Series Is Presented Here As Two Variables--(1)--Original Data, 1889-1916 (2)--Original Data, 1911-1945 1911-1915 Data Are As Of June 1. 1916-1945 Data Are As Of December 31. Source: Interstate Commerce Commission, Annual Reports Of Statistics Of Railways In The United States
This NBER data series a01155b appears on the NBER website in Chapter 1 at http://www.nber.org/databases/macrohistory/contents/chapter01.html.
NBER Indicator: a01155b
Release: NBER Macrohistory Database
National Bureau of Economic Research, Steam Locomotives Available for United States [A0155BUSA481NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/A0155BUSA481NNBR/, July 3, 2015.