RE: Lionel-AF Big Boy
There appears to be some confusion (above) regarding this engine. The Big Boy was made using the K-Line 0-31 boiler, tender, trailing truck, and tender lead truck tooling. New non-articulated split two-motor running gear was tooled to run on S gauge track fitted with the Legacy and RS boards of the period (circa. 2009) along with an Electrocoupler(TM). S gauge wheels were fitted to the not-scale trailing truck and tender. Although the engine and tender are shorter than they should be, the principle sin (among several) as a model is the height of the engine and tender. As built, the model will negotiate Gilbert curves, but turnouts can be a significant struggle, particularly in reverse. In order to manufacture an all new, accurate UP Big Boy, almost everything except the scale-sized Challenger tender would need to be newly tooled ($!!). If one is interested in the details, I reviewed the Big Boy for the March/April 2010 issue of S Gaugian.
I own a sample that has the great benefit of the Carl Tuveson mods whereby both operation and appearance are much improved. As modified, it is a fun engine to run with the best quality sounds of any Lionel AF steam engine to date. Unfortunately, it is still over 2 scale ft. too tall, as well as over 4 ft. too short. Oh, well.
Have fun.
Bob
The L-AF Big Boy as delivered: