Bill: I am writing a book on snow fighting on the D&RGW and RGS. Several years ago, I was given copies of the D&RGW records of the 480s and 490s. Among the data listed, were the ones that were equipped with new snow plow pilots in the late 30s. I will include that list in the book. I also have a drawing of the plow pilots that includes a list of the engines they were applied to. There were smaller plow pilots used on the 470s in the late 20s and early 30s that proved to be ineffective and were replaced.