Observations

I see some potential access issues in  few places.  On the first level, there's a long reach behind the Pocatello roundhouse into the corner, and that will also affect the middle level directly above it.  The top level turnback curves with their deep scenes could be a nightmare to build, maintain and scenic.  It may be worth shortening the main a bit to reduce depth.

As for scenic possibilities, the territory selected should work well for a multideck layout.  There is very little in the way of scenery extending far below the tracks, and I'm unaware of any very tall bridges on the line.  The UP line has most of its route either in relatively flat country (i.e. Pocatello almost to the Montana line, and the valley floors north of there), or at the bottoms of canyons (Beaver Creek Canyon is the best known).  For the most part, the scenery directly adjacent to the track isn't especially tall, which will help it fit within the vertically restricted space between decks.  There also aren't many large trees in most locales, but plenty of sagebrush, which will also ease the task of scenicking. 

Rob, Thanks for the quick

Rob, Thanks for the quick reply.

I realized there is a reach issue into the corner behind the turntable/roundhouse so my plan was to build the bench-work extension for these only after the lower and middle levels were completely finished in that corner.  The other thing is I will round off that corner background with a view block.

Thanks for noticing the reach issue on the upper return loop blob. I assume I will add a view block to reduce the max reach in that area like I did in the lower level return loop blob.  In the back of my mind I think I was considering making the background 'wall' behind the upper level return loop removable which would provide access from the 'outside' of the mushroom (albeit requiring a ladder/scaffold since it's 7ft off the floor from the outside). 

Keep the comments/replies coming.  I need all the help I can get!

I really like the concept

I really like the concept (including the deep scenes in the upper corners of the top level, which can be absolutely spectacular.  The only problem there is that the access in the upper right corner actually sits partially over the already problematic Pocatello roundhouse - and you know that any derailments are going to happen at the hardest to reach spot possible....

The other concern I'd have about the roundhouse is mostly aesthetic - it faces backwards for viewing roundhouse operations  One solution might be to leave off the back (nearest to aisle) wall, so people (and operators can see into the roundhouse and shorten the track lengths for the center stalls to improve the access to the corners.  That's kind of like building partial structure along the backdrop, but this would be along the "front drop".  It makes for a neat place to show off interior modeling skills although, while I've read about people doing it, I've never actually visited a layout where it's been done and wouldn't try it myself until I actually saw it done on someone else's layout.

One final thing you might think about on the upper level is that route into the return loop is lower than route into Butte.  If that's deliberately a way to make the line into the return loop quetly disappear, fine.  Because that's essentially what will happen.  If that wasn't the intent, you might want to realign that portion so the route into Butte is in the rear.

I think those problems are all manageable and correctable, given the great potential of the general flow....

Do you have your large steam locos?

Before you commit to a minimum radius, you should build an oval with the 32 inch minimum radius and see how a 4-8-8-4 looks going around that curve.  I don't know how one would work or look on a 32 inch radius.  If the 4-8-8-4 is plastic, they look fine on the modular club's layouts, but our minimum radius is 36 inches.  If you are running a brass 4-8-8-4, 36 inches will be way too small.  The last time someone put a brass Challenger on our layout, It had to run on the inside main and nothing could run on the outside main because the 36 inch radius was at least 10 inches too tight for it, and that was a Challenger, not a Big Boy!

Mike, Thanks for

Mike, Thanks for the thoughtful reply.

I agree that the aesthetics of the current turntable/roundhouse are not optimal not to mention the 'reach issues it creates).  I will work on the design and see what happens when I try to flip them.

For the upper return loop, the reason the mainline descends in the background is that it allowed me to increase the length of the return loop (and subsequently the return loop staging tracks).  The upper return loop staging track lengths are the 'controlling' limit of train length on the layout.

Doug

Russ, I have currently have

Russ,

I have currently have two Trix and and one Rivarossi Big Boys.  They are functional on my current layout with 24" minimum radius.  They don't look good at all, but they are functional. I will perform the experiment with a 32" radius curve to see how they look. This will be a good test for my Walthers UP HW Pullmann passenger cars.  They don't come close to being functional with a 24" radius.

I also currently have 2 Lionel UP Challengers, 5 Proto 2000 2-8-8-2, 2 BLI 2-6-6-4, and 2 BLI 4-6-4.  Ergo the need for a fictional railroad (Armadillo&Butte) that shares track rights with the UP.

Doug

Good idea, Doug.

It is relatively easy to want big steam and start layout out a track plan, but it is really cheap to buy a sheet of plywood and layout some test track to try different curve radii to see what looks right, what is an acceptable compromise and what won't work at all.  It is a lot less expensive to find out all of those answers before you commit to a layout.

I should be able to change

I should be able to change the minimum visible curve radius from 32" or 36" (40" might not fit) . I will give that a shot as well as performing the 'looks' experiment.  Thanks for the suggestions.

Per suggestions, I have made

Per suggestions, I have made the following changes to the design. See the linked images for these changes.

Lower level:

Flipped orientation of turntable/roundhouse
Added additional in/out service tracks to turntable
Removed left side lead track
Increased length of right side lead track
Increased mainline minimum radius from 32" to 36"
Increased radius of helix from 34" to 40"
Moved helix entrance from back to front

Middle Level:

Increased mainline minimum radius from 32" to 36"
Moved helix entrance from front to back

Upper Level:

Increased mainline minimum radius from 32" to 36"
Increased size of return loop blob (because the helix below grew from 34" to 40")
Increased the minimum radius of return loop staging tracks from 26.5" to 30"
Added additional return loop staging track (4 now)
Redid return loop staging tracks to equalize their lengths

http://www.onewolf.org/Files/PlanA-LowerLevel2.jpg
http://www.onewolf.org/Files/PlanA-MiddleLevel2.jpg
http://www.onewolf.org/Files/PlanA-UpperLevel2.jpg
 

Any and all comments/suggestions are appreciated.

Thanks, Doug