I wonder if there is any more reference information about the history of the Empire Mine in Mackay, Idaho. It had initially operated with 36" electric locomotive, but later used a Shay. I had debated attaching this item to the older thread about electric traction and trolley cars, but this mine operation might generate a bunch of interest on its own. A little bit of information can be found in the link below.
http://mackayidaho1.blogspot.com/2012/03/blast-form-past-mackay-idahos-empire.html
For those of you interested in narrow gauge traction, you may wish to check out this yahoo group:
http://groups.yahoo.com/group/NG-Traction
Regards
O. Anderson