Release: NBER Macrohistory Database
Data Exclude Switching And Terminal Companies. The Figure For January 1920 Was Computed By NBER By Dividing Loaded Cars By Loaded And Empty. Data For July-September Of 1922 Were Affected By A Shopmens' Strike. 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 1935-1942: "Freight Train Performance Of Class I Steam Railways In The United States"
This NBER data series m03043 appears on the NBER website in Chapter 3 at http://www.nber.org/databases/macrohistory/contents/chapter03.html.
NBER Indicator: m03043
National Bureau of Economic Research, Percent Loaded of Total Freight Car-Miles, Class I Railroads for United States [M03043USM156NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/M03043USM156NNBR, July 30, 2016.