In addition to seeling back issues of the magazine "North Western Lines, the Chicago & North Western Historical Society's "Company store" sells some books that you might find interesting and worthwhile.
Two books on iron ore industry and mines in the context of the C&NW are published by the Society - this is pure "information" rather than text with photos but it might be helpful in documenting where relatives worked
For a more human interest type book, they sell "Life on a Locomotive" the story of one engineer, Buddy Williams, as told by his son but it names many names of colleagues and tells many stories. A somewhat similar book (with stories more than technical data about the C&NW) is "Life on the Shiny Iron" by Charles Bass. It is not available from the C&NWHS that I know of.
The C&NWHS published two excellent books with photos and information about facilities on the entire railroad -- turntables, roundhouses, coal tipples, that sort of thing - and of course Escanaba is in there but not solely Escanaba.
Patrick Dorin's old book on iron ore railroads is certainly worth seeking out.
The H Roger Grant history of the C&NW has much to say about Escanaba.
Although key scenes were filmed in Ishpeming rather than Escanaba, the wonderful movie "Anatomy of a Murder" gives a good flavor for C&NW railroading in that part of the Upper Peninsula of MI. And there are many other reasons to watch that film.
Dave Nelson