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Adding 30" curve on foam sub-roadbed

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Adding 30" curve on foam sub-roadbed
Posted by kasskaboose on Friday, September 08, 2017 1:20 PM

How to lay a 30" track on foam?  It makes sense that I need a sheet of foam wider than 2'. I'm conceptualizing a 12x14' U-shaped HO layout and want to accomodate six-axle locos.  Putting them on 30" curves avoids derailment.  I've consulted tons of resources (including Armstrong's book) and seek to avoid repeating notable layout errors.  Some layouts show 30+" radi on a two foot section, so I know that is possible.

For background: On my current layout, which is going to get dismantled, I have a 30" radius on 4'x8' foamboard.   The locos run easily around it, but what a pain with the scenery!

Thanks!

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Posted by cuyama on Friday, September 08, 2017 1:34 PM

Sorry, but I am confused by your question. Obviously, a 30" radius half-circle won't fit on 4-foot-wide benchwork, since the diameter is over 60". Radius and diameter in model railroading.

If you are asking how to lay out a smaller segment of 30" radius curve on an area of roadbed, a trammel works well. This can be as simple as a yardstick with holes for a pencil at the various radii needed. A camera tripod can support the fixed end of the trammel in the aisle for broader curves.

Google search "yardstick trammel"

And if you are asking something else, more clarity might help others help you.

(Or maybe everyone else understands and I’m just not getting it.)

Good luck with your layout.

Tags: Trammel
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Posted by 7j43k on Friday, September 08, 2017 1:38 PM

It sounds like you are planning on laying roadbed and track on unsupported foam.

You can put several pieces of foam side-by-side.  Then you can put "any" curve you want on top.

At the joints, I recommend a wood support.  I suppose you could glue the pieces together instead, or in addition.  A problem with the wood support is when/if the foam sags--you'll then have a "high spot" at each joint.

I wouldn't do it.  Others likely would.

I only use foam for scenery, not track support.  And I suspect I won't be using foam anymore, anyway.

 

Ed

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Posted by ROBERT PETRICK on Friday, September 08, 2017 2:00 PM

cuyama

Sorry, but I am confused by your question. Obviously, a 30" radius half-circle won't fit on 4-foot-wide benchwork, since the diameter is over 60". Radius and diameter in model railroading.

If you are asking how to lay out a smaller segment of 30" radius curve on an area of roadbed, a trammel works well. This can be as simple as a yardstick with holes for a pencil at the various radii needed. A camera tripod can support the fixed end of the trammel in the aisle for broader curves.

Google search "yardstick trammel"

And if you are asking something else, more clarity might help others help you.

(Or maybe everyone else understands and I’m just not getting it.)

Good luck with your layout.

Maybe his proposed curve doesn't sweep a full 180 degrees. Maybe 90 degrees around the corner of the U-shape.

I agree, more clarification and/or sketches would help.

Robert 

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Posted by kasskaboose on Friday, September 08, 2017 2:03 PM

Thanks for the fast responses and helpful visual.  The 2" foam board would rest on 1x4's across the top every 3'on L-girder tables. 

My concern is trying to reach the foam when it supports a 30" curve.  Should I instead use a 22" curve for the SD40-2s?

What I'm trying to understand is how to have a broad curve on a layout to handle six-axle locos.  There are plenty of HO layouts that have broad curves.

Does that help?

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Posted by cuyama on Friday, September 08, 2017 2:25 PM

kasskaboose
The 2" foam board would rest on 1x4's across the top every 3'on L-girder tables. 

That's likely too far between joists, in my experience. 16"-24" is more typical.

kasskaboose
My concern is trying to reach the foam when it supports a 30" curve.

Since most folks can only reach 30" across a scenicked layout without damage, that's a valid concern.

kasskaboose
What I'm trying to understand is how to have a broad curve on a layout to handle six-axle locos.  There are plenty of HO layouts that have broad curves.

Yes, but usually not made from solid 4'X8' sheets.

You need aisles into the layout (better) and/or access hatches.

This HO layout has 30" minimum radius curves and relatively narrow benchwork. Note how the benchwork curves around to allow aisles accessing the scenes.

 

... or maybe I still don't understand your question.

Good luck with your layout.

Byron

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Posted by rrinker on Friday, September 08, 2017 2:40 PM

 This is part of my old layout, the curves are 30" and then some, on 2' wide foam sections

Being a donut, there was access from the inside and outside, except for the back right corner (diagonal from this view - behind the camera) which was in a corner of the room.  Even so, even the outer track of the double track was within 24" of the inside fo the layout.

 Wow, looked at the date on the log for that picture, 12 1/2 years ago. 

                            --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by kasskaboose on Friday, September 08, 2017 3:35 PM

Thanks for the picture and additional help.  Perhaps what makes more sense is putting in a 30" curve that eases into a straight track over a 30" elongated "C-shape" configuration.  Thnking more about the curve, that might work better.

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Posted by BATMAN on Friday, September 08, 2017 4:15 PM

I am not sure exactly what you are trying to do so I will just post a few pic's that might give you some ideas.

Here you can see I used spline and foam to lay the track on. On the left, the spline butts up against the foam where the track then sits on cork and foam. One change I would make next time would be to put spline or plywood under mainline track everywhere on the layout. Foam is great for supporting yards and secondary spurs and such, however, it is a little too rock and rolly for the mainline track.

 

Foam needs more support than you are suggesting. I used lap joints on all these 1" x 4"s Just clamped them all together and ran them through the saw. They all then fit together perfectly. They were glued and screwed together. Solid as can be, does not bend or twist. This bench is 18' x 6'.

 

If I had used spline all along the main I would not need to have used cork as the bevelled edge is built into the spline.

 

   Access is important so make sure you provide it for your sanity.

 

Here a hatch is required to reach the rear of the bench. I can put the square of foam back in when I don't need access, it will be invisible when in place.

 

This unsupported length of spline  (over 4' long) over a canyon to the floor has been there for years and has not sagged even a mm. One advantage over plywood.

This bench is 6' x 18' and it is a bit of a pain to work on the centre part, however, on the rare occasion I climbed up on it to work on it, I put a 18" x 30" piece of plywood down on the foam and kneeled on it and there was no evidence I  (all 200LBS) had been on it afterwards. Once completed, I should rarely need to reach the middle.

Try thinking outside the box when issues arise. Materials and methods have changed a lot over the years. Be cautious of those that say there is only one way to do things, you can use many methods on the same layout, from bench work to scenery construction to track laying. 

Brent

It's not the age honey, it's the mileage.

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Posted by BigDaddy on Friday, September 08, 2017 5:02 PM

Aside from agreeing with the comments for and does more support, foam can shrink.  I've seen posts here, where people recommend ageing your foam for 6 months. 

 

Henry

COB Potomac & Northern

By the Chesapeake Bay

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Posted by BATMAN on Friday, September 08, 2017 6:18 PM

 

It is when I run my camera around the layout I notice the foam is more rolly than spline or ply. The camera really has the ability to point that out as it is so top heavy.

When I decided to build this layout, I wanted to try something new, so spline and foam were it. The determinations are thus far IMO, spline is better than plywood as far as cost, strength (more solid) and the fun factors are concerned. I loved laying the spline. Foam is not substantial enough for mainline sub roadbed, but great for yards, spurs and whathaveyous. With 2" foam, putting in ditches, lakes, and creeks or a tunnel under the track for cars or cattle is easypeasy.

I find foam for mountains great, that being said I have used various forms of goo for such things and they are all fun to use.

Caulk or track nails, I don't understand why people need to defend their choice, both work and each has various advantages over the other. IMO.

Spline is quieter than plywood and if you are rich, cement board is completely silent. All you hear are the metal wheels on the track, which is louder than you would expect.

Cowboy

Brent

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Posted by rrinker on Friday, September 08, 2017 10:37 PM

 2 foam layouts, and the support spacing was 2 foot on center. No sag issues, and it is more than strong enough to support HO trains. This is with 2" foam. 1" foam likely requires more support. 

 While neither layout really got to the scenery stage, the one pictured above saw a LOT of train running, and not just modern mostly plastic stuff - a couple of Bowsers, a bunch of brass, and a pair of Cary lead bodies on Athearn chassis got plenty of run time over the years it was up and runnign with absolutely no problems. That layout had no additional support - 1x4 box frames with a cross brace every 2', foam glued right on top of it. AND under each turnout there was about a 2" square hole, the Tortoises were top mounted following some pictures I found on a Freemo site. No sags, cracks, or gaps, and I didn't have to be particularly cautious not to put any weight on the layout. Could I climb on it? No, but you'd need to make the benchwork out of 2x4's on 16" centers with at least 3/4" plywood to support my level of weight.

                            --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by railandsail on Monday, September 11, 2017 10:30 AM

So what type of spline were you using Batman?

 

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Posted by BATMAN on Monday, September 11, 2017 1:43 PM

Hi, Brian.

I used hardboard (pegboard without the holes). Seven 1" strips of 1/4" Hot glued together and then screwed with drywall screws. You can get a whole lot of sub-roadbed out of one sheet and like I said, no cork or foam roadbed required, so that is also a saving.

 

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1

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Posted by railandsail on Tuesday, September 12, 2017 3:14 PM

BATMAN

I used hardboard (pegboard without the holes).

I think that is the same material we call Masonite here in the states?

When you build with this, what are the procedures do you go thru to glue, screw, and get the bend in it you are looking for??

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Posted by BATMAN on Tuesday, September 12, 2017 4:45 PM

I think hardboard and masonite are the same things, Masonite is just a brand name ( I think )

I started with 1" x 4"s as risers simply because I had a lot of them on the wood rack in the workshop. You can use 1" x 2"s however, 1" x 4"s offer a little cheat space when placing the spline on top of it.

 

I bought a bunch of cheap clamps for a dollar each at Sears, a few broke so I am glad I bought extras. You can also find them at the dollar store ( usually ). The 1" x 4" risers were screwed to the open grid and could not be placed equidistant as anywhere there was a curve the height at which the riser was placed would change. A little high school math makes it easy to figure out riser height.

 

Here you see a nail in the top of the riser. This represents the centre spline. After you lay two or three on one side the nail comes out and the centre spline takes its place. After I put down two the shape was held in place firm.

I used a hot glue gun and just glued half of a length and when dry, glued the second half. Of course, there was staggered overlap so all the joints were not in the same place. After all seven layers were done I put drywall (sheetrock) screws down through the centre spline into the riser from the top, and through the sides alternating sides as I went. Be sure to drill holes before screwing, as masonite splits and does other weird things if you don't.

 

Some of my splines at the ready. Don't forget to run off some with a 45 degree angle for the tapered out side pieces. I took my saw outside to run the sheets through and I am glad I did, the sawdust cloud was quite something. It was fun though.

Some online spline tutorials say to cut the splines at 7/8" wide. I made mine 1" as it made the math easier.

With the cookie cutter method, a lot of people tend to cut out the plywood at set radiuses. IMO this gives a layout a punched out less real look as all the curve(s) are to uniform. With spline, you can easily have a 32"R curve nicely open up to a 38"R curve and it looks like the track flows beautifully.

This stretch of spline over my canyon to the floor, has been there for nine years (I think) and hasn't sagged a bit. It is over four feet long and has had a lot of trains over it. Someday I'll cut it out and a real bridge will take its place.Laugh

Spline is really solid, cheap and doesn't require cork or foam roadbed on top of it. It went up so fast I was disappointed when I was finished as I was having a lot of fun with it. I would absolutely use spline again if it was right for the job.

One other thing I did was to vary the grade. It changes back and forth from between 1 percent to 2 percent. That goes along with my not looking "stamped out" philosophy.

Hoped this helped.

 

Brent

It's not the age honey, it's the mileage.

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Posted by railandsail on Tuesday, September 12, 2017 9:07 PM

BATMAN

 

This stretch of spline over my canyon to the floor, has been there for nine years (I think) and hasn't sagged a bit. It is over four feet long and has had a lot of trains over it. Someday I'll cut it out and a real bridge will take its place.Laugh

That's impressive. What sort of temp/humidity variations does your layout experience?

I also found this very interesting reference:
http://s145079212.onlinehome.us/rr/howto/splines/

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Posted by TheK4Kid on Tuesday, September 12, 2017 10:01 PM

I used two inch thick foam on my layout, with no problems.

My layout as of now is 6 feet wide  by 24 feet long and supported by a wood latticet my layout of three 6 foot wide by 8 foot long sections in my basement,  It is quite strong. My choice of foam was that I if I ever moved, it easily comes apart in three 6 ft by 8ft sections, and is light weight enough to eaily be taken up my basement stairsI cut a 4 by 8 foam sheet into two 2 ft by 8ft sections and glued it to 4 by 8 sheets to get a 6 foot width.

I built a light weight but very strong wood frame.Once my wiring is all in place, I tried tacking fiberglass insulation rolls and it quieted it doown so I have have no noise issues. My track is on fom road bed and I had no noise issues such as "drum effect".

POssibly this winter once being outside much  is not feasable ( I live in northeast Indiana)  I may add to my layout, once again using two inch foam.

My track radius at booth ends is 30 inch inside track, 32 inch radius outside track.

Even my BLI 2-8-8-2 steam engines work properly on this radius!

The legs on my layout unbolt, and i can tilt each section up on it's side and easily move each section up the basement stairwell.This is the reason I used foam.

I have two friends who used plywood and plaster and other materials and when they had to move, they essentially had to cut up or destroy their layouts. because they were too large, cumbersome and too heavy to man handle up a basemet stairs.

But I say to all of you to each his own! Use what you favor.

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Posted by BATMAN on Tuesday, September 12, 2017 10:03 PM

That website is more or less the way I do it. He uses six splines and I used seven so I could get the bevelled edges on either side. I thought it was John Fugate that used seven as well and that is where I got that idea from, I could be wrong. They don't show beveled edges in their diagrams.

Some have had issues with getting the top level, I overcame this problem by only gluing half of one spline at a time, this made it manageable and when I went to glue down the second half it lined up perfectly. I ran a Surform plane over it, but it wasn't necessary as I got lucky and it was nicely lined up. I filled a couple of pot holes where the edge of the spline got a chunk out of it with caulk and/or Dap, no biggie. 

I did take a plane to it after the fact to put a little super elevation in some of the curves. I marked the glass on a level and planed a gentle bank in and out of the super elevation taking my time I think I got it perfect.

Here on the West Coast temperature rarely goes below freezing and humidity is steady and you can see the layout is in a finished part of the house, We also have a high-end filter on the furnace and I have never had to clean the layout as dust is minimal. I have had no real issues with it.

On that website, it talks about hollow spline. I have done the same and put spacers in where I go to double track and then put together another seven splines.

Bringing terrain up to the lower edge of the bevel was a breeze. Something like this.

 

 

If you look at some of the youtube videos in my link you can get some different views of it. The videos are getting quite old now, but they give you some idea of the layout.

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1

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Posted by railandsail on Wednesday, September 13, 2017 8:08 AM

Thanks for that Brent. I believe you said you used hot-melt glue on your splines?

I assume you had no long term problems with that glueing method?

I image it is a bit cleaner that using liquid type glues, and would go a bit quicker??

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Posted by BATMAN on Wednesday, September 13, 2017 10:38 AM

The hot glue is still solid nine years later with no sign of delaminating. That 4' part has no screws in it and is still solid.

Get hot glue sticks with a slower setting time, as it allows time to get the top aligned up. By slower I mean maybe 45 seconds instead of 30 seconds, it goes fast. In the videos you can see some glue spider webs hanging down, these took seconds to clean up

Here I cut out the spline and put in a bridge. It was waaaay easier removing the spline to do that, than trying to cut out a chunk of plywood.

 

 Here a different bridge, same spot.

 

I made the piers out of foam using an I-beam to cut the grooves while watching hockey. After making a few, I got better and better at it.

 

I also used these cardboard strips cut to various radiuses to make sure I didn't go below minimum with the spline.

 

 

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1

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Posted by railandsail on Wednesday, September 13, 2017 11:05 AM

We have sort of hi-jacked this subject thread.

There is another couple of fellows interested in this subject over on this subject thread:
http://cs.trains.com/mrr/f/11/t/264923.aspx?page=3#2995058

I posted a couple of your observations over there. You might offer some of your expertese over there as well. Thanks for those photo-describtions.

 

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