Not to go too far off topic on this thread, but I'd like to make one comment about the Articulated locomotive found for research.  Although the Big Boy picture is photoshopped, here is a picture of the ultra rare 4-8-8-8-4 Virginian/Erie "Triplex" class locomotive.  There were only a handful of these monstrosities made, and usually had a wheel configuration of 2-10-10-2 and 2-8-8-8-2.  I learned of this mother in my encyclopedia on North American Steam locomotives.  This was built for the Virginian Line back in the 1910's IIRC, and they ran only for a few decades on this line and other major coal haulers like the Norfolk & Western and Erie.  Very unsuccessful locomotives due to their extreme maintenance and fuel consumption.

mdb