One upon a time, seems there was this guy called Walt Disney and he and his buddy named Kimball wanted to build a backyard railroad. They went to a local west coast machine shop with drawings and cash. The builder asks what size, they looked at one another and said about his big! 7 1/2 inch. From that point on it became known as west coast scale. Such is the legend, how true is it? One can only guess!
Of the bigger RMI engines the ones that show up here the most are the RMI Prairies. Since we no longer run coal or oil fired they are are now all propane 7 1/2 inch gauge. TMRR.ORG
Right now we are having our annual Narrow Gauge Meet (2 1/2 inch scale and 3 3/4 inch scale running on 7 1/2 inch track 3 ft and 2 ft respectively). I will have pix on Friday. Russ