Release: NBER Macrohistory Database
The Seven Railroads Are: (1)--Pennsylvania Railroad (2)--Pittsburgh, Fort Wayne, And Chicago R.R. (3)--New York Central R.R. (4)--Lake Shore R.R. (5)--Michigan Central R.R. (6)--Boston And Albany R.R. (7)--New York,Lake Erie And Western R.R. Data For 1887-91 Were Computed By Adding Ton-Miles Of The Seven Individual Railroads. Source: Poor'S Manual Of Ralroads, 1888, P. Xxvii-Xxix; 1889, P. Viii; And Volumes For 1890, 1891, And 1892
This NBER data series a03003i appears on the NBER website in Chapter 3 at http://www.nber.org/databases/macrohistory/contents/chapter03.html.
NBER Indicator: a03003i
National Bureau of Economic Research, Tons of Freight Carries One Mile, Seven Railroads for United States [A0303IUSA253NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/A0303IUSA253NNBR, July 23, 2016.