I ran across this little gem today while going through some of my 770th R.O.B photos. The story as told to me (by Herb Crabtree, the machinist who took the photo) was that this was the result of a rear-ender in the fog...
According to Bruce Pryor's excellent website, this caboose started off life as D&RGW 0556 before going to the Silverton Northern. I assume she would have gone north in 1943, which is the same year she is listed as being wrecked. Apparently this was not the end however, as she became a car inspector shack (I assume somewhere other than Skagway?) before being burned in 1958.
Casey