493's screamer was very briefly on 476 when the D&S went into business in May 1981. It was a whistle that very much got your attention.
It was a standard D&RGW cast step top five-chime, but it had internal flaws caused by a shifted core in the casting process that left a couple of holes between the chambers and some other defects.
There was a whistle in Chama that had the same defects. It was on 484 in the mid-late-1970's It had a rather high pitched squawk-y sound. It was found to have a hole between the longest chamber and the center cavity. Somebody actually cut the whistle open and performed surgery to close the void. The whistle then became a standard-sounding 5-chime, losing its unique qualities.