Picked up a resistance soldering unit (American Beauty 100W) on the weekend. Tried it out on some scraps of brass, then set forth assembling an Echo Mountain Models S-scale, round roof C-16 cab that I purchased (on spec) some time ago.
I noticed a major improvement in the ease of assembly and finished quality of the kit compared to my efforts with the Meridian Models quarry wagon. From brief examination of old photos, the cab appears to be appropriate for RGS #9. If I can locate the proper plans for this locomotive I may attempt to construct an Sn3 engine. Given the amount of information available for the Colorado roads, this shouldn't be too much of a chore. I just have about a hundred other projects to tackle first.