This is more of a thought or discussion than a question. Almost all non-brass articulated steam locomotives have the nonprototypical two swivel driver sets, instead of the accurate front only. The only exception I can think of in plastic is the Mantua 2-6-6-2. The reasons I can think of are the curve radius , ease of construction and cost. But I really like the full boiler swing and more of the steam lines and other details that can be in place. Any thoughts from you guys?