Comparing X12 with Big Boy

Perhaps some of you can help me:
1. I assume X12 is an articulated locomotive. In this drawing I see just an articulation between main locomotive and the cooling car.
2. Is it possible for head piece to be supported by three bogies? Should it be another articulation? Where? ahead control area? Between control area and the reactor?
3. What is the steam generator in control area? Is it the generator to heat the train (mentioned in text)?
Thank you in advance.