Other than the angle of the vertical tube, the rest still looks OK, so I guess there was some utility to using it with different angles as long as the bottom of the tube couldn't be seen.
Looks to me as if they were trying to hide the shadow the physical / "real" engine core element was casting "towards" Scotty.
Good thing they realized the engine core looked weird and instead went for the correct angle, where that shadow was noticable (but sill hard to see):
Please notice that the page excerpt (thanks Maurice
) refers to the whole thing as "engine core
". That's also what the screenplay said, so I shall use that term henceforth.
Since it powers both engines (i.e. impulse and
warp drive) that term makes a lot of sense where in contrast TNG's "warp core" was exclusively powering the warp drive.
Also, I never appreciated until some of the photos in this thread is that the room is asymmetrical and the starboard side much shallower than the port. I wonder if the idea was a turbolift shaft could run along that side. It also has a nice synergy with the original series engine room and it's asymmetric ceiling.
That was my first thought, too. I shall make of couple of graphic sketches to see how turbo lift transfer from the saucer into the engineering hull could work.