>>1429587From Drex Files:
A great view of the engineering staging bays. Mike and I always felt that the NX was a ship that took constant work to keep running. Tearing the warp engines down would have been a regular occurrence, and this area of the ship would have been buzzing with activity after nearly every sustained period of high warp travel. During WWII, my uncle was the engineering chief on a submarine. The old diesel subs had two engines. One was always being torn down, renewed and put back together. My vote would have been for two warp cores. One always in a state of rebuild.
The doors on the fan tail are dedicated engineering facilities, and are not cargo bays. The TOS style A-frame assembly conceals the engineering tunnel. When in drydock, the entire A-frame assembly can be removed, and the warp core, or even the entire engine room, could be slid out like a drawer and replaced. The idea being that while the NX is out there exploring the unknown, a new engineering department is being built and tested in an Earth orbital facility.