Seeking opinions on this layout plan: Appalachian Mountain River Town - Updated 10/26/2022

Now to build it, that's a lot more work than planning it.

Based on my experience of Appalachia in eastern West Virginia -

The entire economy during that era was getting coal out of the mountains.  Everyone was a coal miner.  When coal dried up, Appalachia dried up.

Mountains everywhere.  The concept of a small town next to a train line and a river is very sound.  The train would often follow the river and cross the river in/near a town.  Coal was in abundance.  Water from the river was necessary for the locomotives.  Your steep grades are at least prototypical.  Tight turns and unprotected crossings would also be prototypical.

Listen to "The Wreck of the Old 97".  I believe that was an express mail train trying to make up time hauling through difficult terrain in Virginia.  It wrecked at the bottom of the grade right before the trestle over the river.

The roads also snake through the mountains with many blind curves.  Everybody has a pickup truck.

The town would have nicer buildings all clumped together along the main street.  Many people would live off the land in shacks in the woods doing hunting, odd jobs, moonshine, gardens, etc.

I don't think you would see a lot of fancy railroad stuff in small town appalachia.  Engine yards and stations and such would be found in a (if you call it that) city.

I'd sign my name here, but it is the same as another member of the forum and causes much confusion.

As long as steam is running, most branches would have at least a water tower, maybe 2.    A small town on a mainline might have a water tower.     And if this is the bottom of a grade, a small enginer terminal would be very common as long as helpers are still needed to get out of the valley.     Think of all towns along the C&O through Va and WVA.  

It does seem like a lot of track in that space, however.

I should have said that this layout is meant to represent only part of a hypothetical town in the Blue Ridge Mountains of Southwest Virginia where I grew up.  I can think of numerous examples from which I have drawn inspiration for this design: Galax, Clifton Forge, Covington, etc.  During the transitional Era, they definitely had track side Water Towers for refilling tenders and lots of Coal traffic.  Many also had industries for timber, agricultural, crushed stone, lime, and cement products.  Some also had manufacturing that used these raw materials to make building and consumer products.  But these points are an aside to the point of my request for suggestions about the track plan, and only mentioned to give the layout context for the proposed terrain.

The ultimate goal for making this layout is to maximize the play value, not so much recreating a truly prototypical single town. I have no questions about what industries (buildings and accessories) to include.

The types of suggestions I am primarily seeking would be for maybe reducing the steeper subterranean grades and still taking full advantage of the available space and track I already have in such as way as to maximize the train running options and enjoyment of building and operating the layout.

More trains on the tracks simultaneously, some hidden from view at times.

Ever run the New or Gauley River?  

The first thing that draws my attention in the track plan is the "X" in the center.  Yours is not strictly necessary because it is basically just a pair of crossovers between the orange and green lines.  These crossovers could and perhaps should be located elsewhere.  Also, the alignment of the tracks around and through the double crossover is interesting.  I'm curious what your thinking was.  I probably would have kept the two lines parallel and put a LH switch crossing to a LH switch and (some distance away) a RH switch crossing to a RH switch.

The most straightforward grade solution involves simply extending the grade sections by carrying them parallel to the elevated loop for a certain distance before they tie in.  This would give you a longer grade without screwing anything up.

@Long Hair posted:

The first thing that draws my attention in the track plan is the "X" in the center.  Yours is not strictly necessary because it is basically just a pair of crossovers between the orange and green lines.  These crossovers could and perhaps should be located elsewhere.  Also, the alignment of the tracks around and through the double crossover is interesting.  I'm curious what your thinking was.  I probably would have kept the two lines parallel and put a LH switch crossing to a LH switch and (some distance away) a RH switch crossing to a RH switch.

The most straightforward grade solution involves simply extending the grade sections by carrying them parallel to the elevated loop for a certain distance before they tie in.  This would give you a longer grade without screwing anything up.

Here is a SCARM (file attached) exercise I devised to demonstrate crossover switching possibilities.

It demonstrates how and why the 4x O72 Wye switches connected back to back to the 22.5 Crossover "X" allow for a wide curve radius double main line switching crossover in the least amount of linear FasTrack space.

It may not be necessary, but I like the look of it up front and when considering the bigger picture and I like how it saves linear space.

Regarding the grades, I've edited the original post for clarity.  I am primarily hoping for suggestions on grade reduction of the subterranean track.

I have O72, O54 and O45 mains with the reversing loops and yard incorporated into the O45 main on my 21' x 7' layout.  There are 16 turnouts... all O72.  I have a few scale locos... I can get my Visionline GG1 into and out the yard from the O72 main because of the larger turnouts ... something you may (or may not) want to consider.

I have thought about  your layout and it occurred to me to offer some food for thought.    You are going to spend a lot of time, money, and effort building the layout.    It will look very nice regardless of the track plan I'm sure.    However, after it is built, what will you do with it?     After you run a few trains around the multiple loops a half dozen times and congratulate yourself with a cold one, what is next?  

Have you considered maybe a track plan that is less intensive in terms of multiple loops and routes, but with more potential for operations requiring  you do something rather than watching them go around?      You could do a double track mainline still 2 loops and probably folded into a twice around to give some nice continuous running.    But you could put in 4-6-8 "staging" tracks under the mountain that feed to the mains and allow to store trains "offline"     then  you could run them through the visible layout based on a schedule - sequence or timing.     You put more town in the visible area with a station maybe small engine terminal, and a bunch of the industries you mentioned above.      Then a local could come of staging and switch the industries in the town  - car type for car type to keep is simple, and return to staging.     You could have a coal mine and have a train come in and exchange a dozen empty hoppers for loaded ones.      These are just some ideas that might make interest in the layout last longer than just loop running.

Was scary reading some of the comments for a bit.  I thought someone was going to mention Norton.

@Dennis-LaRock posted:

I have O72, O54 and O45 mains with the reversing loops and yard incorporated into the O45 main on my 21' x 7' layout.  There are 16 turnouts... all O72.  I have a few scale locos... I can get my Visionline GG1 into and out the yard from the O72 main because of the larger turnouts ... something you may (or may not) want to consider.

Dennis,  thank you for your comment.  Are you noting on my plan, that a Loco having a minimum curve requirement greater than O48 would not be able to negotiate the O48 curves on the inner reversing Loop?  If so, I have considered trying to make at least one of the reversing loops with a min O60, but doing so would lead to other compromises I'd rather not make.  Another layout with minimum O72 curves is something maybe for the future in a bigger space.

Maybe some day I will have some bigger (O54 minimum) Locos and they'd need to stay on the outer loop.  Right now all of ours will work on smaller diameter curves.

If I'm missing your point, please elaborate.

@prrjim posted:

I have thought about  your layout and it occurred to me to offer some food for thought.    You are going to spend a lot of time, money, and effort building the layout.    It will look very nice regardless of the track plan I'm sure.    However, after it is built, what will you do with it?     After you run a few trains around the multiple loops a half dozen times and congratulate yourself with a cold one, what is next?

Have you considered maybe a track plan that is less intensive in terms of multiple loops and routes, but with more potential for operations requiring  you do something rather than watching them go around?      You could do a double track mainline still 2 loops and probably folded into a twice around to give some nice continuous running.    But you could put in 4-6-8 "staging" tracks under the mountain that feed to the mains and allow to store trains "offline"     then  you could run them through the visible layout based on a schedule - sequence or timing.     You put more town in the visible area with a station maybe small engine terminal, and a bunch of the industries you mentioned above.      Then a local could come of staging and switch the industries in the town  - car type for car type to keep is simple, and return to staging.     You could have a coal mine and have a train come in and exchange a dozen empty hoppers for loaded ones.      These are just some ideas that might make interest in the layout last longer than just loop running.

Jim, thank you for continuing to think about my layout. I appreciate your suggestions.

The track, power, wiring, switches, scenery, etc. is already in house.  The time and effort of building a layout is very enjoyable to me.  After it's built, I expect to continue making refinements with scenery and electronics as well as running the wheels off the trains, so to speak.  Under the table, there is certainly room for expanding the number of passing sidings and staging areas.  Four is the number I want to start with.  As far as industry locations, there are at least 16 track side possibilities in this plan with 6 Operating Track sections and additional options for Uncouplers not yet shown in the plan.  Are you thinking there should be more industry than this?

Train sequence scheduling, yes.

Thanks again,

Steve H

New Forum member, model railroader since 1973.

@SteveH posted:

Maybe some day I will have some bigger Locos and they'd need to stay on the outer loop.  Right now all of ours will work on smaller diameter curves.

My largest loco can be reversed... but, not by circling through the reversing O45 loops.  I used transition O72 curves at the beginning of the O45 main and O54 main curves.  This allows the locos to pass the reversing loop turnouts onto the transition piece then backup (or go forward) through the reversing loops turnout.

I'm not a scale guy... while I love the scale stuff I have ...I prefer my conventional sized and LionMaster inventory.  The LionMaster Cab-Forward, Big Boy and Challengers look pretty sweet and are extremely smooth running through the O72 turnouts on my dinky layout.

Let me update my SCARM and I'll email it to you.  I too am planning a second level but decided to get started and just deal with level 1 first... and, BOY!  Am I glad I did!!!  The SCARM only deals with level 1... it does have the 2.3% grade which will eventually lead to the second level.

Building is generally fun, except when something does not go right!    but operating is fun too.    Some people however just like to build one.    Look at it a short while, then tear it down and build something different.

I did not see any obvious staging tracks on your diagram.   4 is good.    John Armstrong's recommendation was if  you think you need "N", build 2N+1.    I see them now, I was not understanding the different levels.    I would be tempted to add as many as will fit based on my experience.   

And I confess to not recognize 6 industrial sidings.    I did not consider the two small yards, and I only noticed 3-4 on the plans.    How many is enough is all personal preference.    I designed my layout with a lot because that is what I like.    I like to run local freights that switch industries along the line, and then go back to the yard.    Just a preference.

A sequence schedule will be fun, and you might be able to automate it with all the new electronic controls.    I am not a fan of that but it would be a fun display.

@Dennis-LaRock posted:

My largest loco can be reversed... but, not by circling through the reversing O45 loops.  I used transition O72 curves at the beginning of the O45 main and O54 main curves.  This allows the locos to pass the reversing loop turnouts onto the transition piece then backup (or go forward) through the reversing loops turnout.

Dennis, is something similar to this (with longer extensions) to reverse a larger Loco what you mean?

SteveH,

Glad you asked; I'm curious about how Dennis' explanation works, too.

Chuck

Yes... that is one way.   I only need one O72 curved section at each turnout to do it... just enough to get through the switch far enough to throw the turnout.  I probably should do a video but my photographic skills are very seriously lacking.

The point at least for me was to make effective use of the larger turnouts throughout the layout rather than use a mix of 36s, 45s, 54s, 63s, 72s turnouts etc...

Steve, not sure what to say. Overall I like the design with all the switching options and intricacies, but then I like to watch trains, not play with picking up and dropping off cars, etc. I’m not thrilled with the duck-unders or the width of the aisles. 10”-16” doesn’t leave a lot of room to turn around or even stand up after ducking. It’s going the make construction difficult, or at least troublesome, when trying to move around with tools and such. Having switches crossing the aisles may also make it difficult to build removable sections, though it’s certainly possible.

We’ve been on the road, so I’ve just been able to look at the design a bit during overnight stops, but today I was able to get the laptop out. I tried a number of combinations to reduce the hidden level grades with absolutely no luck. There are just too many switches and overpasses defining the length of space for grades. The only way to reduce them is to redesign things and give up too much of what makes things interesting, but then you already knew that, right? 😉

I’m not sure why there’s the green crossover in the lower left unless you intend to use that section as a small passing siding vs just a way to get to the storage tracks. Or you just want to use switches you already have. I assume the same is true for the 4 wyes and crossing, you already have the switches. While a double crossover with O72 switches is longer, it avoids the curviness of the wyes and lets you run at higher speeds on the mainlines. I prefer slower running and some curviness vs straight runs, so it doesn’t bother me, but there’s always the potential for derailments. I’m also kind of assuming you’ve already had some experience with that configuration if you already have the pieces.

@DoubleDAZ posted:

Steve, not sure what to say. Overall I like the design with all the switching options and intricacies, but then I like to watch trains, not play with picking up and dropping off cars, etc. I’m not thrilled with the duck-unders or the width of the aisles. 10”-16” doesn’t leave a lot of room to turn around or even stand up after ducking. It’s going the make construction difficult, or at least troublesome, when trying to move around with tools and such. Having switches crossing the aisles may also make it difficult to build removable sections, though it’s certainly possible.

We’ve been on the road, so I’ve just been able to look at the design a bit during overnight stops, but today I was able to get the laptop out. I tried a number of combinations to reduce the hidden level grades with absolutely no luck. There are just too many switches and overpasses defining the length of space for grades. The only way to reduce them is to redesign things and give up too much of what makes things interesting, but then you already knew that, right? 😉

I’m not sure why there’s the green crossover in the lower left unless you intend to use that section as a small passing siding vs just a way to get to the storage tracks. Or you just want to use switches you already have. I assume the same is true for the 4 wyes and crossing, you already have the switches. While a double crossover with O72 switches is longer, it avoids the curviness of the wyes and lets you run at higher speeds on the mainlines. I prefer slower running and some curviness vs straight runs, so it doesn’t bother me, but there’s always the potential for derailments. I’m also kind of assuming you’ve already had some experience with that configuration if you already have the pieces.

Dave, Thank you for your thoughtful, considered reply and the compliments.  I've been hoping that you would have time to look at my plan, I've admired the great help you've given to others here on the forum.

To answer your questions and concerns:

Regarding the width of the river/isles, I initially planned for them to be 18" wide, but since my daughter and I are slim and limber enough to fit into the smallest part of the aisles at 12", I narrowed them to make other accommodations for the track plan.  I have lots of experience working in tight places and am ok with it.

I also have enough experience taking FT switches apart, repairing, and tweaking them and removing/replacing FasTrack pins that I am confident the lift-out track and switches will work as planned for the 4 Custom Bridges I plan to make, each with dedicated wiring harnesses and connectors.

Did I already know that the only way to decrease the subterranean grades was to remove switches, well not exactly.  I know that would be one way, but I was hoping a track planning genius might be able to suggest a way to make it all work, perhaps with some tweaking.

The green siding at the lower left would serve two purposes: 1) as a main line passing siding, and 2) it would allow for adding more cars from the yard in the upper left to a longer consist without blocking the outer main line.

I do like curviness too.  I think it makes train watching more interesting.  As far as speed, there's a grade crossing there just East (to the right) of the X crossover, so if the engineer goes too fast thru town, he might be looking for other employment soon.

Thank you again for your thoughts and I hope you're enjoying your trip.  I'm a patient guy, so if you have a chance to look at this again after you get back home and you have any further thoughts or revelations about this plan, I'd welcome any additional input you might be willing to offer.

SteveH

Steve, if you’re okay with the aisles, etc., I’m okay. Based on your response, I’ve little doubt you know the challenges you’ll face during the build, but it sounds like you’re fully prepared with a plan, so I’ll be watching your progress with a lot of interest.

One thing I didn’t mention was the passenger line because I haven’t had time to play with it. The Lionel graduated trestle set rises to 5.5” and the elevated trestle set is at 5.5”. So, unless you have a car that requires greater clearance, the passenger line wouldn’t need to rise 7” if it weren’t for the tunnel portal to the right of the passenger terminal. Then I couldn’t help wondering how often you’d actually circle a passenger train on the gray loop. It seems to me the normal operation would be to rise to the terminal, drop off/pick up, then return to the main level. If you eliminated the gray crossover, there’d be longer runs to the terminal, so the grades could be reduced. And the left side of the mountain doesn’t all need to be 7” high, the gray tracks could be in a small valley rising to 7” at the terminal. Like I said, I haven’t played with it, so not sure about it.

@DoubleDAZ posted:

Steve, ...One thing I didn’t mention was the passenger line because I haven’t had time to play with it. The Lionel graduated trestle set rises to 5.5” and the elevated trestle set is at 5.5”. So, unless you have a car that requires greater clearance, the passenger line wouldn’t need to rise 7” if it weren’t for the tunnel portal to the right of the passenger terminal. Then I couldn’t help wondering how often you’d actually circle a passenger train on the gray loop. It seems to me the normal operation would be to rise to the terminal, drop off/pick up, then return to the main level. If you eliminated the gray crossover, there’d be longer runs to the terminal, so the grades could be reduced. And the left side of the mountain doesn’t all need to be 7” high, the gray tracks could be in a small valley rising to 7” at the terminal. Like I said, I haven’t played with it, so not sure about it.

Dave, Again I appreciate your thoughts and comments.  You helped me realize that I had been so focused on reducing  the grades from under the table, that I didn't pay enough attention to the elevated grades.  I worked on these some more and made some improvements.  I also added a lot of the planned buildings and extended the car roadways in the attached revised SCARM file.  The upper right (southwest) small "yard" now has one less spur to fit a dairy farm operation in that space.

I'll be using MTH "stone" trestles.  In many places plywood will be between the trestles and the bottom of the track.  As you suggest, less than 7" could work in some places, but the height and grades to/from the elevated loop aren't much of a concern for me at this point.  In these recent revisions to the elevated loop, the 2 Wye switches are further apart, and the grades leading to/from it are less.  I'll probably tweak the elevated track height as I'm building the physical layout.  The overall main level track elevation in the lower left area (Northeast part of the layout) is a little higher now.  This helped reduce the grade leading clockwise up to the Elevated loop.  It may seem silly, but I would like the option of being able to circle a passenger train on the upper loop sometimes.

So, changing focus back to the subterranean grades, it may not have been obvious before, but there was already a raised section on the main level above where the reverse S curve ducks under the table.  That raised section of track is now red for clarity.

I look forward to your thoughts on ways to possibly reduce the subterranean grades after your return home.

Thanks again,

SteveH

I too would be concerned about the narrow aisles as well as access to the storage area. But if access to these is just for the occasional derailment or scenery building, then it's not such a big deal. The narrow aisles will make convincing rivers.  I know you and your daughter are thin, but I don't know if the average train guy (like me) could squeeze in there.

Since this is your 10th layout, you clearly have a pretty good idea what you want and what you are doing. It's a very well thought out design with a lot of track work and should be fun to run trains on.

I look forward to watching your progress and BTW, welcome to the forum.

@Will posted:

I too would be concerned about the narrow aisles as well as access to the storage area. But if access to these is just for the occasional derailment or scenery building, then it's not such a big deal. The narrow aisles will make convincing rivers.  I know you and your daughter are thin, but I don't know if the average train guy (like me) could squeeze in there.

Since this is your 10th layout, you clearly have a pretty good idea what you want and what you are doing. It's a very well thought out design with a lot of track work and should be fun to run trains on.

I look forward to watching your progress and BTW, welcome to the forum.

Will, thank you for the Welcome and the compliments on the plan.

It's been a while since I've posted updates on this plan to include some improvements to lengthen the clockwise Underground exit grade (the one with the double track S-Curve inside the tunnels) which is currently at 6%. The improvements include raising the height of the Main Level track in places including above where the underground track easement begins to rise back up to the main level.

Here is a 3D view of the isolated track in question with a 6% grade, viewed from the back side of the layout.

I'm also attaching the revised SCARM file of this Track Plan.  Please note that to see the whole layout better, Layers can be turned on and off for clarity.

Suggestions on how the grade might be reduced without eliminating any of the existing features would be greatly appreciated.  To see what has already been discussed before replying, please read from the top first.  Back to Top - Original Topic posting

Thanks, Steve

Is what I highlighted in yellow the concerning grade?

Steve, I saw the discussion when you started it in early April, but didn't comment at that time.  It is quite an ambitious and well thought out plan.  I opened the SCARM file and saw the section you are questioning.  As I added levels, I realized your quandary about the 6% grade.  Every place I looked at thinking a modification could be made messes with clearances elsewhere.  I'll look again a little later.

@rplst8 posted:

Is what I highlighted in yellow the concerning grade?

That is the grade I was looking at.

@rplst8 and @Mark Boyce Mark and Ryan, that's correct the section Ryan highlighted in yellow is the one in question.  Thank you both for looking at this.  I look forward to your insights.

Mark, I appreciate the compliment and also am a fan of your layout.  The double drawbridge mechanism is really cool.

Thanks again, Steve

.

Thank you, Steve!  I only wish I had more room to add some more operation, but on the other had am happy I have what I have.  If I had the room and your plan in hand, I don't think I would be able to build it with the skills and tools (or lack of both) that I have.  I really want to see this plan under construction!!

So the limiting factor is that the other part of the the double track needs to go under the top of the highlighted grade, but needs to clear the secondary at the bottom.

I don’t know whats in the empty space above, but I’d recommend moving the main line to where I have the red line.  That way you only have one overpass.  It doesn’t have to jut out that far, I’m just not that steady on a touch screen.  

This will let you start the grade earlier where I have the yellow line.  You’ll have to lower the industry on the right and then the part in blue will need to rise back up.

Just one idea.  I haven’t had a chance to mess with it in Scarm, but that’s sort of my first take.

@rplst8  I like the way you're thinking outside the box.  I've seriously considered this option, but it really is outside the box, literally.  It's outside the conditioned part of the house.  Here in North Carolina, it gets too hot in the summer and too cold in the winter to poke holes in exterior walls for the train to go through.  I've run the numbers, and it's not practical to insulate and condition this tiny space to gain another 8" of lateral space before running into the bottom of the rafters.

Left Side

Right side

Please pardon the mess,... I mean boxes of treasure

I see the area in question.  We lived in a house like that.  I used some of that space to store a few boxes, but it wasn’t suitable for much else.  Someone on this Forum cut holes in the wall and utilized a similar space for one track this past winter.  He has an access opening like we had making it relatively easy to get in there.  I don’t recall him mentioning climate control or if he has run into problems.  Regardless, if you know yours isn’t suitable, that’s all that matters.

@Mark Boyce  Thanks Mark. I talked with Dennis after reading his post about his holes in the wall.  I guess the weather is more conducive to that approach where he lives.

Yes, that’s who I was thinking of but didn’t recall where he lives.  I don’t think I would want to do it here in Pennsylvania either.

@SteveH posted:

@rplst8  I like the way you're thinking outside the box.  I've seriously considered this option, but it really is outside the box, literally.  It's outside the conditioned part of the house.  Here in North Carolina, it gets too hot in the summer and too cold in the winter to poke holes in exterior walls for the train to go through.  I've run the numbers, and it's not practical to insulate and condition this tiny space to gain another 8" of lateral space before running into the bottom of the rafters.

So I've spent some time looking at the SCARM file and I'm at a loss. I think any reduction of those grades would require serious reconfiguration of the layout and/or removing features of the railroad.

If you did go the tunnel in wall route, what if you put "doors" on the holes so they could be closed when not in use?  That would save on heating/cooling costs.  Another option would be to remove that storage area entirely and take the ceiling line down to the floor with drywall.  You only need room enough for a double track mainline to implement the modifications I proposed, and 8" should do it.

Probably not what you wanted to hear, but I'm out of ideas.

@rplst8 posted:

So I've spent some time looking at the SCARM file and I'm at a loss. I think any reduction of those grades would require serious reconfiguration of the layout and/or removing features of the railroad.

If you did go the tunnel in wall route, what if you put "doors" on the holes so they could be closed when not in use?  That would save on heating/cooling costs.  Another option would be to remove that storage area entirely and take the ceiling line down to the floor with drywall.  You only need room enough for a double track mainline to implement the modifications I proposed, and 8" should do it.

Probably not what you wanted to hear, but I'm out of ideas.

Ryan, I really appreciate you taking the time to look at this question more closely and for the options you've suggested.  In the future, I may or may not decide to go the route of extending the mainline into the storage area (insulation, etc.), but right now it's not a realistic option for me considering the financial expense and time involved to do that renovation.  I've also considered the wall hole door/plug option, but in the winter, warm air (@ 45-50% relative humidity) rushes into that opening and within a few minutes begins condensing on everything in the storage space (at a much colder temp.) creating serious moisture issues.  Also FasTrack zinc pest is a concern at higher moisture levels (and I'm not interested in switching to another type of track).

Given the greatly appreciated time many of you and I have puzzled over this question, I'm starting to be inclined (no pun intended) to go ahead with this plan. In the construction phase, where possible I will look for ways to reduce the vertical distances between overlapping tracks on different levels, from the planned 7" to the minimum I can get away with (using thinner plywood, brace orientation and ~5-1/2" overhead clearances from the bench base).  I'm not planning to use a layer of any sound attenuating material under the track as our household is not bothered by the SPLs of trains running on FasTrack mounted directly to plywood.  Any taller cars can take one of the two mountain bypasses.  This combination of approaches should help reduce the grade to closer to 5%, maybe a little less.

Thanks again to all of you who have offered your time and suggestions on this question.

Steve, I can understand what you mean about warm air rushing into that uninsulated area and getting condensation.  Ours in Virginia was of older construction and there wasn't sufficient ventilation as our 1968 house here in Pennsylvania has.  In fact, the two bathroom fans aren't vented to the outside, but the galvanized pipes are just vented to the open attic space.  Occasionally, I see condensation on one of those.

I have 5 1/2" clearance on my track that runs under the upper track.  Since I won't run any tall, modern cars, it is enough.  I go along with your thoughts of starting to build and see what you can do to get to the minimum clearance.  Mountain railroading can just use more engines to get the cars to the summit.

The Great Knee-Wall Question for Attic Dwellers.  I understand the concern... but what is the reality?   I, of course, did the cutout.   You can  fit 2" (or, double it 4" or triple it 6") foam board cutouts in the openings when not in use.   You can do it as a test without running the track... it's a couple of small patches if it doesn't work out.   You will probably be doing some Sheetrock taping during the build anyway... just my 3.14159 cents.

Rock On!

@Dennis-LaRock Dennis, thank you for your encouragement, unfortunately it's wishful thinking.   I have already tested and experienced the reality of the moisture issues I've described above.  I've also gone to great lengths to stop and prevent them.  Here in NC and in other cold winter climates, condensation on cold surfaces above a living space is to be avoided.