Okay, I guess the old saying that, "You can't see the forest for the trees," is true. In seeing the problem with the yard, I ignored the overall layout. I agree with Jim and although he did not say this I will and I hope you take it the right way-ditch the whole plan. If you are looking at switching operations in a space of this size, consider a transfer operation, that is, moving freight cars between two different railroads terminals in a moderate to large city. Transfer trains would run between two yards and the scenery would mostly be industrial, business and city scenes. This would work best with a fidder/staging yard to serve each railroad to run freight trains in and out of the scenes. But to be practical, you would have to use the entire wall around the room, with one wall devoted exclusively to the staging yard for each railroad.
You could also consider modeling one railroad's passenger and freight operations in this space using the aforementioned fiddle/staging yards to stage both passenger and freight trains on and off the visible parts of the layout.
Or consider modeling a fair sized yard and one major industry. Since you seem to be interested in coal operations, check out this site
http://members.tripod.com/appalachian_railroad/articles.html
There are a lot of good plans on this site for modeling coal operations.
Or what about a fair sized yard and one major industry such as a chemical plant that would use a lot of hoppers and tank cars or maybe a paper industry. You could also include some smaller industries for other freight car destinations.
Wyes take up a lot of space and I'm with Jim that yours is pretty much useless on your plan. Engine service facilities are great but don't use the space for one just because you think you have to have it. If you are not really interested in this (it's a part of operations like anything else), then stage the engine service facilities off line and use the space for something else.
I guess I seem to be rambling but not really. I'm just trying to impress upon you the need to sit down and think about what you really like, what you want in a model railroad, and not just to start laying track to be laying track. If you do the latter, the chances are good that you'll be tearing up track, probably sooner that later.
Ray