You have the parts identified correctly.
@Raven87 posted:Is there any source where a novice like me can learn about the internal electronics (and how they work/what they do) of these locomotives? I really dislike feeling so ignorant!
Sadly, it's the same as many other endeavors, it's a gradual learning process. OJT is the way a lot of us learned initially. Once you're been around the block a few times, you start to understand more about the internals. The TMCC models are fairly simple for the most part, some of the more sophisticated Legacy models get a little more convoluted. Then there's the whole MTH DCS side of the fence...
There are wiring diagrams for "Typical" models. For your Allegheny, the "Typical 2-6-6-4 Articulated Steam, Non-Odyssey)" would be fairly close, and will certainly give you an idea of the internal wiring. It's in this: Lionel TMCC Representative Locomotive Schematics.pdf file.
