Series Is Presented Here As Two Variables--(1)--Original Data, 1907-1917 (2)--Original Data, 1915-1944. The Railroads Included In These Data Are The Same Throughout, Except That The Actual Number Of Roads Decreased Due To Consolidations, From About 175 To 118. The Figures For The Periods, 1907-1917, 1918-1924, 1920-1923, However, Are Comparable (Letter From The Ara, October 1934.) Data Are The Average Of Bi-Weekly Statistics Through May 1941. Beginning In June 1941, Data Represent Daily Averages For The Week Ending On The Last Saturday Of The Month. Source: Data For 1918-1924: American Railway Association, Annual Bulletins Of 1922-1924. Data For 1920-1928: U.S. Department Of Commerce, Survey Of Current Business, May 1922; August 1924; 1932 Supplement; Following Issues. Data For 1929-April 1934: Ara, Weekly Information Bulletin. Data For May 1934-1944: Ara, "Revenue Freight Loaded And Received From Connections."
This NBER data series m03009b appears on the NBER website in Chapter 3 at http://www.nber.org/databases/macrohistory/contents/chapter03.html.
NBER Indicator: m03009b
Release: NBER Macrohistory Database
National Bureau of Economic Research, Freight Car Surplus for United States [M0309BUSM543SNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M0309BUSM543SNBR, February 12, 2016.