I've just spent a hour looking for that issue you mentioned. You can do it on line at
[index.mrmag.com] (click link below). I have all the back issues of NG&SLG to the early '80's. I also was told yesterday that the train order signal was featured in the NG&SLG, but couldn't find it either.
And that's right, the picture is of RGS coach 254 which served as the Vance Junction Depot for practically the whole life of the RGS. According the the Ridgway Museum (note the correct spelling this time), they will not take ownership until they have a place for it.