# PVC Pipe Spline Roadbed



## rhyman (Apr 19, 2009)

Here is a new twist to a familiar type of roadbed construction. Indoor modelers have long used splines cut from wood, masonite, or Homosote to fabricate sturdy roadbed. Splines provide strength, good transition curves, and excellent sound deadening qualities. On the downside, they are labor intensive and time consuming to build correctly and may require stabilization to handle humidity and temperature variations. They also tend to deteriorate rapidly when used in an outdoor environment. 
I build my spline roadbed for my indoor Sn3 layout with pine lattice or with home-made strips cut on a table saw from redwood or cedar. I had planned on using the same technique for my new Fn3 outdoor layout. Lately, the price of wood has made this type of construction less attractive. I figured there must be a cheaper and better way to solve the problem. 

After completing a recent lawn sprinkler installation project, I had several left-over pieces of ½” and ¾” diameter PVC pipe. As I was lifting a length of pipe into the rafters for storage, I noticed that it curved gracefully in a wide arc. I thought to myself, “What a smooth transition curve.” Eureka … the light went on! After a brief bit of experimenting, I came up with a couple of interesting spline roadbed arrangements.

The following examples were all fabricated from Schedule 40 PVC pipe. This pipe is fairly rigid, but can be curved for radii down to about 8 feet for Fn3. To form tighter radii you can substitute a thinner walled PVC pipe, such as Schedule 125 or Schedule 200. You can also use other types of plastic pipe such as PEX. I have not yet done any experimenting with PEX pipes, but the construction techniques used should be about the same as those described for the PVC.

PVC and PEX pipe are available at most home improvement stores (Lowes, Home Depot, etc.) PVC pipe comes in 10-foot and 20-foot lengths. PEX pipe is available in 5-foot or 10 foot lengths, and also in 50-foot and 100-foot coils, depending on diameter. If you decide to use PEX, select diameters that are approximately the same external size of the ¾” PVC used in these examples. 

These examples do not include diverging splines (for turnouts.) To construct diverging splines, use the same technique as for wooden splines. Simply spread the outer splines to the required divergence angle and add additional splines to each diverging route as clearance is available. 
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The Fn3 roadbed for outdoor use is made from three adjacent splines of ¾” PVC pipe. I have developed two different arrangements for the roadbed. The first method uses three adjacent splines of ¾” PVC pipe as shown in Figure 1. The pipes are place side by side, touching each other, with staggered end joints. 










End joints are not connected. The three adjacent pipes are connected to each other with 2-inch long deck screws inserted from alternate sides at approximately 12-inch intervals. “Liquid Nails” construction adhesive is liberally applied to the top of each pipe and allowed to fill the “V” gaps between the pipes. Wood ties are laid on the tops of the pipes into the wet adhesive. Rail is spiked to the ties after the adhesive is cured. 

The roadbed is placed directly on the ground or supported by bricks as needed. This method of roadbed construction seems to work best for garden layouts where the track is laid at approximate ground level and where severe weather is not a problem.

The second method shown in Figure 2 is a bit more complicated, but it provides maximum strength. It also uses three splines of ¾” PVC pipe. The three pipes are arranged in a triangular cross-section. The two upper pipes have staggered end joints connected with ¾” PVC “COUPLING” fittings using PVC pipe glue.










The pair of upper pipes rest on a lower pipe made from approximate 5-foot lengths of ¾” pipe. The 5-foot sections are joined with PVC “TEE” fittings using PVC pipe glue. Variable length risers are made from scrap lengths of ¾” PVC pipe and extend vertically from each “TEE” fitting downward approximately 12 inches below ground level. The three splines do not touch each other except at “COUPLING” and “TEE” fittings. At all other points, there is a gap of approximately 1/8” between the three pipes.

I install the lower spline and vertical risers first. Then I assemble the upper splines and temporarily attach them to the lower spline with string or nylon cable ties. When the grades, curvatures, and general alignments are correct, I fill the gaps between the splines with expanding foam insulation. After twenty-four hours, this insulation is cured and will hold the splines in the desired position. After sanding or scraping the top surface flat, I attach either wooden ties for handlaid track or flex track with polyurethane glue or construction adhesive.

This method of roadbed construction seems to work best for garden layouts on uneven terrain. It is ideal for extended lengths of track above grade level, or for garden layouts in areas where winter frost heaves wreck havoc with conventional track laying methods. 

PVC pipe is light-weight, strong, inexpensive, readily available, and easy to assemble. It is impervious to changes in temperature and humidy. PVC can be placed safely on or in the ground without worry about rot or termites. In addition, PVC pipe offers a nice feature not available with traditional spline construction – with Method 2 you can route electrical wiring through the splines just like electrical conduit. (I use battery power and DCC radio control, so I don’t have any wiring to worry about.) I urge you to give PVC pipe splines a try – you may never go back to wood again! 

Bob "Sn3nut" Hyman


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## RimfireJim (Mar 25, 2009)

Nicely written article, Bob. A couple questions:

1. How long have you had this system in use? Has the alignment stayed true between the posts at 5' intervals in your Method #2? (I'm guessing you have earth fill up to the PVC to help support the span.)

2. Re. the expanding foam: Are you using the stuff in the spray can sold for insulation, or the two-part mix-it-yourself kind? Any problem with it running out the 1/8" gap between pipes on Method #2?


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## nkelsey (Jan 4, 2008)

Are you painting or covering the pvc and foam? I know the foam degrades, and I seem to remember the piping will eventually degrade from UV.


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## rhyman (Apr 19, 2009)

I built three experimental sections of PVC spline roadbed last October and displayed them at the St. Louis Area Narrow Gauge (SLANG) semi-annual meet. Two of the sections were the ones described in my article. The other was a Sn3 section made with 1/2" PVC pipe. The only difference between the experimental sections and the ones described is the rail size. I used Code 250 on the experimental sections, but have now switched to code 215. After the SLANG meet, I brought the sections home and "planted" the Fn3 sections in my back yard to see how they would hold-up over the winter. No paint, no ballast, no earth fill - just the raw PVC sections with ties and rail. The purpose was to check-out how the various materials (PVC pipe, wood ties, aluminum rail, steel spikes, adhesives and foam) would react to the temperature and humidity extremes here in central Oklahoma (around zero in winter; around 100 now.) The section built with Method 1 is just lying on the ground. The section built with Method 2 is about a foot above ground level, with the vertical stanchions sunk about a foot into the ground and with a four foot span between stanchions. After eight months, they still are in the original condition - no sagging or warping is apparent. There is a little bit of yellowing of the exposed PVC pipe due to UV, but otherwise no apparent damage. I am now using the methods decribed to build my new outdoor layout. I have only recently started construction and very little of the actual track has been laid - only enough to test tun my new K-27. Most of the layout is being built using Method 1, but I am putting in a few sections of the triangular cross-section described in Method 2 to temporarily bridge areas where trestles will eventually be built. The expanding foam used for Method 2 is "Great Stuff" insulation. It comes in a spray can from Lowe's or Home Depot. I have used this same foam to seal between the rocks on my garden ponds and waterfalls. One of my waterfalls has been operating for almost ten years non-stop and I can see no degradation of the foam, although in all fairness the foam is not exposed to the UV. It does, however, stay wet most of the time. For the layout, I plan on covering the PVC roadbed with earth and rock fill, so I am not too concerned about UV degradation over time. For the exposed above ground sections, I will probably give the roadbed a coat of spray paint just to hide it before I add the ties and rail. At the rate I'm going, it may be a while before I get around to building the trestles. By the way, the foam does not drip out from the 1/8" gaps when being applied. It does set-up a bit quicker if you mist the PVC pipe with water before applying the foam.
Bob


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## Trains (Jan 2, 2008)

Bob,

I think you are going to have problems, I used 1x2 PVC and there is some sag in it with pipe spaced 2 foot apart. I used 1 1/2" pipe for my supports
and there is some give in the one two feet and longer.


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## Pete Thornton (Jan 2, 2008)

Bob, 

Great minds think alike. Roger built his huge outdoor layout using your method 2 and we've been enjoying it for years. Here's a couple of pics: 



















The roadbed is foam and it is all painted to prevent UV degradation ( and look less like PVC pipe!) 

Ken's railroad is similar:


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## rhyman (Apr 19, 2009)

Just did a quick experiment. Went outside and first measured the level on the above-ground Method 2 experimental section. It was still pefectly level without any sag. I placed a short piece of 2" x 6" board crossways on the rails at the mid-point of the span. I then stacked fifty pounds of concrete blocks on the 2 x 6 board. I again measured the span for level. It had slightly deflected (less than 1/8" of an inch sag at the midpoint.) I removed the weight and checked it again. The span returned to perfectly level. I put the the weight back on the span and will leave it there for a day or two and see if I can cause any permanent deflection. Will post results later. 
Bob


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## pinewoods (Jan 20, 2009)

Great and timely(for me) article. Athough I must admit I am annoyed at myself for not thinking about the addition of the third pipe in the middle. I have experimented with a few methods of making ladder with plastic electrical conduit but was not satisfied with any 'rung' design that I came up with. Electrical conduit is more UV resistant than PVC and should work well with method 1. Conduit fittings are quite different from pipe fittings so I don't think it would work with methed 2. I know what I am going to be doing over the July 4th holiday! 

Thanks Bob!!


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## astrayelmgod (Jan 2, 2008)

My experience with Liquid Nails was that it turned to powder in about 2-3 years here in Southern California. 

have sprinkler pipe that was sub-optimally installed (by me) and isn't covered with dirt. It's in shade most of the day, and is still fine, if a bit yellow, after nearly 20 years.


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## Don Howard (Jan 2, 2008)

Adding on to Pete's photos:


His first one is from 2004.


Here is nearly the same location today(well, 03/29/09)















Here are two underside pics from 3/29, too.























I'm pretty sure these are the same pipes when I was there April 2006.
The paint seems to have protected the pipes well.


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## Dr G (Jan 16, 2008)

Great idea!!! I think I just might use this on my next layout. Couple of thoughts: if you don't bury the PVC in dirt I would paint it--I ran some PVC above ground around the addition to our house while it was under construction so I could use the irrigation system. When I went to bury the pipe after they were done all the pipe cracked when bent--I suspect due to UV exposure. Note I live in southern Florida and the sun is pretty intense and year round. Painting it should help if it will be above ground. I would use a light color, as I have seen dark paint cause excessive expansion of PVC boards in the sun. Kind of like the difference between a concrete dirve in the sun and an black top drive (much hotter). 

If I go this route, I will bury it in dirt and balast--no worries about UV. 

Thanks for the great discussion-I'll book mark this one for sure. 

Matt


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## fsfazekas (Feb 19, 2008)

I wanted to second the comment about painting the PVC pipe where it is exposed to UV. I live in northern California about 20 miles west of Sacramento and I can vouch for the fact that unprotected PVC does deteriorate over time in our climate. This usually takes several years and requires some stress on the PVC - but it does eventually fail. That being said, I am going to be looking very closely at this method for expanding my RR.


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## RGSSJD (Jan 5, 2008)

I started using the gray conduit instead of the white PVC pipe, the conduit is UV protected. The conduit was less expensive when I started building my R.R., but increased past the price of the PVC when the price of metal conduit went through the roof. Not sure how the pricing is today. Did end up painting the uprights anyhow, a few cans of $1.00 a can primer from Walmart solved the problem of the white and gray uprights. Hope this helps.



.


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## maculsay (Jan 2, 2008)

Great thread!!

Has anyone tried using furniture grade PVC pipe? It has 2 layers, the inner layer is regular PVC pipe and the cap layer is finer quality of PVC that is resistant to damage from the sun. It's a little pricey @ $1.54 per linear foot. They also make all the standard PVC type fittings and and a large variety of specialized fittings out of galvonized steel or aluminum.


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## Allegheny (Jan 2, 2008)

I was just at HD and checked the prices on 3/4" and 1" plumbing PVC and PVC conduit. 3/4" was $1.33/10' and $1.12/10' respectively; 1" was $2.03/10' and $1.73/10'. So the PVC conduit has dropped in price in concert with steel EMT. Prices for butt couplings were in a similar ratio. The HD was in Norwood, MA, so your mileage may vary depending on your location.


Incidentally, the PVC conduit is labeled as UV "resistant" not UV "proof." I would imagine you would still need to paint it and the resistance would afford some piece of mind for areas where the paint rubs off, etc. 


Brian


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## RimfireJim (Mar 25, 2009)

Posted By Allegheny on 10 Jul 2009 12:28 PM 
I was just at HD and checked the prices on 3/4" and 1" plumbing PVC and PVC conduit. 3/4" was $1.33/10' and $1.12/10' respectively; 1" was $2.03/10' and $1.73/10'. So the PVC conduit has dropped in price in concert with steel EMT. Prices for butt couplings were in a similar ratio. The HD was in Norwood, MA, so your mileage may vary depending on your location.


Incidentally, the PVC conduit is labeled as UV "resistant" not UV "proof." I would imagine you would still need to paint it and the resistance would afford some piece of mind for areas where the paint rubs off, etc. 


Brian 


Who woulda thunk it? I had always assumed that conduit cost more than pipe, being "electrical grade" _and _lower volume of sales. I've bought each one for its intended purpose, and never had reason to compare the price. Maybe pipe cost more because it is rated for pressure. Thanks for the heads-up on savings some money. Unfortunately, I don't believe HD or Lowes carries PVC conduit in 20' sections, which should make for a little smoother curves and fewer joints to deal with.

I have some painted PVC irrigation pipes that have been in use for years, so I'm totally confident that paint provides adequate UV protection. I wouldn't want to look at the gray of conduit either, so I'd paint it, too. The built in UV resistance is a bonus, like you say.


The paints I've used on the pipe are Painter's Touch Nutmeg and Moss Green (both satin), which, when used together randomly, make a pretty effective camoflage.


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## fsfazekas (Feb 19, 2008)

Just wanted to throw in some pricing info from my local Home Depot here in N. California. This is all schedule 40 PVC pipe - there was a very LIMITED selection of conduit at my store and what was there was not priced. Here goes: 

1" x 10' - $2.17 
3/4" x 10' - $1.41 
3/4" x 20' - $2.92 
1/2" x 10' - $1.10 

FYI...


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## copycats (Jan 4, 2008)

I have tried your method #1 on a test strip 10 feet long supported with treated posts every 2 feet. It seems to be pretty solid. Do you think it will hold up that way ? I just finished it just before dark and did'nt have any time to test an engine on it. The heaviest engine probably will be an Aristo E-8 possibly 2 of them. Thanks.
Dennis


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## Big John (Jan 4, 2008)

I saw your method 2 in an article from Garden Railroad magazine about 12 years ago. I think it was in the Tips and Tricks free phamplet they sent with my first years subscriptions. I am using grey 1/2" PVC conduit and your method 2 for my layout. However I am also using Richard Smith's system of elevated platforms. I just screw down the single lower conduit to the 2x4 cross pieces to form the track layout. That way the conduit is supported along its entire length with the wire mesh that covers the 2x4 framing. If you are not familiar with this just go to Richard Smiths web site and he has details on his elevated frame system. 

When I am happy with the way the track flows I use electrical ties to add the two upper pieces of conduit. After checking everything for level in both directions I screw the two top pieces of conduit into the lower one. I just leave the electrical ties on as they do not get into the way of the track. I don't paint the conduit as it is all burried in soil or balast gravel and is not seen. When I learn how to post pictures I will try to make this easier to understand. My track is just laid on top of the conduit with a sall screw through the tie and into the conduit in the center of each tack section and balasted to keep it in place. I also leave gaps at each track section connection to avoid expansion buckeling. I use 250 aluminum track and run battery RC so I don't have electrical problems with the gaps. I don't do anything different for switches. They are laid on top of the conduit and held in place with a small screw through the ties and into the conduit at each end and then balasted to keep them from moving. 
Big John


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## Dave Ottney (Jan 2, 2008)

I just came across this thread while looking for ideas for an outdoor layout (running inside right now). Does PVC cement work on the conduit? 
How deep should the pipe be in the ground for raised roadbed? I'm in upstate NY where temps vary from below zero to the 90's. 
Thanks for any advice, man this is a brilliant idea. 
Dave


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## RGSSJD (Jan 5, 2008)

Dave

There is a different cement that is made just for the gray conduit pipe, where ever you purchase the pipe they will have the cement. On the R.R. that I built all the conduit is in the ground 3ft, that should be the same for you up there in NY. 



















Ken 
RGSSJD


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## Jerry McColgan (Feb 8, 2008)

For what it is worth I built a layout years ago with 3/4" PVC. I had a great deal of trouble with getting and keeping the top PVC level (trains fall off track that is not level) and eventually I replaced all of it with composite decking. 

In my case (following suggestions at the time) the track was laid directly on the PVC because I had no idea how to get an upper layer that curved with the PVC.

I am not suggesting that PVC cannot work but rather that as they say "the devil is in the details" so if someone does use PVC to be sure to accurately follow directions from someone who has had such a layout up successfully for several years. In my case all the work and materials I put into the PVC project was wasted and a real pain to get rid of.

This is not a recommendation of an alternative - just a suggestion to be careful whatever method is chosen.

Jerry


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## geb (Feb 15, 2008)

Another use for PVC is to form what will be a trestle roadbed. I laid down one end on roadbed and lashed the other end of 15 feet of PVC to the existing bridge. All this is on a grade and curve. Then I lashed each bent to the PVC allowing for decking to be put on later. Once the footings were set I pulled off the PVC and added decking and track. 
Bill


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## RimfireJim (Mar 25, 2009)

Posted By RGSSJD on 01 Oct 2009 06:09 PM 
Dave

There is a different cement that is made just for the gray conduit pipe, where ever you purchase the pipe they will have the cement.

I've used my regular plumbing PVC cement on conduit and it works just fine. Both the plumbing pipe and the conduit are PVC. Oatey's (cement manufacturer) website says "Recommended for ALL grades and types of PVC pipe and fittings, potable water, pressure pipe, gas, conduit and DWV." on all their PVC cement products, whether they are clear, blue or gray.


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## Dave Ottney (Jan 2, 2008)

Thanks for the advice on cement guys. 
Dave


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## TonyLou (Sep 3, 2009)

Dear all everyone, 

Thank you for your great pictures. I saw many pictures that how to connected the PVC pipe standard to the table top. Is it reliable and strudy ? I am also want to doing something similar for my portable layout. I would be very appreciated if anyone of you could send me picture. 

Having fun in garden trains, 
Tony


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## AzRob (Sep 14, 2009)

This is very good info. Anyone have any pictures of the junctions between the lengths of PVC. I am finding it hard to visualize with just the head-on diagram, and I haven't noticed any junctions in the following pictures. I am specifically interested in the Method 2, as I am looking into the best way to put up an elevated track for my steamers...


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## Torby (Jan 2, 2008)

Pardon me for digging up an old thread. 

The idea here is that once you fasten the 3 rather flexible pipes together, they become quite rigid?


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## Torby (Jan 2, 2008)

Must have passed from living [email protected] url(http://www.mylargescale.com/Providers/HtmlEditorProviders/CEHtmlEditorProvider/Load.ashx?type=style&file=SyntaxHighlighter.css);@import url(/providers/htmleditorproviders/cehtmleditorprovider/dnngeneral.css);


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## Pete Thornton (Jan 2, 2008)

The idea here is that once you fasten the 3 rather flexible pipes together, they become quite rigid? 

Torby - simple answer: Yes. Fasten them with pipe glue and they become very rigid. Rog's track handles some very heavy metal locos.


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## Totalwrecker (Feb 26, 2009)

And Torby, you can use the cheaper glue. As noted above there are glues for purpose, but seeing as you won't be dealing with water pressures, use the cheapest PVC glue. 

John


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## Torby (Jan 2, 2008)

Interesting.

I *thought *I was looking at buying a little house with a pretty big yard, but something else has happened and maybe not...


Anybody in the market for an absolutely pristine 2010 Honda Civic VP with 925 miles on it?


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## CliffyJ (Apr 29, 2009)

Hi, I apologise for the late-date barge-in, but this is a key subject for me, as I'm planning my first tracklaying for next spring.

Much of this sounds / looks like the sub-chapter article on "Roadbed from Plastic Pipe" in Schleicher's 'The Large Scale Model Railroading Handbook' (my copy is from 2000). That 3-pipe method really intrigued me, for its ability to arrange things in 3D space and fill in with dirt later. However, I was concerned with the PVC conduit becomming brittle over time. 

From the posts here though, perhaps that not an issue; so believe me, I'm going back to re-evaluating it. I couldn't see your initial pics Bob (they showed up as X's for some reason), but your narrative gives me the idea. Thanks!! Also, thanks to everyone else who posted pics -- I'd no idea that this approach was being so widely used! 

But here's a few comments / questions.

1. About that dirt burial. Let's say you have a PVC-elevated section, about 2' above grade. You come back later, tamp it as best you can, re-pack the next season when it settles, all that. But with hard ground freezes, over time, will the pipes crush or crack? Is the degradation solely due to UV exposure? My guess is yes, and that ground contact isn't the issue. (I think I'm answering my own question, but thanks all for allowing me to think this thru on the air). Comments?

2. Anchoring. I suppose you have to plant the posts below frost line, which is fine with me. I live in Maryland, and my contractor-friend won't be happy until I sink 4' footers for pickin' everything







. But (not really understanding how frost heave really works and affects things) are there any issues with the ground pushing the whole layout up, then letting it down, repeatedly, resulting in unpredicable joints (e.g., in the spring)? 

3. Adhesives. The Schleicher blurb (it was about the method that Bill Baldock had come up with) involved gluing the track directly to the upper pair of pipes. To me, that seems to be asking for trouble if anything gets bumped -- as the adhesives get degraded. But even if a roadbed substrate is introduced in between, with differential expansion / contraction of metal rail vs. plastics, and with simply walking around the track and the ground heaving, won't the adhesives lose the battle? Silicone strongly suggests itself, in my mind... but even that tends to break away. Comments?

4. Pipe Type. Bob, you give great info on schedules / composition options for tighter radii. I need to go down to R4' in some sections, and will have R5' everwhere else. Long story. I was feeling confident about the PVC conduit, as there's a good chance that it's rated for direct burial in various climates. But PEX? And is that the same as CPVC? Bunch of research ahead of me, but that's all good! Any comments?

5. My main question though is about the upper surface. I really didn't like the idea of track being glued right onto the pipes. Instead, I'd so like an impervious, synthetic roadbed material capable of going from elevated to ground, dimensionally expanding at switches and into yards as needed. So what's the "foam" being used in some of the pics? I'd love to use something like that: compliant with grades, easy to sabre-saw, easy to glue (if the adhesive is OK for long term)... Thoughts?

6. Final Suggestion. If all this works, in theory and practice, can a series of diagrams (e.g., cross sections) be come up with? I'll volunteer to the CAD work, if that would be helpful. 

Thanks all for permitting me the long-windedness, and, in advance, for any advice. I'd sure love for this method to work!

===Cliff


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## jfrank (Jan 2, 2008)

Why don't you just use this stuff. It's pvc, already available, easy to use and works great. I use it and highly recommend it. I wouldn't use anything else. 

http://www.gardenrailwayproducts.com/howdoi.html


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## armorsmith (Jun 1, 2008)

Cliffy, 

Here goes from my 'for what it's worth' department.... 

1) The club I am a member of used the PVC spline ladder method however the posts are still vertical 2" Sch 40 pipe. All of our posts are set in concrete footings to minimize movement. All of our layout was installed using a contractors transit to insure that the sub-roadbed was true and level. Our layout is 'back filled' to the top of the spline ladder with sandy red clay mix. We tamped and water settled both with natures sprinkler and the ones we installed. Our layout is in the panhandle of Florida, so generally speaking we don't have to worry about freezing although we do occasionally see temps in the 20's. Now to answer the question. The degradation I have witnessed has not been from UV where the pipe has remained below the surface of the back fill. My concern is with the water that collects inside the vertical pipes from the sprinklers and rain. A hard freeze with water in the pipes can crack them. 

2) Being a 'Damned Yankee' from New Jersey, I can tell you without hesitation if you set your posts in concrete and below the frost line for your area, you should not experience any lifting of the posts from frost. As for the layout staying level, for all the upfront effort to assure level and true, after two years in operation our track work pretty much resembles the CSX main line that passes right by our location. We have all the dips and rolls of the prototype. 

3) No experience, we didn't us any adhesives of any kind on the sub roadbed. Track is a combination of anchored occasionally with a screw here or there and free floating. 

4) Can't speak to the pipe, but the 1/2" x 1-1/2" splines we used formed easily for our minimum 10'-0" diameter curves. All joints were made mechanically with screws or bolts depending on location. 

5) Based upon my experience with our layout, I would not recommend adhesives of any kind for attaching the track to the sub roadbed. Differential expansion and contraction will definitely give you problems. Reference your own thread on track expansion. 

6) No comment. 

Bob C.


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## CliffyJ (Apr 29, 2009)

Bob, 

Your comments are very instructive. Assuming your PVC splines are boards (and not pipes), the method you describe is very similar to the one I'm increasingly in favor of, and that has been recommended by Bob Hyman; http://www.mylargescale.com/Communi...fault.aspx

In an article elsewhere (http://home.comcast.net/~therealms/roadbed.htm), pipe caps were used between the splines, which I believe would help in the important filling / freezing issue you raise. 

I agree with your emphasis on setting the posts in concrete, and using a larger pipe size. All makes a lot of sense.

I'm sort of surprised that you can bend 1/2" thick PVC to 5' radius; I'll have to try it! What did you use for spacers between splines? More PVC board?

Thanks very much,

Cliff


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## Torby (Jan 2, 2008)

The split-jaw stuff is really nice, but outside the budget. Shoot, having a place to put a garden is yet again out of budget itself.


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## CliffyJ (Apr 29, 2009)

Roger that Torby, that split-jaw product line looks great. 
But how does it hold up, with frost heave? Using 3/4" or 1" pipe posts, and with the ground pushing up against the UHMW roadbed, what breaks first? Or do the posts just pull up?


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## armorsmith (Jun 1, 2008)

Cliff, 

Yes, we used 2 3/8" lg pieces of the spline for the spacers. We used stainless steel sheet metal screws for attachment, they were driven both with and without pre-drill and I do not know of any real performance differences in methodology. 

The half inch thickness is pretty flexible. L\Keep in mind that our sub-roadbed was made in the summer months in northwest Florida, so I believe the warmer temps helped. I do admit that ALL PVC material, unless supportd very frequently will sag over time (maybe not short term with heavy weight, but long term), ours has. My opinion, it adds to thr realism. Ihave never seen prototype trackage as good as we try to generate. 

Stay safe and warm this evening. I am camped ut in Charlotte, NC for business training. They are expecting 2-6" of snow tomorro, changing over to sleet and freezing rain tomorrow evening into Tuesday mornong. Just peachy!!! 

Bob C.


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## TrotFox (Feb 15, 2008)

Cliff, 

I've got aluminum code 250 rail and split-jaws. The clamps are stiffer than the track. The only suggestion I might make is to put some sort of anti-sieze lube on the screws before planting the track. Otherwise they tent to... well, sieze.  

Trot, the unstuck, fox... ;]


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## CliffyJ (Apr 29, 2009)

Thanks for the info on the pvc boards Bob. It's sounding like a great alternative to cedar for the ladder. 

I'm ok with sag, as long as it isn't enough to derail things; is the amount of sag you refer to 'in the noise," or something more -- e.g., requiring you to put your rail joints somewhere other than at the tops of posts? I suppose not.

Yeah, it's sounding quite nasty down there, weather-wise. I'm in Maryland, so we'll get some of it tomorrow (Tuesday) as well. My advice: hunker down in the hotel, skip the training, and plan your next expansion!


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## armorsmith (Jun 1, 2008)

Clif, 

To use you terminology, it's in the noise. Does not create any real issues, just IMHO looks prototypical. 

Bob C.


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