Series Is Presented Here As Two Variables--(1)--Original Data, 1870-1924 (2)--Original Data, 1924-1950. Source: Annual Statistical And Outlook Issues Of Railway Age.
This NBER data series q06027b appears on the NBER website in Chapter 6 at http://www.nber.org/databases/macrohistory/contents/chapter06.html.
NBER Indicator: q06027b
Release: NBER Macrohistory Database
National Bureau of Economic Research, Orders For Freight Cars Placed By American Railroads For Domestic Use for United States [Q0627BUSQ477NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/Q0627BUSQ477NNBR/, December 1, 2015.