Steve,
That can be either hard or easy. I bought mine a few months ago at the R&LHS Southern California Chapter's display during the LA County (Pomona) Fair. They had a number of back issues donated for fund raising sales; I don't recall if there were any additional copies of #116. I am sure that there are previously owned (used) copies out there.
More recent issues are available new from the Pacific Coast Chapter's Mile Post One store located in Folsom, CA Its URL is:
[mp1.com]
R&LHS members can buy copies of articles in back issues from the Society's archivist.
Also the R&LHS has individual rosters available to members.
The R&LHS purblishes its high quality "Railroad History" twice a year and a quarterly newsletter. The several chapters have their own newsletters.
I whole heartedly suggest membership to anyone interested in railroad and locomotive history. See the nationals' advertisement in TRAINS MAGAZINE or the websites for the Pacific Coast Chapter at
[www.mp1.com]
or the Southern California Chapter at
[www.trainweb.org]
Hope this helps.
Brian Norden