Figures in circles represent the number of daily scheduled weekday passenger trains in both directions as shown in timetables in effect during January 1940. "Figure 4." Also appeared in author's Ph. D. dissertation (University of Chicago, 1943): The railway pattern of metropolitan Chicago.; Scale [ca. 1:230,000]; Master and use copy. Digital master created according to Benchmark for Faithful Reproductions of Monographs and Serials, Version 1. Digital Library Federation, December 2002.
