in 1972 (?) i had a boyfriend in chicago that did maintenance on the tracks for the ? railroad. (rock island ? my era of the sixties carried on for a while).  he ran heavy equipment for clearing snow  and to do maintenance/rebuilding of the tracks , and he said then the tracks were in terrible shape and surprised not more derailments.  the cars themselves, the bed, the ties, the rails - all bad shape.  chicago was a railroad yard!  between all the industry, timber from the north and the stockyards - there are tracks everywhere and chicago was the gateway to the west..