Scope and arrangement
Collection consists of mainly engineering papers with some personal papers of Arnold. Correspondence, 1918-1922, 1933-1941, includes business letters concerning engineering, railroads and his consulting firm; and personal letters concerning alumni activities at Hillsdale College, civic affairs in Chicago, and family matters. Nearly one half of the collection is made up of papers, 1898-1912, relating to Arnold's work for the New York Central Railroad and includes correspondence, reports, maps, specifications, drawings, and photographs. There are similar papers for other railroad companies Arnold worked with and scrapbooks concerning electrical engineering and Arnold's consulting work for various cities. Also, biographical papers; appointment and address books, 1887-1902, 1924-1925; engineering notebooks; and personal scrapbooks.