Not yet complete, but I wanted to see how the 'standby power unit' (or whatever it is) was looking. In keeping with the 'Season 4' concept, these are slightly modified from the originals (which are hard to find good reference shots of, at any rate); the biggest change I've made is opening up the backs of the units so the large tube is visible from either side.
I've also added something that looks more like controls to the apparent control
panel which was already there before, and because this is for "The Time Trap," I've added an opening alcove on the back where Kali, the female Klingon officer, can stash the micro-explosive which Kor hopes will destroy
Enterprise upon their exit from the 'pocket universe.'
EDIT: Following up on some of the discussion below, I've added additional details to the unit, and I think it just
might be done!

The control pad is now UV-mapped and has both diffuse and ambient maps to light up the buttons (sorry, it's all one material, so if anything has to change, it will take a new map of
all the buttons ... ). I've also cannibalized the faceplate of the FlatComm to add a display - it seemed an appropriate solution, given
Trek's history

. And, as I cogitated below, I supplanted additional greebling with panel breaks on the ends, to make it look more like something assembled and not just milled out of a solid piece of Engineerium ...
I love what you've done here. Only one major modification and frankly, I love how it opens up the device. (Of course, the original prop had a solid back (for "The Enemy Within") so it could hide the "evil" Kirk from immediate view.) I also like the subtle paneling you placed upon the side. They imply the inner hardware can be accessed.
One time as a visual experiment, I aligned 5 or 6 copies of XCalPro's version of this device in a tight row, almost no spacing between the "blocks" and applied a glowing "veiny" procedural to the "tube". Rendering it from a near floor level three-quarter view made the arrangement look like a TOS version of the horizontal power conduit featured in TMP. I don't know where within the "5 year mission" version of the ship such a structure could fit, but I thought it looked rather cool.
Sincerely,
Bill
I think this unit is actually the housing for the serial-linking hamster wheels.
The whole "anti-matter" think is all just a myth created to impress the Klingons.
I like that it looks like you have space between the units where you could possibly place a character for a shot. Pretty dramatic with two big glowing tubes-o-power on either side of your engineer's head...
As for the greebling, I don't plan to go any further than was already there in the show, but that means I still need to add a couple details on either end, and also another piece on the front 'apron.'
Funnily, I hadn't initially intended modeling these at all - I was just basing the space around XCalPro's excellent freebie units, but they were so long in combination that there was barely any room to walk around them at either end or in between (those sneaky production people apparently left out the front of the set when filming it with two of those in place!
Good idea about the couplings - I had thought about that, as well, but haven't gotten that far (similarly, I may do that with the big impulse manifolds behind the 'fence' ... )
I like that you put a station on this that can be manned. One of the challenges in creating illustrations set in Engineering (for TOS) is that there's only a few stations where you can show characters doing their job. Since those stations are set into walls, there's only so many angles for your shot. With a free-standing unit like this, it should be easier to set things up for the camera in an interesting way.