Casey,
There were two boxcars painted in the mid 60's for use on the Silverton Train. This one, #3768, and I believe the other was #3519. I'm not 100% sure on those numbers, I'm getting a little long in the tooth.
They were used to haul gear and baggage to the Ah Wilderness Ranch and also for hikers and campers who were let off along the way. After cars #126 and #212 were each fitted with concession supplies and equipment, and placed mid-train, the two boxcars were put in service as described.
When first painted in Aspen Gold, the two bocxars were lettered as pictured. By the end of the 60's, the lettering was spelled out across the length of the car in the same scrpit as the coach letterboards.