Series Is Presented Here As Two Variables--(1)--Original Data, 1890-1916 (2)--Original Data, 1916-1943. Data Are For Class I, Ii, And Iii Railways. The Year End Is June 30. Source: Interstate Commerce Commission, "Statistics Of Railways In The United States For 1943, " P. 150, Published 1945
This NBER data series a03003ca appears on the NBER website in Chapter 3 at http://www.nber.org/databases/macrohistory/contents/chapter03.html.
NBER Indicator: a03003ca
Release: NBER Macrohistory Database
National Bureau of Economic Research, Railroad Revenue Freight Ton-Miles for United States [A033CAUSA239NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/A033CAUSA239NNBR/, September 1, 2015.