Series Is Presented Here As Five Variables--(1)--Original Data, 1870-1879 (2)--Original Data, 1879-1886 (3)--Original Data, 1886-1890 (4)--Original Data, 1890-1902 (5)--Original Data, 1902-1909 The Number Of Companies Changes Covered Changes For Each Time Segment. Source: Babson Statistical Organization, Inc., Direct From Files.
This NBER data series m03015bb appears on the NBER website in Chapter 3 at http://www.nber.org/databases/macrohistory/contents/chapter03.html.
NBER Indicator: m03015bb
Release: NBER Macrohistory Database
National Bureau of Economic Research, Railroad Gross Earnings for United States [M035BBUSM144NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M035BBUSM144NNBR/, November 29, 2015.