WARP CORE DEEP DIVE!
Where it all began. So much so, that they never quite nailed down what anything in engineering was. We know the thing in the middle was a "matter/antimatter integrator" and it had a dilithium crystal in it. But it didn't appear until later on, the floor was originally empty. There were also large transformer-ish things that moved about as the plot demanded. The big thing behind the mesh? That's the pipe cathedral. Maybe it was an impulse engine (as per the old Star Trek Blueprints by Franz Joseph) or perhaps it was part of the warp drive. Originally the idea was that the warp nacelles generated their own power. But that would change soon...
The Animated Series gave us something very similar to the TOS engine room, with the pipe cathedral and one BIG transformer, but instead of the matter/antimatter integrator we got a glass tube with what looked like measurements on it. Maybe it's a proto-warp core a la TMP, especially since it's in a similar spot to Strange New Worlds'. Or maybe it's a coolant pipe like the 2009 movie. Who knows? We also saw inside the "antimatter nacelle" in one episode, which is generally assumed to mean inside one of the warp engines themselves but it's all a bit vague.
The Motion Picture gave us the original Big Blue Lava Lamp, the physical set was 3 stories high but augmented with forced-perspective, in the form of a painting at the bottom of the shaft and a truncated horizontal intermix chamber crewed by children at the end of the main level. The engineering crew on the main deck now wear radiation suits, adding to the idea this big blue thing isn't your friend.
This was also the Big Retcon, making the intermix chamber the power source for the warp nacelles. Every Trek regardless of era would follow this route.
In Wrath of Khan, they'd add a very important side room with dilithium crystals in for Spock to self-sacrifice in. I always found it very amusing this room, where the most important part of the engineering machinery was, was in no way physically connected to the intermix chamber. Nor did it exist in the previous movie.
The Next Generation gave us a pot-bellied stove, with neon segments glowing one-by-one up and down to give the impression of pulses of energy colliding in the middle then being fed to the nacelles. No more radiation suits needed, and the room has a nice carpet. This was also the first time "warp core" was used, a phrase that would retroactively be applied to all the prior ones.
The Enterprise-E and DS9's Defiant would have bigger and smaller warp cores that were variations on the same theme as TNG.
Voyager brought back the classic Motion Picture big blue lava lamp, just without the horizontal tube this time. It does the nifty swirly thing too. Q Junior makes it do club lighting one time.
NX-01 Enterprise is just kind of this big industrial tank with some glowy bits. It's weird that in the classic movies they needed radiation suits to work in engineering, but in the series set 100 years earlier they didn't.
The 2009 reboot filmed engineering in a thinly disguised Budweiser brewery, which made the area look enourmous and extremely complex, but lost all the high tech clean room vibes prior shows had. What in real life were giant brewing tanks housed the intermix chambers which made up the warp core, which were ejected through a hatch in the roof at the end. This look was extremely controversial with some, but personally I loved it.
In Into Darkness the warp core looks like an almighty piece of kit, and that's because they shot on location at the Lawrence Livermore National Ignition Facility. It's a real-life fusion reactor. And then you can climb inside it and it turns out that inside is one very important laser thing, some dilithium crystals you barely see and lots of deadly radiation. At least the self sacrificing happens inside the core itself and not a weird separate side chamber this time. The brewery from the last movie was still there, implying this was all along even if we didn't visit it. But that complicates things because the bits they called the warp core are very different. Perhaps the intermix chambers ejected last movie and core seen here are all part of the same huge warp core system.
Strange New Worlds reboots the original... sort of. They put a vertical intermix chamber in there and instead of a mesh and forced perspective they've got an AR wall with an enourmous array of high tech pipes. But weirdly, the writers guide says the big AR wall with the updated pipe cathedral is the deflector dish machinery not the warp core. I guess the confusion makes it more authentic TOS.
