Chapter 7: Workingmen, footnote 22, page 285 Ch7 fn. 22 p. 285 Tags: Discursive, Manuscript Collections, Published Letters/Correspondence, Histories and Biographies, Labor, Corporate and Business Organization, Technology By 1891 75 percent to 80 percent of the Northern Pacific freight cars had air brakes. Usselman, Regulating Railroad Innovation, 130-38, 280-85. Aldrich, Death Rode the Rails, 114-15. White, American Freight Car, 539. W. S. Mellen to Villard, Feb. 23, 1891, NP, LRR, PV, 137.H.5.8 (F).