NBER Computed Data By Adding Figures For The Respective Groups Of Employees In Road Freight Service, Division Vi-B:"Transportation, Train And Engine." Source: NBER Computed Data From Interstate Commerce Commission, Wage Statistics Of Class I Steam Railroads In The United States, Monthly.
This NBER data series m08164 appears on the NBER website in Chapter 8 at http://www.nber.org/databases/macrohistory/contents/chapter08.html.
NBER Indicator: m08164
Release: NBER Macrohistory Database
National Bureau of Economic Research, Road Passenger Service, Overtime for United States [M08164USM568NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M08164USM568NNBR/, July 29, 2015.