@Wildstar - Yeah - the room does feel smaller in the render even though it is fairly matched up. One day I'll pick up the Worley plugin to do the camera matching if I get too frustrated
As far as I can tell, the pipes were just lifted up higher in later episodes exposing the third row of horizontal piping and the screen was not altered as Mytran indicated.
@Gagarin - I think you could get all the way to the shuttle area from the bridge as there was no implied turbolift changeover in "Let That Be Your Last Battlefield", IIRC. Also, the refit Enterprise could go from the cargo bay to the bridge apparently non-stop.
@Mytran and Albertese - Yep, I've tried with designer's intent but it just doesn't look right so I am switching to the tapered power pipes look going forward
Adding to the discussion of the pipes function and what is at the end of the pipes... I'm leaning that the end of the pipes in the "distance" is the reactor. The pipes might be a form of the future "linear intermix" conduit as seen in "The Motion Picture". Taking a look at this screenshot I could imagine this behind the TOS screen with the intermix pipe poking through it through the engine room