@Gary Marsh posted:Hi hot water I purchased this book from Kalmbach Media about the big Boy's and it has lots of good information on them. Hope this answers your question on the cab numbers.
Thanks, however I don't need the answers, as I was asking if the REST of you folks know what those numbers indicate! I worked as a Contract Fireman for the UP Steam Program for some 17 years (retiring at the end of 2010), and we got those same questions every place we stoped, especially on Challenger 3985.