Dear Mark:
If you do decide to amend the plan, how about eliminating the space-hogging loops on each end and set up a true point to point? You could go back to the turntable at both ends plan which would serve two purposes: First, the turntables would act as a run-around for your engines so an engine could get to the "end" of the train front or rear. Secondly, if would provide you with the ability to turn any engine. Or, you could just having run-arounds--engine escapes).
Think about this: I'm a firm believer in the participation element of the design process. If you have a loop to loop continuous arrangement you can pretty much stand there and watch it. There isn't much of a run to begin with. That's not a knock. It's a fact of reality. If you set the Blackwater Canyon Line up as a railroad, like a real railroad, you will have to control the engine, couple and uncouple, start, stop...etc. switch out cars. Much more involvement! Much more fun! Much more interesting than being an observer.
I understand folks wanting a continuous option at times to just sit back and relax and watch. However, anyone could always set up a temporary loop of track on the floor and loop at heart's content. I would make my regular set up a model railroad instead of a display layout. That's just me. You have to decide.
I think you will discover in not too long of a time period you would be bored looping as most people are. You can achieve realism with a continuous run but have to be disciplined enough to not just circle without purpose. Our steamers stop at every water tank. And pick-up, drop-off cars at almost every siding. We only run a train from one "end" to the other "end" and that train's "trick" is complete for that night. Doing those things, keeps our crew busy and entertained for hours and that isn't an operating session. However, everybody has their own interest and opinion. This is your line. It is entirely up to you.
Since your space is limited. I believe that you should seriously consider making your line an actual model railroad instead of a display type layout. I wish that you were closer to us so you could experience operation in action. It is fun operating a layout like a board game or actual line and switch cars in and out, change engines, set up and break down trains etc. I've got several guys coming now who want to dismantle their loops as they see the fun and interaction that their current layouts are missing. One guy has a monster layout--wow--that's going to be an undertaking.
YOU ARE WELCOME HERE ANYTIME. While you are thinking about your layout, you could make a field trip out here to see the Glacier Line in Action. Of course, you would be doing it and not just watching. No one watches here! We operate; including the nice looking women!
REGARDLESS of what others say, including me, you take all the time you need to decide exactly what you want BEFORE you do anything! I think that was in my book, huh? This is NOT a race.
I'm your age. I can appreciate what you are saying about your knees and bending to crawl up through access holes. I think you'd be fine, but admit an ideal layout would be one where you could just walk up to ANY portion of the layout (within 30 inches) and easily reach it. But, you want to design something correctly on your first attempt, because we aren't getting younger and how many more layouts are you wanting to build? Think about the time, money and effort and strain on the knees it takes to build a layout. You do not want to rush, putting something up and then say: OH CRAP! WHAT HAVE I DONE?!
You've got more to think about. I'm going to be very interested in seeing what you finally decide. Wish I was closer to help you construct some L-Girder Bench-work because it is the ideal method for layout support. In your case, if you do just go around three walls and eliminate the space hog loops you could have a minimum of legs for your bench-work making it easy to work on your layout--run wiring--and/or have a hidden staging shelf(s) under it on each end to switch out cars. Great possibilities.
Peace to you! Happy Thanksgiving!
John
