Re: 3 engine rooms in the TOS Enterprise's engineering hull?
"Either of these notions could explain why just one of these four ships seen on-screen would have a differently equipped Engine Room."
You are right and I stand corrected. Thanks for pointing that out, you are becoming the voice of reason when I get overboard with some ideas.
"The first duty of every Starfleet officer is to the truth, whether it's scientific truth or historical truth or personal truth! It is the guiding principle on which Starfleet is based! Jean-Luc Picard