Hi Miles --
I've tried to analyze your goals, and they just don't leave me with an internally consistent picture of what you are trying to accomplish.
You want modern era, you want coal loading in the Powder River basin, and you want coal delivery, to have a loads in/empties out scheme. In addition, you want local switching of several plants. In H0 scale, in a normal sized bedroom.
First - I don't think the coal in/out thing will work very well on your layout, for two reasons:
1) The loads in/empties out scheme can work where there is quite a bit of run length between loading place and unloading place, relative to train lengths. But in H0 scale in a bedroom (as opposed to N scale in a basement), you just won't get much run length from point A to point B, especially taking into account problem no 2:
2) More importantly - six car trains just doesn't look anywhere near credible as a coal unit train that would require a flood loader. Unit coal trains in the Powder River basin are 110 car trains with 6-10 engines distributed throughout the train. You will not be able to create the impression "long coal unit train" with six H0 scale cars.
However, you might conceivably create the impression of long coal train with e.g. two engines and twenty Bethgon coal porters (prototype length 53 feet per car, 7.3" long in H0 scale, 4" long in N scale), for a total train length of about 8 feet in N scale or about 14 feet in H0 scale.
If you really want to create an impression of a coal loader in the Powder River basin, I would have gone to N scale, made a hidden staging yard of e.g. 4 curved 9-foot double ended staging tracks in a diamond pattern along two sides of your layout (e.g. top and right). To get loaded, the train departs in a counterclockwise direction, ducks out of hidden staging and immediately go under the flood loader (so you don't need both empty and loaded coal cars - they stay loaded all the time). After getting loaded, the train continues counterclockwise, and either ducks back into the other end of the hidden staging tracks immediately, or takes an inner loop to halt in a small yard of maybe two or three holding tracks in front of the hidden staging tracks and flood loader, while the next train is loaded at the flood loader.Then the first train departs counterclockwise on the eastbound track, crosses over the outer loop and heads into staging again.
A scheme like that would allow you to rotate five or six 20-car trains through your flood loader, and make an impressive display layout. You could possibly in your room take it up to 30 car N scale trains, which would be about 12-13 foot long, and which would look very long when they pull through the loader at slow speed.
If, on the other hand, you want to make a layout based on local switching of a small handful of industries in an industrial park or some such thing, in e.g. the HOG (Heart of Georgia) style Scott Perry advocated, then that is entirely doable in H0 scale.
Here is e.g. a rough start of such a layout, with staging for two trains of six 60-foot cars, and an ethanol plan in one corner - it would be easy enough to add two-three respectably sized industries along the top and left of the layout:
Basic idea is that the staging area is fiddled from outside the loop - you set up whatever trains you want to arrive during the session here. And then you duck into the loop and do your switching, before letting the outbound train head out again. A detector at the left end of the staging track tells you when your train has arrived in staging and should be stopped.
One possible job is switching the ethanol plant in the lower left hand corner with a dedicated plant switcher - pulling the hopper cars slowly forward to unload one and one car, swapping the emptied cars with three more loaded cars from the holding track/siding when the first three cars are emptied, and pulling the three loaded ethanol tank cars from the loading rack and spotting three empty cars there, so there is a cut of six cars (three empty covered hoppers and three loaded tank cars) on the siding which another train can come in and swap out with six new cars from staging (three loaded hoppers and three empty tank cars).
As in the N scale comments above, it would also be possible to have longer staging tracks along the top and left wall, behind buildings or behind a removable backdrop.
But local switching of industries in an industrial park is a pretty different concept from the unit coal trains going through a flood loader.
I guess the first order of the day is to think a little more about what style of railroading you want the most. Then you can think some more about how to accomplish that vision within the space you have available and within your chosen scale and era.
Smile,
Stein
