Release: NBER Macrohistory Database
Source: Data Computed By NBER From Seasonally Adjusted Data For Series (Railroad Freight Tons Originated, Less Than Carload) Subtracted From Seasonally Adjusted Data For Series (Revenue Tons Originated,Class I Steam Railways)
This NBER data series q03068 appears on the NBER website in Chapter 3 at http://www.nber.org/databases/macrohistory/contents/chapter03.html.
NBER Indicator: q03068
National Bureau of Economic Research, Railroad Freight Tons Originated, Carload for United States [Q03068USQ455SNBR], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/Q03068USQ455SNBR, July 23, 2017.