Series Is Presented Here As Three Variables--(1)--Original Data, 1870-1926 (2)--Original Data, 1922-1942 (3)--Original Data, 1941-1955. Source: Data Were Computed By NBER From Seasonally Adjusted Data Of Orders For Passenger Cars, Freight Cars, And Locomotives Using Fixed Weights.
This NBER data series q06090a appears on the NBER website in Chapter 6 at http://www.nber.org/databases/macrohistory/contents/chapter06.html.
NBER Indicator: q06090a
Release: NBER Macrohistory Database
National Bureau of Economic Research, Index of Orders of Railroad Equipment for United States [Q0690AUSQ336NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/Q0690AUSQ336NNBR, February 13, 2016.