Re: RGS #20 update - Domes

Actually, Everett, it is a difference in Suppliers. Remember, everyting that Baldwin did was to the lowest bidder, even on large productons runs. They were one of the first to use the competitive bid process on a large scale. You can find minor differences on all sorts of different locomotives of the same class from Baldwin. Johns Hopkins has an excellent history covering this.
Back to the Domes, however. New and Replacement Sand and Steam domes were available from different suppliers, including Westinghouse and New York Air Brake companies. The Rounded domes on C&S 71 have the familiar "NY" cast into their underside. It may simply have been that a single cast dome cost less than a 3 piece model that would do the same thing and was substituted mid-run. (obviously). Also, domes and dome heights were not ordered as a complete package. The simple Base and cap domes (without the extra rings) were ordered as just that. Only a base, cap and cover. The side of the sand and steam dome were nothing more than rolled sheet metal and had nothing to do with the base and caps other than fitting inside them. This is why you'll see sand domes with the same base and cap diameter vary in height from railroad to railroad and locomotive to locomotive.
See? You learned something today.
Rick Steele