This group is open to all who are interested in American OO gauge model trains, which were primarily manufactured in the period 1935-55 by companies including Lionel, Scale-Craft, Nason Railways, Graceline, Famoco, Schorr, J-C Models, Picard, and many other smaller firms. American OO is 4mm scale (1/76) running on 19mm (3/4 inch) gauge track, just about half way between HO and S scales in size. This scale is also sometimes referred to as American 00 (with two zeros), but most published sources use the term American OO, pronounced "double O."

The photo at right was taken on the layout of John Ericson, showing a Scale-Craft 4-6-0 with a Nason 2-8-0 tender, freight cars by Famoco and Scale-Craft, and diesels kitbashed from overscale HO models. The track is handlaid with Code 100 rail.

This group welcomes all with an interest in building, collecting, and operating American OO gauge models.