Data Are Based On Reports From The Association Of American Railroads For Principal Nonagricultural Commodities As Derived From Shippers' Reports Of Actual And Expected Car Needs. Data For 1927-1939 Cover Sixteen Components; For The First-Third Quarter Of 1946 Cover Seventeen Components; For The Fourth Quarter Of 1946 To 1958 Cover Nineteen Components. Source: G.H. Moore, Business Indicators, Vol. 2, NBER, Pp. 166-167
This NBER data series q16098 appears on the NBER website in Chapter 16 at http://www.nber.org/databases/macrohistory/contents/chapter16.html.
NBER Indicator: q16098
Release: NBER Macrohistory Database
National Bureau of Economic Research, Diffusion Index, Freight Car loadings, Nineteen Commodity Groups, Four Quarter Span for United States [Q16098USQ509NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/Q16098USQ509NNBR/, July 30, 2015.