unadjusted Figures For January-March 1920 Were Computed By NBER. Beginning In 1935, The Source Title Includes The Statement That "Train-Switching Hours At Way Stations" Are Included In The Data. Source: Interstate Commerce Commission, Data For 1920-1934: "Freight And Passenger Service Operating Statistics Of Class I Steam Railways In The United States"; Data For 1935-1943: "Freight Train Performance Of Class I Steam Railways In The United States"
This NBER data series m03049 appears on the NBER website in Chapter 3 at http://www.nber.org/databases/macrohistory/contents/chapter03.html.
NBER Indicator: m03049
National Bureau of Economic Research, Freight Train-Hours, Class I Railroads for United States [M03049USM606NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/M03049USM606NNBR, January 19, 2018.