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

[learmoia]

I'm working on a layout design where the layout is split across two sections of the basement. Between the two sections is a 10' gap which is the pathway between the stairs and the storm shelter.  The wife requested that the area be kept 100% clear when not running the layout. -- No Duck unders allowed.

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I'm planning to span the 10' division with a removable rolling bridge that would roll into one section of the layout area.

Initially I was planning to just have a single or double track span.. but the overall design would be better if I can utilize the bridge 'space' to include a small arrival /departure yard for a local that serves a large auto parts plant, as well as the main line on a slightly lower level.

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But should I expect reliable operations over the course of time if the bridge handles 2 levels of track with multiple joints at each end.

The Gray track is the upper level - Auto parts plant and what would be the arrival/departure yard. -- The Blue tracks are the main line which would drop down to run below the auto parts plant then come back up to the regular level.

There is plenty of time to work out a reliable solution.. but I'm wondering if I am asking for years of headaches and abandon the idea.

Thanks - Ian

Few more notes... The Red Circles are 36" Minimum Isle markers.... Overall size is roughly 43' x 45' -- and this will be N scale..

[nkalanaga]

I can see a lot of possible problems, but then, I'm a pessimist by nature.  Here are a few, and possible solutions.

1:  The wheels probably won't be round.  Most consumer chair/furniture grade wheels aren't.  One possible solution would be to make the bridge slightly lower than the layout.  Then, leave an "underlapping" section at each end, with alignment pins in the main layout.  The gap wouldn't have to be more than a quarter inch or so, and the pins would only stick out that much.  When the layout is rolled into place, it would be raised and anchored with C clamps, ensuring that it aligned perfectly, both horizontally and vertically.

The same thing could be done with removable bolts, preferably in metal sleeves to prevent wear in the holes, which would look better.  But it would also almost require tools for installation and removal.  Which would work better is something for you to decide.

2:  Track alignment problems tend to increase exponentially with the number of tracks.  One track is easy to align.  Two are possible.  Beyond that I imagine you'll have to use an Ntrak gap filler method, unless both sides of the joint are made from absolutely stable materials.  Any changes from temperature or humidity will affect the track spacing, and make alignment very difficult.

3:  Two levels more than doubles the problems.  You'll have all of the track alignment issues on both levels, independent of each other, plus any variations in the vertical separation of the two levels, plus the possibility that the two levels may themselves change lengths at different rates, meaning that one level of the bridge could be the right length, and the other won't fit.  I certainly wouldn't try to put both levels on one unit, wheeled or otherwise.

Now, a few questions:

How wide is the actual door to the storm shelter?  If it's less than the width of the shelter, you can shorten the bridge, as only the actual door should have to be bridged. 

Could you run the layout THROUGH the storm shelter?  Unless the walls have to be airtight, and I can't imagine why they would, a hole big enough for N scale double track won't affect the strength.  Then put the yards wherever there's room, around the walls, and you won't need any removable track.  Just four holes, one for each level, on each side, and the door is totally unobstructed.  There should be room behind the furnace and water heater for at least a single track, since most aren't installed tight against the wall.

[learmoia]

I can see a lot of possible problems, but then, I'm a pessimist by nature.  Here are a few, and possible solutions.

1:  The wheels probably won't be round.  Most consumer chair/furniture grade wheels aren't.  One possible solution would be to make the bridge slightly lower than the layout.  Then, leave an "underlapping" section at each end, with alignment pins in the main layout.  The gap wouldn't have to be more than a quarter inch or so, and the pins would only stick out that much.  When the layout is rolled into place, it would be raised and anchored with C clamps, ensuring that it aligned perfectly, both horizontally and vertically.

The same thing could be done with removable bolts, preferably in metal sleeves to prevent wear in the holes, which would look better.  But it would also almost require tools for installation and removal.  Which would work better is something for you to decide.

2:  Track alignment problems tend to increase exponentially with the number of tracks.  One track is easy to align.  Two are possible.  Beyond that I imagine you'll have to use an Ntrak gap filler method, unless both sides of the joint are made from absolutely stable materials.  Any changes from temperature or humidity will affect the track spacing, and make alignment very difficult.

3:  Two levels more than doubles the problems.  You'll have all of the track alignment issues on both levels, independent of each other, plus any variations in the vertical separation of the two levels, plus the possibility that the two levels may themselves change lengths at different rates, meaning that one level of the bridge could be the right length, and the other won't fit.  I certainly wouldn't try to put both levels on one unit, wheeled or otherwise.

Now, a few questions:

How wide is the actual door to the storm shelter?  If it's less than the width of the shelter, you can shorten the bridge, as only the actual door should have to be bridged. 

Could you run the layout THROUGH the storm shelter?  Unless the walls have to be airtight, and I can't imagine why they would, a hole big enough for N scale double track won't affect the strength.  Then put the yards wherever there's room, around the walls, and you won't need any removable track.  Just four holes, one for each level, on each side, and the door is totally unobstructed.  There should be room behind the furnace and water heater for at least a single track, since most aren't installed tight against the wall.

Nahh.. can't (not going to) run through shelter.. it's concrete walls on all sides (ceiling too)..  after the shelter then bathroom then work shop..  all the walls in the basement are concrete..  (I know I could take one out here and there but i don't gain anything)
(Not all walls are show)

I need to try a couple other ideas to try that would allow a single level bridge.

 

[central.vermont]

Ian,
Some questions and suggestions. I know you said no duck unders but what do you have for overhead clearance? Was thinking you could just raise the whole thing straight up to the ceiling if you have the clearance. Also was wondering what the area on the left is? Can you come around the other way through this area and then under the stairs?
Jon

[DKS]

A few questions before offering any suggestions.

1) How often would you anticipate the need to remove this section?

2) In the space marked "Shop" and "Furnace, etc.", what are the clearances near the removable section?

3) What are the elevations above the floor for the tracks crossing the span?

4) Are you married to having two levels on this span?

[eric220]

Would punching through the wall and going around the walls of the shelter/shop are be an option? Even if it's just a minimalist shelf, it would eliminate the need for the duckundsr and add length to the run.

[learmoia]

Well I realized I needed to go back and get some specific measurements that I had estimated before we moved in.. and the results change the space to where I can sufficiently model the auto parts plant in a different area and the bridge can now be single level / double track...

But lets answer some questions..

Ian,
I know you said no duck unders but what do you have for overhead clearance?
-- Layout height would be about 50" -- 8ish' basement floor to the floor joists on the main floor.. 

Was thinking you could just raise the whole thing straight up to the ceiling if you have the clearance.
-- I had considered doing a Helix up to the floor joists and running the bridge between the joists into the other room then Helix back down. 
---- Part of me really wants to do that.. but I'm not sure if I can squeeze a sufficient helix in the bottom half of the layout.

Also was wondering what the area on the left is? Can you come around the other way through this area and then under the stairs?
-- It will be the desk and workbench area, If I went that way to go under the stairs then I'd have to pass the wife's lapidary area washer and dryer.. (Red cross hatch area).. I don't think I could get away with that..

-- and since all walls are concrete block it will be tricky to go through any walls.. (I could, but if I don't have too.. I'd rather not.. and I have plenty of options where I don't have too..

A few questions before offering any suggestions.

1) How often would you anticipate the need to remove this section?
... It would either be removed for a long period of time and in place only for operating sessions.

2) In the space marked "Shop" and "Furnace, etc.", what are the clearances near the removable section?
??... Not sure what you mean..  I had considered running along the opposite side of the wall but the water heater is up against the wall so I can't sneak a track through there.

3) What are the elevations above the floor for the tracks crossing the span?
50" What would be normal layout height.

4) Are you married to having two levels on this span?
Nope.. not at all, was planning on single level span until I had this idea.

Would punching through the wall and going around the walls of the shelter/shop are be an option? Even if it's just a minimalist shelf, it would eliminate the need for the duckundsr and add length to the run.

-- I could but there are several walls that are not shown.. I'd have to go Shelter - Bathroom - Shop - into the other room.. I don't gain any main line doing it that way.. and I'd have 3 concrete walls to go through.

I'll send another drawing with the revised dims in a bit and added detail.. I also need to explore the Helix overhead idea a bit more.

~Ian

[learmoia]

Here is what it looks like with a double helix while maintaining the 36" min isle width. 

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..

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[mighalpern]

Per your new drawing are you having to go thru two concrete walls??  If you have to do that anyway I would consider using a lift up section that uses high quality drawer sliders to slide the section up into the ceiling. You could still cut the holes at normal layout level and then bolt the sliders on the inside of the concrete walls.  My friend has done this in a closet to lift from the lower area to the upper, about 20 inches and uses latches and some weights to hold in place, granted it does not span 10 ish feet, but i think you could make a light stiff frame to make it work.

just my 2 cents 

Miguel

[learmoia]

Per your new drawing are you having to go thru two concrete walls??  If you have to do that anyway I would consider using a lift up section that uses high quality drawer sliders to slide the section up into the ceiling. You could still cut the holes at normal layout level and then bolt the sliders on the inside of the concrete walls.  My friend has done this in a closet to lift from the lower area to the upper, about 20 inches and uses latches and some weights to hold in place, granted it does not span 10 ish feet, but i think you could make a light stiff frame to make it work.

just my 2 cents 

Miguel

No.. This time, I'm going up a Helix to the floor joists, then running in between and parallel to the floor joists across the gap then back down the other helix.

~Ian

[peteski]

Two 18.5 turn helices to get across that opening?  That is 37 turns!  When your train enters that area you might as well go to your crew lounge and have some coffee while watching a railroad-themed video.    You will have some long operating sessions!

[learmoia]

Two 18.5 turn helices to get across that opening?  That is 37 turns!  When your train enters that area you might as well go to your crew lounge and have some coffee while watching a railroad-themed video.    You will have some long operating sessions!

Hmmmmmm..... 

Lets say we run a scale 25mph across the gap.. it would take about a half hour to get across the gap..

... Maaaaybe this is a bad idea..

~Ian

[peteski]

Hmmmmmm..... 

Lets say we run a scale 25mph across the gap.. it would take about a half hour to get across the gap..

... Maaaaybe this is a bad idea..

~Ian

LOL!  You would probably be the first modeler ever to use slow-clock for your operating sessions!   

[Point353]

I'm working on a layout design where the layout is split across two sections of the basement.

Here is what it looks like with a double helix ...

Suppose you were to limit the layout to one or the other room, but make it a double-decker, with one relatively shorter helix connecting the two levels. Would that give you a sufficiently large layout and/or long enough run?

[learmoia]

LOL!  You would probably be the first modeler ever to use slow-clock for your operating sessions!   

Would that make it modeling a fast clock in real time..?