General layout shape - more curved or more straight sections?

If you are making the footprint of your oval helix 42 inches wide, you may want to consider building a slightly larger, 4x8 foot, 3-loop bowl-shaped oval helix instead of a stacked (cylindrical) helix.
A number of years ago, I developed an Excel spreadsheet for calculating dimensions of a bowl-shaped helix of any size, radius, grade or ramp/loop width and the supports that would go with it. It is stickied (pinned) at the top of the Layout Design Discussion forum home page.

I plugged the following variables into the calculator: 16 inch minimum radius (at the bottom of the helix...but it continually increases to 24 inches at the top); 2% grade; straight oval side = 48 inches; 2% grade begins 50 inches before entering the helix loop, and continues 2% grade for 50 inches after exiting top of helix; and 2.5 inch wide ramp/loop (for double track on 1.5 inch center lines).
The inside edge radius of the 2.5 inch wide ramp/loop would be 16 inches held for less than one inch and gradually increasing 2.5 inches each loop; inside edge radius at start of 2nd loop = 18.5 inches; inside edge radius of 3rd loop = 21 inches and outside edge at start of third loop would be 23.5 inches.

Two loops of your helix could be cut from one 4x8 sheet of OSB Panel, plywood, or Homasote in a single spiral cut and dropped cookie-cutter fashion onto stair-step supports. Because the outside edge of the curved portion of the top loop exceeds 48 inches, it will need to be cut (probably in 2 or 3 sections) from the long side of a 2nd 4x8 sheet.

A bowl-shaped helix nestled in the upper left corner of the plan posted today (Wednesday), would have a slightly bigger footprint than a stacked helix, but you will find the initial construction, routine maintenance, and any future repairs will be MUCH easier, because you will have total vertical access to the track when you stand inside the helix to build, maintain, or repair the tracks (meaning, there are no supports interrupting access, so you can vacuum or solder without being hampered by the next higher loop getting in your way). Additionally, by running the next highest loop outside of the lower loop, you are not forced into making a steep grade to achieve enough rise in a single loop to provide adequate clearance between lower loop railhead and underside of next higher loop.

Three loops of a 4.5x8 foot bowl shaped oval helix at 2% grade will yield about 13 inches of rise; and, if you start a 2% rise from the lower deck 50 inches before entering the helix, and continue a 2% rise for 50 inches onto the upper deck after exiting the helix, you can have 15 inches separating the surface of the upper deck from the surface of the lower deck. Judicious placement of viewblocks and daylighting 1/3 to 1/2 of the top loop will mean you only lose sight of the train for 2.6 loops, while gaining an easily viewed lower deck and lots more room for visible mainline and scenery/structures before parking your trains on easily accessed staging tracks. Some people complain about how long their trains are out of sight in helixes, but I point out that they will patiently wait 20 to 30 minutes between trains when railfanning, so they should view the 2 min:30 seconds wait for their train to reappear from the helix as a big improvement over 1:1 railfanning.

I have 4 single track, bowl-shaped helixes on my n-scale layout (3 circular, and 1 oval). (See my Albums in RailImages: Helix Pics or Layout Tour Pics )
My lower decks are at 48 or 53 inches and my upper decks are at 64 or 65 inches. On a previous layout, I had a double track stacked (cylindrical) helix between decks at 36 and 58 inches, but went with the 48 inch lower deck for my current layout, because access to the old helix was only by crawling on hands and knees and contorting myself into the 28-29 inch inside diameter helix. All current helixes are accessed by duck walking or sitting on a wheeled dentist's stool, bending over, and comfortably rolling my seat into the helix (still only 28 to 29 inch inside diameter at 48 inches, but the bowl shape leaves much more shoulder room than the cylindrical helix--48 to 54 inch inside diameter at 64 or 65 inches--and the underside of lower deck supports are at 42.5 inches instead of 31).

You may already be considering this, but...for what it's worth. On my current layout, the original plan was to have plain/undecorated staging on the lower level feeding modeled/detailed cities on the upper deck, but that idea quickly morphed into providing scenery and structures on the lower level, as well. You may end up wanting your lower shelves to have scenery, too. Plan ahead where your upper and lower level work areas will be located, so someone working on one level is not blocking someone from working on the other level. If upper and lower work areas can't be staggered along the aisle (AND ACROSS the 36 inch aisles, too!!), then at least have provisions for working one level a step or two to the left and working the other level a step or two to the right, so operators aren't getting in each other's way.
FWIW#2: My lower level shelves range from 18 to 36 inches deep (maximum reach to mainline track = now about 30 inches in a corner). Even after moving those corner tracks from a 32 and 34 inch reach down to a 28 and 30 inch reach, that's still too far and cramped between decks for me to reach in and work comfortably for more than 30 seconds...and I've got a larger separation between decks than you have proposed. So, I would strongly urge you to keep tracks in the lower level Expansion Area no deeper than under the middle of the upper deck (e.g., 20 inch deep upper deck, all lower deck tracks at least 10 inches from backdrop.

Separation between decks, elevation of both decks, depth of the upper deck, thickness of the upper deck, width of the aisle, height of the operator's eyes...any of these factors considered individually, can significantly influence how far you can see into the lower or upper deck. And there is also a dynamic interaction between them, as well. You mentioned experimenting with heights and separations of decks, have you also considered thickness of the upper deck and how that interacts with the depth of the upper deck to affect how far you can see into the lower level? Also, have you tested whether lights or light fixtures suspended from the underside of the upper deck will be hidden by the bottom edge of the upper deck fascia? (Sigh. Yeah, that's the Voice of Experience asking. I found out the hard way that moving the light fixture back from the fascia hid more of the fixture than when it was closer to the aisle, but I ended up having shadows on the fronts on my rolling stock because the lower deck trains were closer to the aisle than the light fixtures.)

 

Followed the link to your blog/website...Very Nice!!!
One of the pics shows a lower level support/brace (about 31" above floor??) going diagonally across the corner where the electrical panel is located. It looks like the electrical panel might be hard to access, if you have similar diagonal supports/braces for your middle shelf at 45" and upper shelf at 59", especially if the lower edge of the panel is less than 59". Or do you already have different plans for the middle and upper decks in that corner?
A friend of mine handled this same issue on his layout (deck passing in front of an outlet and an electrical panel) by painting his walls and the panel door with white and gray clouds. Your panel obviously has a much nicer finished look and might almost disappear completely with a similar treatment.

Jim C. 2014-09-14 15.29.59 by ppuinn posted Dec 22, 2017 at 9:45 AM

Jim C. 2014-09-14 15.28.10 by ppuinn posted Dec 22, 2017 at 9:45 AM

 

Your most recent plan has the long axis of the oval going north-south. Does window access or aisle width to the peninsula prevent you from shortening the west side of the oval to 16 inches and making the helix a 3-4-5 triangle with straight sides of 16, 21.33, and 26.67 inches, or a right isosceles triangle with sides of 16, 16, and 22.63 inches? If my rough calculations are correct, you might need to shorten the peninsula by a few inches (maybe one car length?) and/or shave one inch off the depth of the bulge on the helix or the shelf to the right of the window to help you maintain at least a 33 inch choke point between helix tracks and peninsula for the 3-4-5 triangle, but I think the right isosceles can fit without major changes.

Your recent staging level plan shows the eastbound trains will go to the support column shelf, cross the 30 inch gap, enter the helix and go up to the upper deck. The middle level plan shows a turnback loop at the end of the support column shelf (no bridge over the 30 inch gap to get to the helix). Does the turnback loop go into a second helix and up to the upper level support column shelf? Or, does the train go back through the middle level towns again to get to the oval helix to go from the middle level up to the upper level? Or, do you plan to have a bridge at the middle level, too, so you can cross the gap and go into the helix to get to the upper level. Such a middle level bridge would allow you to avoid passing back and forth through the same scenery (or spending long minutes getting back to the helix on hidden track behind your middle level scenery), and it would preserve your east-is-right/west-is-left travel on all levels. Additionally, it would mean you only have to construct one helix, instead of a second one to get from the middle level support column shelf to the upper level support column shelf.
If you add a third bridge on the upper deck, you could access the helix back down to the staging level to complete a grand loop of the entire layout. Or you could just terminate at the top by going into a nicely detailed yard with scenery and buildings, or leave LDE 5 to loop around into staging on the door side of the upper level support column shelf.

 

Trainzluvr N 15x22 20171222 Dec 22, 9 23 12 PM by ppuinn posted Dec 22, 2017 at 9:41 PM

I think the 3-4-5- triangle will necessitate too many compromises, so this sketch of the right isosceles helix is the only one I've drawn. I drew the bottom of the helix on the lower level (no bulge), and as if you were going to have industries for switching on that level instead of only staging on the sides of the peninsula. You could also elect to put a bridge across to the support column lower level shelf, as in one of your earlier plans (but, as you've mentioned, that might complicate/interrupt operations on the outside of the support column shelves).

When positioning the helix and peninsula, I tried to be conservative about the room measurements...you may want to correct some of my numbers when you translate my drawing into a digital track plan. Note that the peninsula track (in brown) is 20 inch radius, the peninsula fascia (in green) is 24 inch radius, and the helix-peninsula choke point is 36 inches. If you want a 4 inch wide helix bulge on the middle level (or half way between the middle and upper levels), you could "borrow" a little from the 4 inches between the fascia and track at the choke point to maintain your 35-36 inch choke point. I also left 3 inches between the outer track centerline and the wall...you may want to have more (or less) in your final plan.
I put in several track elevations (circled numbers) and guess-timated the elevations in the helix for a 2% grade. If you want to move ahead with this plan or a variation of it, we can figure out the exact numbers relatively easily. The dotted lines in the helix represent centerlines of upper loops directly above the bottom level loop...so you can see the helix footprint.

I like the idea of having a nod-under bridge on the upper deck. My layout spreads throughout my basement and there are several places where I have 62 inch nod-unders. At 5'8", I can cruise under my upper deck pretty easily, but on your layout, you may want to add a loop to the helix and make a turnback loop to the outside of the support column upper shelf to climb a couple inches as you approach the door, and then pop through the backdrop (like the track pops through from Lockport on the lower level) and then keep climbing along the inside of the support column upper shelf a few more inches as it approaches the bridge/nod-under to the helix.

 

You mentioned that some operators may not be as tall as you, so working the upper deck at 59 inches may not be easy for them.
Most of the upper decks of my N-scale layout are 65 inches high. The lower decks are 48 or 53 inches high. To access the upper decks, I've built a number of 12 inch high benches. When standing on a bench, the upper level is functionally 53 inches high. When operators are working the lower deck, the benches are pushed under the benchwork and operators stand directly on the floor.

Under Layout Storage, East Peoria 2015-11-04 18.12.01 by ppuinn posted Nov 5, 2015 at 8:15 AM

2016-02-07 20.36.56 by ppuinn posted Feb 8, 2016 at 12:03 AM

Fascia Boards by ppuinn posted Jan 30, 2014 at 11:12 PM

In the distance of the picture below, there is a 62 inch nod-under to a narrow aisle with a raised floor. The yellow tape on the floor is directly under the front edge of all nod-unders as a caution to operators. The boards and fascia panels of all nod-unders have pipe insulation foam taped to them to protect operators from headaches. Notice, too, the foam insulation taped to the upper deck on the right protecting the nod-under to the dispatcher's desk.

BN Galesburg showing Benches by ppuinn posted Mar 4, 2014 at 9:57 PM

The picture below shows Wesley Jct, which passes through a doorway at 65 inches (completely filling the 32 inch doorway from 62 to 65 inches). It is also possible to see the 8 inch wide lower deck where it passes through the door and bends toward the left. The picture is taken standing on 12 inch high benches that can be rolled under the benchwork when operators need to work on the lower deck.

Wesley Jct by ppuinn posted Apr 20, 2007 at 9:58 PM

A few years ago, I built an HO switching layout at 30 inches. One end of the HO benchwork is under the 65 inch high upper deck where there is no lower deck at 48 or 53 inches, and the other end is under the 48 inch lower deck. Operators sit on a wheeled stool to work the HO switching layout. When N-scale operators are working above the HO layout, the stool is pushed under the HO benchwork to clear the aisle for working the 48 inch deck, and the 12 inch benches are pulled out to gain access to the 65 inch upper deck. The doorway filled with Wesley Jct mentioned above is just to the left of this picture

East End of Switching layout 2015-08-12 18.08.32 by ppuinn posted Aug 12, 2015 at 11:54 PM

 

The drop ceiling of my 35x35 foot basement is 7'5" except for 2 enclosed beams/ductwork that divide the space into thirds running from front to back of the house that are 6'8" and a connecting bar (forming a letter H) for ductwork...also 6'8". The step-up benches under the H bar connecting ductwork are only 10 inches high, so I don't hit my head (but several of my taller friends don't work the BN Peoria Yard Switcher Job or the BN Alley Job [which are both located directly beneath the H bar connecting ductwork], because the ceiling is too low for them). There is also a 4'4" x 35' fruit cellar directly under the front porch that runs across the front of the house, which I've converted to train space, too. That floor is between 3 and 4 inches higher than the basement floor, but there is no drop ceiling, so that ceiling is 7'6".

I'm familiar with 4 layouts here in Central Illinois (2 in HO, 2 in N-scale) that have very reliable lift-up (3) or drop-down (1) bridges. The bridges are set in place during operations, and are only raised/lowered out of the way when an op session is finished. If such a bridge on your layout remained in place throughout an operating session, then you would have to forego using the outside of the lower, middle, or upper shelves by the support columns for staging.

Flash Blackman, a Trainboard staff member, has a swing gate on his layout. It operates like the lower section of a Dutch Door.


Raising and lowering a plank with track on it and a single hinge seems more vulnerable to unreliability than than swinging a plank (bridge) with 2 hinges open and closed, but your construction skills and experiences may bring you to a different conclusion than my poor skills have brought me to.

Using bridges to span the gap from helix to support column shelves or vice versa on one, two, or all 3 levels has the potential of providing a very long main line run; east and west can be right and left, respectively, on 2 or 3 levels; and depending on where staging is located, an operator can progress over the entire layout without going through the same scene twice. Additionally, if you use an elevated track at the back of the middle and upper decks, you can have a mainline and branch line that are both about the same length.
The downside: Initial construction tends to be more complex and long-term reliability tends to be less for lift out, drop down, or swing out bridges than for track laid on a shelf. And using the outside portion of the support column shelves is interrupted by having to remove and then replace the bridge every time an operator enters or leaves that outside area of any deck level.

 

Depending on how many trains you have coming from Lockport (or staging or interchange/jct on any level), one person could be responsible for properly blocking the cars for easiest switching as the train is built, hostling the power from engine yard to head of train, having a caboose or FRED on the end of the train, having a throttle (with consisted power already keyed into it), and having the train parked/idling with lights and sound on and ready to depart around the column curve as soon as the crew accepts the clipboard/switchlist/car cards/track warrants/dispatcher's okay/Mother-may-I, or whatever authorization to go that is appropriate for your operating session. The hostler then begins (or continues) to break down any recently arrived trains on any level on the outside of the support column and builds the next trains that will be departing from outside the support column back to the "inside" of the layout.
Assuming you had staging outside the support columns on 3 levels instead of on either side of the peninsula, and further, that there were 6 trains arriving and 6 trains departing from the 3 levels (2 arriving/2 departing on each level) over the course of a 2 hour op session (1 train arriving about every 20 minutes, and 1 train departing every 20 minutes with 10 minutes separating each arrival/departure), the hostler would definitely be busy. The job could be made easiest, if most trains only have to be run through a reversing loop to be ready to return the other direction; lightly challenging, if engines and caboose/FRED need to be swapped end for end in order for the train to return to the other end of the line; tough, if cars from an arriving train must be broken into 2 blocks and used to build 2 different trains--one that will depart later in this op session, and one that will depart early in the next op session; and hair-pulling, crazy-making, super-challenging, if each car had to be individually assigned to and then moved to 2 different trains (like with a computerized switchlist or car cards) instead of moving a whole block at a time (all cars in the front half to one train, all cars in the back half to the 2nd train). If one level has 4 trains arriving/departing, a second has only 2, and the 3rd has none, then the hostler's job could be hair-pulling, crazy-making, super-challenging, if arriving cars must be individually assigned and moved to one of 3 different trains. Unit trains or passenger trains that only need to be turned and/or loads swapped in or out, will be easier to prep for a return trip.

Regarding peninsula staging...My thinking about staging changed rather quickly and dramatically as soon as I started using it.
The original plan for my current layout had only staging on the lower level...no scenery; and I deliberately put staging yards for the different trains as close as possible to the helixes where they left the upper deck. But that grew old VERY quickly (actually, the first time I ran 3 trains one-immediately-after-the-other), because trains were spending more time off the sceniced portion of the layout in the helixes or on the staging level than on the sceniced upper deck. So I started putting scenery on the lower level, and started reconfiguring the staging yards to more resemble the yards of their respective destinations. This was a LOT more entertaining for me (...although, it did produce some interesting juxtapositioning of modeled MidWest cities whose prototypes were actually hundreds of miles apart from each other: the Northern Division towns of Galesburg Illinois, Decker Montana, and Terre Haute Indiana are side-by-side each other [front, middle, and back of a 30 inch deep x 17 foot long shelf] and all 3 abutt one side of the Southern Division's Havana Illinois). As scenery increased on the lower level, I started adding interchange and switching opportunities too, which resulted in even longer and more interesting runs as I repositioned the staging towns to maximize length of run instead of minimizing it, and also to produce more chances to interchange cars. Eventually, by making the lower level a closed loop with scenery instead of 3 dead ends, I was able to double or triple the length of my runs, and still never go through the same scenery twice.
I know the opening/closing interruptions of any bridge activity are a significant concern for you, so closing the loop on the lower and middle level is unlikely. And, going through the same scenery eastward and then westward is a sour necessity that can be somewhat sweetened by using elevation to separate the eastbound track from the westbound track. You may already be planning something like this, but FWIW, some modelers foster or enhance a sense of physical separation (front/back, elevation high vs low) between two tracks by also using:
1. contrasting colors for the two tracks (greens and blues for one; reds, browns, yellows for the other)
2. bold vs pastels
3. bright/light vs somber/dark
4. texture: trees/shrubbery vs grass; paved/smooth vs bumpy (or rocky)/rough
5. urban vs rural
6. dry/sandy/desert vs wet/rocky (or muddy)/forest
7. prairie vs hills vs mountains
8. super detailed/lots of busy-ness (or action) vs plain (undetailed)/boring (dull or static)
9. view blocks (hills, trees, structures) between the areas, or hiding one area but not the other
10. distractors (nicely scenicked rivers, bright red car or building, or colorful billboard or unusual/interesting structure) to draw the eye away from noticing the two tracks.

We can also increase the sense of traveling greater distances by having the trains disappear from sight more often, never letting the whole train be visible at one time, and by minimizing the number of feet of both tracks that are both visible in the same scene.
And by running our trains at actual scale speeds...which are usually MUCH slower than we actually run our trains.

If staging is on the peninsula, what will be on the lower level shelf by the helix (yard? industries? minimal scenery?) or on the lower shelf inside the support columns (across the aisle from the peninsula)?

Will trains on the upper level also be going one direction at the front of the shelf and back toward the helix at the back of the shelf...or just the on the Middle level?

 

I'm a retired school psychologist, and when I was working, we used variations on SWOT analyses in the school districts when revising existing programs or developing new programs. When model railroaders are revising or expanding an existing layout or building a new one, they sometimes struggle juggling a host of variables...and, like a SWOT analysis, establishing the "Givens and Druthers" for a layout will often help modelers clarify what it is they want, establish priorities, and then plan how they can get from Point A (what they currently have) to Point B (what they would like their layout to be).

Givens are the factors that are relatively fixed (room size, ceiling height, window/door/column placement); elements that are unlikely to change in the next few months (modeler's height/reach, mobility); things that you definitely want to incorporate in your layout design (so far, you have steadfastly included a helix and staging in your designs, and you seem set on your scale, minimum radius, and maximum grade in a helix). Givens are factors you consider to be the very highest priorities for your layout.
Druthers are those things you would like to [you would rather...you'd rather...you "druther"] include in your layout design, but they are a lower priority than your Givens. 3 decks are ideal, but only 2 decks (lower and middle) will be good enough "for now". Scenery on the lower deck is a lower priority than on the middle or upper decks...but might be welcomed, if it makes a train's run seem longer, or if lower deck scenery let you include some signature feature of a specific RR you want to model. Avoiding lower and middle deck bridges is a higher priority than maintaining "East is right, West is left".

When you've established your Givens and prioritized your Druthers, it becomes much easier to make choices about what to include or not include in your layout planning. Obviously, priorities evolve as our knowledge, skills, or resources change, but then we update our Givens and Druthers, and the process continues.

 

Several times, you have come back to the idea of positioning staging on the peninsula on the lower level. Trains will leave the east or west yard, go up the helix to the middle level, East at the front of the upper level, cross right to left at the back of the 2nd level, up the helix to thee upper level, East across the upper deck, back to the helix over the Nod-Under Bridge, down the helix to the lower deck and then to staging on the lower level peninsula.

What do you think of this variation: Suppose you had a staging area on the outside of the lower level support column shelf (e.g., Lockport). Trains depart west and cross the lower level (which would have scenery, towns, and rail-served industries), climb the helix to the second level, travel east at the front of the shelf to a town (Middleton) on the middle level located on the outside of the support column shelf, pass through that town and return on the elevated track at the back of the middle shelf, go up the helix to the upper level, across the upper level and terminate in a 4 or 5 track yard in a town (Summit) on the outside of the support column shelf. Another train would make the trip from this town down to the lower level staging. A third and fourth train could cover the same route as westbound and eastbound road switchers instead of non-stop manifest freight trains.

As an alternative, a branchline could begin at a jct or interchange in Middleton, then follow the elevated route west to the helix, up the helix and exit to cross the Nod-Under Bridge into Summit, then take an elevated route across the back of the upper deck to the helix (comparable to the elevated route on the middle level), and then down the helix to the lower level, cross the lower level eastward to terminate in a town on the peninsula (South Point). This job would be a way freight stopping at every opportunity to switch cars. The return from South Point to Middleton could be made as the 2nd leg of a turn, or as a second (separate) job, independent of the first. If the upper deck is too shallow to provide adequate separation between the front and back routes across the shelf, then perhaps the mainline through the upper deck could be a double track main but only trailing point spurs could be served (so an operator switches half of the industries when running the westbound job and the other half when running the eastbound job).

 

Thanks for the AnyRail link. I'll probably download/install on Monday.