July 1921-April 1923 Figures Were Computed From Data On Straight Time, Number Of Hours Paid For, And Amounts Paid Since Figures With Only Two Digits Were Available In The Source. Source: Interstate Commerce Commission, Wage Statistics Of Class I Steam Railways In The United States, Monthly Issues.
This NBER data series m08055 appears on the NBER website in Chapter 8 at http://www.nber.org/databases/macrohistory/contents/chapter08.html.
NBER Indicator: m08055
Release: NBER Macrohistory Database
National Bureau of Economic Research, Straight Time Hourly Earnings, Professional, Clerical, and General Railroad Employees for United States [M08055USM052NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M08055USM052NNBR, February 11, 2016.