Here the lone member of class S-1a, No. 6000, reposes briefly in the yards of the Cincinnati Union Terminal in this photo from my brother David's collection. It was taken in September 1954, but the photographer is unknown. The class S Niagaras were intended for fast passenger service and were designed to accept 79-inch drivers for this purpose. However the first example, No. 6000, was delivered with 75-inch drivers because of a wartime restriction on building new passenger locomotives. It had 25x32-inch cylinders and a boiler pressure of 290 pounds. The 25 engines of the S-1b class came shortly after the end of World War II and were built with the higher drivers. No. 6000 was so equipped, as shown here, in a subsequent shopping and her boiler pressure was reduced to 275 pounds to match that of the S-1b class. No. 6000 remained in service until early in 1956.