Data For 1907-1914 And 1916-1924 Are Identical To The Data In Series "Revenue And Non-Revenue Net Ton-Miles Of Freight Hauled" And Could Be Considered Additional Variable Segments. Data At Least Until 1909 Are Based On A Two Month Moving Average Placed In The Second Month. Source: Babson Statistical Organization, Inc.
This NBER data series m03003 appears on the NBER website in Chapter 3 at http://www.nber.org/databases/macrohistory/contents/chapter03.html.
NBER Indicator: m03003
Release: NBER Macrohistory Database
National Bureau of Economic Research, Railroad Freight Ton-Miles, Revenue for United States [M03003USM253SNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M03003USM253SNBR, May 27, 2016.