On the Fincantieri built ships I worked on, which I don't believe there is anything different or unusual about them from Carnival's, except maybe a little bit of the layout, the power system / propulsion system consisted of 5 Zulzer medium speed engines (12.6 MW each) as generators sets, producing 6600 vac. The engine and alternator were in the same compartment, located in two separate engine rooms (2 in aft er, 3 in fwd).
Power develop from one engine room went into one switchboard room (two main switchboards in two separate rooms). Each switchboard fed, primarily, the propulsion motors and hotel load, the propulsion motors were in another separate compartment. Each propulsion motor (~20MW) has two sets of windings; if you were to lose a component, you could still get half motor power. Plus each winding was driven by a separate switchboard - winding one of each propulsion motor - fwd switchboard, winding two - aft switchboard. Being a variable speed propulsion motors, each winding was driven by its own SCR driver (frequency drive) and its own propulsion transformer.
Like all propulsion systems, the controls would be from various WH locations, ECR, or in the ER (local). This is not an abnormal system from what I have seen and heard, it is a very common design with lots of redundancy built in. I found the system properly illustrated on SAM electronics website, attached below. To have a view of the engine room I describe above, head over to the video page, where you find two tours, one for Disney ship built in Italy, and one for the Royal Caribbean ship, built in France. The french built ones, had even more separation of compartment, but the power plant was nearly identical in scope and operation.
SAM Electronics has some good information on these systems. http://www.sam-electronics.de/dateien/pad/prop.html
The Disney ER Tour is here - http://www.dieselduck.ca/videos/01%20dd ... 20tour.wmv
The Royal Caribbean tour is here - http://www.dieselduck.ca/videos/01%20dd ... s%20er.wmv
More videos - http://www.dieselduck.ca/videos/index.html
To have two accident occur in short time frame, that disabled two passenger ships of this age and size is quite worrisome, due to the fact that passenger vessels now, are mostly identical in power plant package. To not issue proper accident report is extremely worrisome, as we may have major design issues, or operational vulnerabilities underlying both casualties (that we know of) that are not being addressed.