Sorry to be so long in getting back to you folks. We had company over for dinner this evening, and they just left.
Many, many thanks to each of you for your well-thought out suggestions, and thank you, Tyson, for your welcoming comments. I feel very much at home.
Gary, in answer to a fundamental question, yes, I did forget to tell you that the "top" edge is against a wall. BDC, I think that failure may have led you down the garden path, as what I think you were trying to do was to create a two-sided layout with a scenery divider between the two. That would have been a great idea, but obviously it won't work in this case. Or did I misunderstand what you were getting at?
Putting the turntable in was almost an afterthought. It wasn't in the original plan, but since I had already purchased one (the Atlas unit with a motor drive) I thought I might just as well use it. It didn't occur to me that, while I went to great pains to build the wye so I could turn power at one end of the line, I had no way to turn it back at the yard.
Now, I agree that diesels CAN run either long hood forward or short hood forward. However (and I've never been in the cab of one, but I'd bet a nickel on this), I'll bet the placement of the controls makes short hood forward running much more comfortable for the engineer. Consequently, it seems to me that being able to turn the engines at BOTH ends of the line makes sense if it fits. I'm thinking of trying to rework the yard, angling it a bit so the interchange goes off the "top" side, and giving me access from the "bottom" side to either another wye or, as Gary originally suggested and Phil supported, by going under the loop to the turntable in the middle of the left loop. I think I would rather do another wye, but as has been pointed out, it would take a lot of expensive real estate.
OTOH, if I just stop worrying about coddling the engineers, as Tyson suggests, I could clean out a lot of track that is only used for turning 'em around.
What is the group's opinion, should I do away with both the turntable and the wye? If I did, I don't think I would like the layout to remain quite as sparse as Tyson drew it, but I should be able to use the space for more industry-switching trackage.
Gary, by the way I tried a search of the track planning forum for the active thread you mentioned which discusses the pros and cons of point to point vs. continuous running, but could not find it. If you can direct me to it I would appreciate it.
Not yet having read that thread, I think of a railroad as not going around in circles, but as going from one place to another. I visualize mine as a branch line serving a relatively small number of industries, bringing freight from the world (the interchange) and delivering it to those few industries, then taking their goods back to the world (the interchange). On my small railroad I see this as involving relatively short trains of six to eight cars, with MAYBE one freight going while one is returning, and one fellow is being kept busy in the yard.
You might wonder why I incorporated three passing sidings when, under this type of operation two of them would be unnecessary. I didn't actually think of them so much as passing sidings, but as runarounds to facilitate switching the several industries scattered along the way. I would appreciate your thoughts on that. How necessary are runarounds, or rather, in the scenario I described for my railroad, how necessary would they be?
By the way, Phil, you make a good point about the little siding just inside the back of the right loop. There really isn't room to put anything worthwhile there, so I will discard that one.
Tyson, you, too, make a very good point about the reach required to deal with that double track along the back of the layout. Color it "gone".
Despite my fairly strong feelings that I will want to operate point-to-point most of the time, I do see merit in what several of you have said regarding occasionally just wanting to watch things run or, of more practical value, breaking in new equipment. For that reason I will probably connect the upper end of the "left" loop with the track above it so I can run continuously if the occasion calls for it. Thanks, all, for making that point so clearly.
Billk, thanks for noticing that there are no tracks parallel with the long edges of the layout. Those drive me nuts, and I went to great pains to avoid them. I know they use space most efficiently, but they just don't look natural to me.
If it enters into consideration at all, the railroad will be DCC with, at most, two operators, although at first it will be only myself operating it.
One more time, let me thank you all for your help! It has been great and has caused me to re-think many of my design features.