Removable roll away bridge between layout sections... Maybe a Double Helix..

[GaryHinshaw]

Rough calculations.. for the Helix.. (someone check my math)
1% grade
2.5" Rise per turn.
143.25" run == roughly 23" Radius (which oddly enough is the tightest main line radius on the layout... )

I'd need to rise up to 96" -- from 50-55" so about a 40-46" rise / 2.5" = 18.5 turns per helix
18.5 turns x 143.25" x 2 helixes x 2 main lines = a Crap ton of flex track....... 10600.5" / 12 = 883' of flex track..
Or.. 10600.5"/ 30" = 353.3 pieces of flex track...     Or about $1,750 in track.. .. plus the cost of the Helix itself..

I would encourage you to revisit the helix option, as I think you have made several worst-case assumptions here that make it seem much worse than it needs to be.  (Although you have one math error that makes your track estimate almost a factor of 2 too small.) 

My questions:

* Do you have a requirement to stick with a 1% maximum grade?  That is quite conservative. 
* Do you have a requirement to maintain 96" clearance?  A standard doorway is only 80".
* Can you have the lower elevation of the helix be 55", even if the rest of the benchwork is closer to 50"?

Let's consider a 2% grade and an elevation difference of 80-55=25" (instead of 1% and 46").  This requires 1250" (104') of run to achieve the elevation change vs. your 4600" (383').   At 40 smph, this requires just under 5 mins to climb the 25"/2% helix, so you're looking at a ~10 min transit of both helices, instead of ~35 min for the 46"/1% version.  That is not so bad.

In terms of total track, multiply the above lengths by 4 (2 helices x 2 tracks) for a total of 416' of track vs. 1532' of track.  That's a big difference!  Unfortunately, at MBK prices, you're still looking at ~$750 of flex (vs. $2770 for your 46"/1% scenario).

Note, there was one error in your math: a 2.5" rise per turn at 1% requires 250" of run, which is almost a 40" radius.  Your 50" to 96" rise at 1% requires almost twice as much track as you estimated...   

I'll be the first to admit that helices are not fun to build, and they're a pain when you have derailments in them, but they're not all bad.
-gfh

[GaryHinshaw]

Two more comments I forgot to mention:

* A 24" radius helix with a 2% grade rises 3" per turn.  If you use thin roadbed (I used 1/4" baltic birch ply in my Vortex - very happy with it), this gives you pretty good finger clearance to access wayward trains.  (You should count on spontaneous decouplings/runaway cars and/or derailments now and then.)

* On the subject of $$$, a layout this size is going to require a lot of it (amortized over years).  As rough numbers, I would guess you'll have about 400' of mainline run (equivalent to twice around the room perimeter), double this to cover sidings, industrial tracks, etc., and add roughly the same amount again in staging, so maybe 1200' of track.  At ~$2/ft you're up to $2400 for flex track.  Add ~100 turnouts at $20 ea for another $2000.  Then there are trains: you could easily count on having 50 locos and 500 cars on a layout this size (probably more).  If you are going DCC, this is maybe $150 per loco ($7500) and $15 per car for another $7500.  Pretty soon you're up to $20K or so just for the essentials (or $2-4K per year over 5-10 years).   Then there is benchwork, electronics, structures,....

If numbers like these give you, or your CFO, the heebie-jeebies, it's probably best to scale back now and develop a more modest plan for the lower half of the space - and leave hooks in place to expand across the gap as time/money/interest dictate.

Looking forward to following your progress!

[OldEastRR]

First Rule of Basement Layout Planning: avoid basements with solid concrete interior walls ....

Going up one tall helix then coming right down another one is going to put a big dead time into each train's running no matter what. I think the best part of model railroading is it's what big railroads do, WITHOUT the hours-long boredom of just driving the train from one "action scene" to another. However, I've found helices provide a very close duplication of this feature in N scale. 

The idea to make a simple unscenicked beam carrying two tracks, bolted into place only for operating sessions, is the best idea. It doesn't need to be there all the time. Sometimes your "railroading time" may only be working a yard or large industry, or even just changing CVs and addresses on a loco. No need for the entire layout to be continuous and fully operational then. Even for plain roundy-rounding, a quick bolt-up of the beam and you're set, take it down when done. Unless you've having an ops session the same time a tornado is bearing down and your family would like to get into the shelter, it should work out pretty well. 

[nkalanaga]

That's why I suggested setting the bridge on pins, rather than actual bolts.  In an emergency it could be lifted out without undoing anything, and its own weight would keep it on place while running. 

In a less sensitive location I agree that bolts would be a good idea, to keep someone from using it as a duckunder, ten standing up while the train is on it.  But in this case speed is an issue, and if it's built on a metal beam the weight will be enough to keep it steady.

[3DTrains]

Let's not forget maintenance. Assuming you're able to reach the point of completed track and a modest amount of scenery, expect to spend several days before running an op session (cleaning track, addressing turnout issues, finding the odd short circuit, etc.).

I have a fairly good open space available, and although I'm still planning (dreaming), each new idea gets closer to what I feel will be something I can handle. Triple deck, then double, around the room (all representing an entire division), and now I'm thinking a more enjoyable layout (for me) would be one that focuses on a small area (one or two towns) along two walls with one peninsula. Not only will it take less time to build (and at a more reasonable cost), but also take far less time to maintain. I can also be confident that I wont overcrowd the aisle space with operators/visitors, and that I may actually not mind the upkeep in anticipation for the next op session.

Don't get me wrong, I like big layouts, and in another life I may want a super-sized pike. In the end, however, I'm the one who has to build it and keep it running smoothly.

Anyway, that's my two-bits.

Cheers!
Marc - Riverside

[DKS]

For what it's worth, this is how I'd approach the situation.

First, I'd design the larger of the two layout halves (or perhaps even both halves) to be functionally independent, like two separate railroads. The connection between them then becomes a bridge line, logically and operationally. This way, if you wish to operate while it's down, you're not hamstrung by the missing piece.

Physically, I would build two fold-down bridge pieces, each of which is hinged near the wall. In the center is a simple interlocking part that keeps the two halves aligned and connected with a single pin. This way, it can be lowered and out of the way in a couple of seconds. Reconnecting them may take a little longer as you'd probably need to ensure everything is in alignment before sending trains across.

I'd likely make the folding bridge parts from extruded aluminum channel, such as shower door track or something equally rigid. The interlocking assembly may take a fair bit of work to fabricate, but you'd only have to do it once. I've rendered a simple sketch to show the principle of its operation. (The drawing is not to scale.)



Not shown in the sketch are short walls along both sides, perhaps made of Plexiglas, to keep derailed trains from making a fatal punge off the side.

[sirenwerks]

I like David K. Smith's idea. Caveats are that both side fold flush to the layout when not in use so they're not flapping in the wind and out there to be damaged and I'd actually make that center pin a rod of significant length, or at least height, and possibly light it like a real beacon. How many times do people go into the basement without turning the lights on? I know I make forays into the garage and don't hit the switch, and later wish I had.

[pdx1955]

For what it's worth, this is how I'd approach the situation.

First, I'd design the larger of the two layout halves (or perhaps even both halves) to be functionally independent, like two separate railroads. The connection between them then becomes a bridge line, logically and operationally. This way, if you wish to operate while it's down, you're not hamstrung by the missing piece.

Physically, I would build two fold-down bridge pieces, each of which is hinged near the wall. In the center is a simple interlocking part that keeps the two halves aligned and connected with a single pin. This way, it can be lowered and out of the way in a couple of seconds. Reconnecting them may take a little longer as you'd probably need to ensure everything is in alignment before sending trains across.

I'd likely make the folding bridge parts from extruded aluminum channel, such as shower door track or something equally rigid. The interlocking assembly may take a fair bit of work to fabricate, but you'd only have to do it once. I've rendered a simple sketch to show the principle of its operation. (The drawing is not to scale.)



Not shown in the sketch are short walls along both sides, perhaps made of Plexiglas, to keep derailed trains from making a fatal punge off the side.

While that would work to cross a standard or wider doorway, I think the gap to be spanned pretty long looking at the drawings (close to 10'?). That would require benchwork over 60" in height and may require two people to connect and disconnect. In addition, gravity will always be working to push it down so the chance of sagging is great over time with potential slop in the hinges, the mating areas, or in the pin interlock assembly.

The most simplest elegant solution is a bridge made from aluminum channel with pins that could easily be installed by one person, gravity will work for you holding it down, and you don't have any boring waits in helices (which get old really fast if the sceniced mainline is not of at least equivalent length).

[Lemosteam]

^^Which is why I suggested a hinged accordion style.  The long aluminum bridge seems most practical to me in the end and not unreasonable to remove.

If someone is worried about accidentally knocking it down, fence slide pins into the wall at each end could be used to prevent that, but that's just more operations to do in an emergency.

[DKS]

While that would work to cross a standard or wider doorway, I think the gap to be spanned pretty long looking at the drawings (close to 10'?). That would require benchwork over 60" in height and may require two people to connect and disconnect. In addition, gravity will always be working to push it down so the chance of sagging is great over time with potential slop in the hinges, the mating areas, or in the pin interlock assembly.

The most simplest elegant solution is a bridge made from aluminum channel with pins that could easily be installed by one person, gravity will work for you holding it down, and you don't have any boring waits in helices (which get old really fast if the sceniced mainline is not of at least equivalent length).

I do not believe the entire 10 foot span needs to be open; this is why I asked what clearances existed along the two walls. Only a span as wide as the normally-used walkway need be open, which I can't imagine would be much wider than, say, 8 feet, which means 4-foot spans, or 48-inch benchwork, tops. I also don't see why it would require two people to raise and lock it. A single 10-foot long removable span with pins on both ends, on the other hand, would be more likely to require two people to manage, not to mention awkward to store.

As for the hinges and other components, I know of modelers who have used hinged spans for many years with no issues; regular door hinges are unlikely to develop much slop. While it's true the locking mechanism in the middle might wear some over time, it's not like the thing would be used multimple times a day. I imagine it would only be up during operation and down at all other times. Given that it would ideally be made of extruded aluminum, it wouldn't have much of a load, either, so I doubt it would suffer much from the effects of gravity. But of course I could be wrong; I usually am.

[Lemosteam]

OP says wifie wants the opening 100% clear in the first sentence.

[learmoia]

OP says wifie wants the opening 100% clear in the first sentence.

I need to get caught up on reading.. but I do have about 2' on each side.

 After seeing the DKS plan, I was thinking about a vertically hinged  setup that folds lIke closet doors.. but that may be too flimsy as well..

When I get a chance, I'll post a few different design ideas I've been working on.


~Ian

[nkalanaga]

If you have the vertical space, a two leaf vertically hinged span would work.  Have it fold UP at the fixed end, with the hinge in the middle folding the outer end down.  Then add metal bars in top of the outer section which, when the bridge is in place, lay flat on top of the inner section, on either side of the track.  There wouldn't any downward bending stress on the center hinge, because the bars wouldn't allow it to sag past level.  All the hinge pin would do when it was down is keep the two pieces connected lengthwise.  Similar bars at the loose end would keep it at the right height there, and could be designed to fit into alignment bars or channels, meaning no pins or other locks needed.  Effectively, when lowered, you'd have a solid bar, hinged at one end, and sitting on the layout at the other.

You would need something to keep the fixed end from dropping too far, in case it was opened without holding the outer end.  That could be as simple as a piece of wood, sticking out of the benchwork under the hinged end.  The details would depend on exactly how it was hinged.

To keep it up, when open, it could be designed to go back past vertical a little ways, against a stop fastened to the ceiling, so there wouldn't be any latches to worry about.  To open it in a hurry, grab the outer end and lift/push it towards the fixed end.  The bridge would open and stay open on its own.

[DKS]

If you have the vertical space, a two leaf vertically hinged span would work.  Have it fold UP at the fixed end, with the hinge in the middle folding the outer end down.  Then add metal bars in top of the outer section which, when the bridge is in place, lay flat on top of the inner section, on either side of the track.  There wouldn't any downward bending stress on the center hinge, because the bars wouldn't allow it to sag past level.  All the hinge pin would do when it was down is keep the two pieces connected lengthwise.  Similar bars at the loose end would keep it at the right height there, and could be designed to fit into alignment bars or channels, meaning no pins or other locks needed.  Effectively, when lowered, you'd have a solid bar, hinged at one end, and sitting on the layout at the other.

You would need something to keep the fixed end from dropping too far, in case it was opened without holding the outer end.  That could be as simple as a piece of wood, sticking out of the benchwork under the hinged end.  The details would depend on exactly how it was hinged.

To keep it up, when open, it could be designed to go back past vertical a little ways, against a stop fastened to the ceiling, so there wouldn't be any latches to worry about.  To open it in a hurry, grab the outer end and lift/push it towards the fixed end.  The bridge would open and stay open on its own.

[peteski]

Man oh man, this is really getting complicated!    I agree with DKS.
The more movable joints there are, the more possible points of failure and/or misalignment. Plus the cost and complexity go up.

REMEMBER: the KISS principle.