# Loading specifications for a ladder system



## Randy Stone (Jan 2, 2008)

I see a lot of layouts using the ladder system, but unless I have over looked them, I've never seen any specifications regarding the loading of the ladder and the posts.

Specs as to what formula was used to determine what size ladder system was to be used.

In building layout tables inside, I have always used 2x4s and 3/4" particle board. 

People said it was overkill, But I knew I could climb up on the table and walk on it without fear of it falling down.

But with the ladder system, I don't know what overkill is. 

I have to assume there is no wall in the back yard to help stabilize the ladder. 

So, Let's assume you have a USAT Diecast Big Boy and a string of cars in tow. 

If you want to set your supports at say 96 inch intervals, what size ladder side rails do you need?

I know you have to consider, the locomotive, freight cars, the track, ballast and some scenery.

If you want to run a double track where two Big Boys might cross the 96" span at the same time, how much bigger will the side rails need to be?

I assume the side rails don't need to be double the size of the single track.

As for post, I've seen 1 1/2 inch PVC pipe used for posts and I've seen wooden posts.

Has anyone figured out what size of PVC needs to be used on an elevated layout?

In my case, I'm looking at my track being 36" above ground level and possible climbing high enough to cross over it's self.

With me being in Florida and the back yard holding water when it rains, I'm looking at having to use PVC pipe for support posts.

How about it Engineers, is the guidlines we can use when designing a ladder system without having to hire a Structural Engineer?


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## Mike Reilley (Jan 2, 2008)

You're 96" span...is like...WAY TOO FREAKIN' BIG. Think of 18" between posts...maybe 24". Then remember....ladder roadbed is buried...so the ladder is actually sitting on the ground. And many folks put gravel around and under the ladder too to improve drainage so that the ladder wood doesn't sit in water and rot. The purpose of the ladder roadbed is to provide a firm base for supporting the track that won't erode. If you cover the top of the ladder with window screen before you put the track on, you also don't have to re-ballast as often...and it helps keep the weeds down. 

Now...if you want the track 36" up in the air, you're NOT talking about ladder roadbed. Up that high, PVC won't work well IMHO, unless you fill it with slurry to make it very rigid...and, 1.5" PVC (which I use) warps in the heat when it's unsupported (that's why you'd have to slurry it)...so keeping it vertical so the roadbed is horizontal becomes a challenge.. I've got ladder roadbed going in now...and when it's 1' high with 1' of 1.5" PVC in the ground, it's wobbly...and keeping the ladder horizontal side to side is one of the challenges. It'll firm up when I bury it.


Me...I'd be looking at galvanized steel posts set in concrete footings as the piers spaced every 4 or 5 feet. I think I recall you complaining about termites. Then I'd build a wood structure from pier to pier...or use L angle like Marty did for his steam track.


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## armorsmith (Jun 1, 2008)

Randy, 

Mike is absolutely correct, 96" is dreaming. The system I have come up with (untested) for my line in the panhandle of Florida is as follows: 

Posts will be 3" schedule 40 PVC up to about 12" below track level. On top of the 3" pipe will be a 3" x 2" reducer with the 2" size bored clean through (2-3/8" hole saw). 2" schedule 40 PVC will make the last approximately 12" of the rise. The vertical alignment will be held in place with a SS hose clamp on the 2" pipe. Posts will be no greater than 24" on center. The ladder/spline portion will be pressure treated lumber, 1/2" x 1-1/2" (ripped on my table saw from 2 by material - and yes I know the dangers of pt lumber saw dust). These will be screwed to the 2" riser with SS sheet metal screws. There will also be spacer blocks located between the posts at the half way point. I currently do not plan to pour concrete in the posts or around the bottom of the post, but that could change when construction commences. 

Track laid on the ladder will be as follows to allow for expansion in the Florida sun: 

All Aristo curved track is 20 foot circles. Two sections of track will be hard coupled with Hillman/Split Jaw rail clamps. The tie sections next to the rail clamps will remain screwed t the rails. All other tie sections will have the screws removed to allow the rail to mover freely along the track center line. Tie sections will be located and screwed to the ladder. A little math at the time of installation for expansion/contraction based on the current RAIL temperature (I have infra red thermometer read 165 degrees in summer sun) will determine the GAP to the next track section. Similar precess for straights. Gapped joints will use a standard Aristo rail joiner, and will have a 14AWG wire jumper soldered across the joint (loop the wire to allow motion without restriction). 

My club used the PVC material for the spline sections and I believe the PT will be more stable and stronger. I have not started my track laying yet (hopefully toward fall of this year), but have spent a lot of reading time here and on LSC, along with my experience with the club layout. 

Good luck Randy. 

Bob C.


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## wchasr (Jan 2, 2008)

Randy, 
I know i've seen some of the original Ladder style setup that were eleveated lines simply painted and not buried BUT selection of materials becomes VERY important then. Genereally most of us that have considered or are using the ladder style have economized on the PVC trim board of some sort for the ladder sides,where as the original design used a slightly more sturctural form of deck board or even wood. NONE of the examples I've seen use an 8 foot spacing unless they are more of a "Port Orford Coast" type of thing where the raised seciton is more of a deck structure built from and with decking materials. Or on one of the many raised storage barns that have become more prevalent of late. Even then I think they are spacing no more than 4 foot apart with LOTS of sturdy bracing under the decking and it is no longer a "ladder" style of support. 

Chas


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## Randy Stone (Jan 2, 2008)

Thanks for the replys. 

Where I have seen the 8' spacing was on live steam layouts. It was a double track setup using what. Looked like 4x4 post and 2x4s to support a box frame that I called a ladder. The box looked to be made out of 1x6 boards. 

But my main question was what formula doyou use to determine the size of support material to use? 

Surely the systems are not all based on guess work.


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## armorsmith (Jun 1, 2008)

Randy, 

S - Scientific 
W - Wild 
A - Ass 
G - Guess 

Mine is entirely imperical based on my experience with the results of the methodology the club I belong to used. We used 2" pipe supports on roughly 24" centers (max height about 4 foot). At the highest, they were not real stable, hence forth my decision to go to 3" pipe with a 2" stub on top for the spline spacing. The club used the 1/2 x 1-1/2" PVC molding material available at Lowes/Home Depot locally. Until the backfull was fully supporting the spline member the sag was noticeable whenever one of the larger locomotives was being run, especially in the hotter weather. My choice to go to ripped down 2 by material is solely based on the wood being stiffer than the PVC material and less prone to the affects of temperature variations than the PVC, and if I see any sagging during preliminary operation I can laminate an additional spline member in place. As for the 3" pipe, I weigh in at about 200 lbs and have hung in the middle of a 10 foot length supported only on the ends. I believe it to be strong enough to hold up my railroad. 

I am sure if I chatted with one of my engineer co-workers I/we could develop a formula, but is it really worth it? For what we are doing, I think that when in doubt, throw more material at it. If you are saying that the system you have seen is 2 parallel 1x6 boards on edge with tie blocking in between, you are effectively talking about a plate girder. Sure that will span 8 feet. I am concerned about the thermal expansion of the rail, I have seen what thermal expansion can do and fully intend to compensate for it. 

Bob C.


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## Randy Stone (Jan 2, 2008)

Thanks Bob 

I like the SWAG. That pretty much sums up my design criteria for most all things done around the house. 

I really had hoped one of the many engineers that are supposed to frequent this site would be a structural engineer and provide some useful information not just for me but everyone. As it appears, this site is mostly made up of the "sound the whistle" type engineers. Not all bad for a train site for sure. 

So, I think I'll try two parellel 2 inch Scedule 40 PVC pipes and if it seems too wobbly, I'll see how 3 inch works. I wonder if filling the PVC with sand will add any stabelization to the system. One nice thing about working with sand is the ease of digging a hole.


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## Trains (Jan 2, 2008)

Randy,

I used 1 1/2" pvc pipe, set 30" in the ground. My tallest one is about 24". I set them every two feet apart.
I used 1x2 pvc plastic house trim for the ladder. Marty had his USA trains bigboy running on it. Held up very
good. If I was to go higher then two feet on the poles, I would go to a bigger pipe.

Don


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## Randy Stone (Jan 2, 2008)

Sounds good Don 

Here is the thread I seen with the box girders set on what looks like 8 ft centers 

http://www.mylargescale.com/Community/Forums/tabid/56/aff/9/aft/119791/afv/topic/Default.aspx


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## Trains (Jan 2, 2008)

Randy,

I seen that a while back, great idea but I'm not to keen on CCA wood. I had some around the house and it warped 
real bad. My ladder has been out now for three years with no problems, OH one problem the squirrels are eat the landscape
fabric. So I'm out there redoing all the landscape.


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## Polaris1 (Jan 22, 2010)

Randy, I'm building an elevated 340 ft curved ladder G RR based upon the Paul Race (Ohio) Internet guidelines. I think you must differenciate 
between the straight segment multitrack ladder design and a singe track curved ladder design. The PVC post locations on about 2 ft centers 
defines the RR track curvature of the 2nd option. Here 8 inch increment spacer blocks (same width as PVC pipes) forces/ locks in the curves via the 2 flexible 
siderails. The support width of 2 (3/4" inch wide ripped rails) plus the spacer block is the supporting width surface for the 45 mm single track. 
In short, the Curved ladder fabrication technique lends it self to curvy track by merely mislocating a PVC support post. 
Pure milk jug plastic is too soft for ripped rails...... Consider BearBoard (Milk Jugs & crushed rock from Elgin. IL) for a more rigid flexibility. 

The straight segment ladder fabrication technique is a whole different "ball game" where 4x4s, big pipe posts & wood play a role.


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## wchasr (Jan 2, 2008)

Randy, 
As "Polaris" has said when you jump to the wood and straight segment fabrication there are MANY calculators online that will tell you EXACTLY what you need. For a human walking on a deck. You are essentially building a small deck and as such should build to your local building code requirements. Or at least closely. When I was wondering about pool decks I "googled" and found a plethora and multitude and a whole lot of information about building decks available online. Still haven't built that pool deck though. Once you've jumped to this style of fabrication I do not consider it a ladder roadbed anymore, but that is me. 

Chas


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## jake3404 (Dec 3, 2010)

Randy, 

I'm a Mining Engineer but had to take all that structural stuff. An 8' span requires a 2 x 6 dimension lumber under normal loading conditions. That is a minimum, if I was going to build a deck with 8' spans between the post I'd probably elect to go with a 2 x 10. You live in a rather humid part of the country and that moisture will cause the wood to eventually sag. When it comes to our railroads sag is a "four" letter word. Now you can combat it with methods like you described, using a box structure to spread the weight of the load will reduce the sag, but it is still possible. 

Like Marty described and what I am using to make my ladder roadbed is small dimension PVC pipe and PVC trimboard. I'm only using 3/4" diameter pipe and there have been those who say I'm going too small. But my roadbed is completely buried. The pipe is to function as an anchor to keep the roadbed in the ground. (You can see my thread in this section for my reasoning "building the DBH&W"). I'm using PVC because my ladder is buried and I dont want rot.

I think what your looking at doing is more suited for a "Deck" roadbed. If there is problems with termites and rot, then look at materials that are resistant to that. Many good ideas have already been said. The so-called forumals that you seek are based on building an actual deck. There are many sites on the web that can help you there. You need to know what span you plan to use, the expected MAXIMUM load, the dimension of lumber you want to use and go from there. 

If you use dimension lumber, my suggestion is to not exceed 4' between spans. The size of the posts is relative to the stability that you need. The compression strength is much higher then you'll ever put on the weight of the post. Look for a post that is large enough to reduce the "sway" of the deck. 4 x 4 work real well for this.


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## armorsmith (Jun 1, 2008)

Randy, Jake, et al 

I suppose I should have clarified that my road bed will be in the open air for a good period of time prior to the building up of scenery (dirt) beneath it. It is also my intention to maintain the dirt level at least 1/2 below the bottom of the splines and use fine gravel (whatever it is called in your neck of the woods) up to the road bed. As I mentioned above, the club I belong to used 2" pipe posts with 1/2" x 1-1/2" PVC spline material and before the back fill was completed, noticeable sagging between posts was evident on hotter summer days. I live in the panhandle of Florida, a good bit north of Randy, so I am sure that heat on the PVC will be an item he will consider. 

I also realize that the curvature will also play a big part in the methodology you are going to use. All my curves are 20 foot diameter, so I have not issue forming PPT 1/2 x 1-1/2 material to that radius. I am sure that tighter radii will create their own difficulties, where the PPT will not be a good option (unless steam bent - even I don't want to go there). I am also investigating some options to make the spacing of the 3" posts greater where the height is above 24" (on the straights only). Not far enough along to be sure it will work on mine yet. 

Bob C.


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## Randy Stone (Jan 2, 2008)

Guys, the information is starting to flow which is what I was hoping for. 

Not just for me but anyone considering an elevated layout. 

My first thought was to use a cement block wall to support my railroad. 

While it would give a super strong foundation, the cost would be very high. 

Up north there was always used block you could get, but here in Central Florida, there isn't much chance in finding used blocks. 

so, I'm exploring various types of supporting structure. 

Wood is relativly cheap, but it's heavy and it rots. 

Anything bigger than 1 1/2 PVC is expensive. 

I can't depend on having dirt fill under the road bed before trains are running. 

So, the search goes on. 

Thankis for the replys and all the info.


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## Mike Reilley (Jan 2, 2008)

Now that I understand what you're trying to do...go to Home Depot and look at their galvanized and coated steel posts. They're down at the end where the lumber is. Here's a link to a little one that's on line... Spade post .You just pound those into the ground and attach your woodwork to support the table. These are cheap, and you can install em as you go. Using these on four corners of a box structure would be plenty strong.


Now...you've got sand for soil...so I'd be concerned with those coated steel posts...because they only go 1' into the ground...and that's NOT DEEP if you are concerned about hurricane winds lifting your layout up..and breaking it. So you might consider using galvanized pipe fence posts. This is what I use to build 5' tall fences here. Each post is a 2.5" diameter galvanized steel pipe. Home Depot sells them in 6' and 7' lengths...and you just pound them into the ground with a tool (Fence post pounder). Here, the posts cost $13.96 (just bought some for a fence). 



So, I'd get the 6'ers...and pound em 3' into the ground...and attach the woodwork to them by drilling holes in and bolting it on. You'd need one of these posts ever 8' or so. These puppies are STRONG. The fences I've put in have been in for 15 years so far...and have lived through many Santa Ana winds. If you want em stronger...put slurry inside em.
http://vimeo.com/moogaloop.swf?clip...byline=0&show_portrait=0&color=00ADEF&fullscr


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## jake3404 (Dec 3, 2010)

Mike, 

Wouldn't it better to put those posts about every 4 ft to reduce the risk of sag? 

I wonder how long you plan on having the layout...I also dont know how the weather effects the wood down there. But perhaps you can started with a pressure treated wood deck, and as it rots out switch to a different product.

I think you could use 1 1/2" PVC trimboard, but your going to want to support it every 2 ft.

An idea to cut down on cost: Use the PVC trimboard. For supports use a thinker more substantial post every other post, then use a 2" PVC pipe post for the in between. I think the stability would still be pretty good.


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## Russell Rutalj (Dec 7, 2010)

For the last 3 months i have been working on a elevated railroad in back yard. It is about 43 inches high , The posts are PVC 4 inches square. 1/8 in thick wall.Concreted into the ground about 12 inches. I used pressure treated 1 x 6 for the base and 2 x 4 for the ladders.


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## Randy Stone (Jan 2, 2008)

Hi Russel 

That looks really good. 

Are you planning a single track or dual track on the section closest to the camera? 

I hadn't thought of using square tubing, but that should be more ridged than round. 

Please keep us updated on your progress. 

Randy


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## Russell Rutalj (Dec 7, 2010)

Posted By rlvette on 08 Jun 2011 06:31 PM 
Hi Russel 

That looks really good. 

Are you planning a single track or dual track on the section closest to the camera? 

I hadn't thought of using square tubing, but that should be more ridged than round. 

Please keep us updated on your progress. 

Randy 

Hi Randy _ plan to run a single track around the 160 feet , but in the wide area there will be a siding of 30 feet. I bought the 4x4 PVC posts at Lowes because they were 100 inches. They cost about $23.00 each but i cut them in half.and put 12 inches into the ground. Post hole cement works great.About a half a bag each hole. I used my chop saw to cut them in two. it worked great. I used a small level so that they would be straight. I spaced them every 5 feet, but adjusted them a little going around my 90 inch curve. I used a 1x6 pressure treated wood 12 inches long on the top of the posts. Right angle brackets hold it in place. All the wood is painted first with copper green wood preservative , then painted with a colored exteror paint. I have the rail system done and i am waiting for track, which will come later this month._


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## wchasr (Jan 2, 2008)

Mike Reilly, 
I think the pricing "might" be better at Tractor Supply Stores on the Spade posts? 

Chas


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## rmcintir (Apr 24, 2009)

I've built the Old Salt n' Mangrove elevated as the saltwater can come up over 3 feet in the back yard during a storm. Here are some links to pictures of the latest expansion. I've used 3" PVC pounded directly into the dirt about 2 feet. 3" - 2" reducer with 2" between the ladder rails. The rails are made of 2 1/2" x 3/4" TuffBoard from Home Depot. I have one location where I will have a longer run across a gate using a removable section to the left of the first picture. I will use wider TuffBoard there for rigidity. My typical span is about 4 feet. I use Trex blocks as rungs of the ladder. Everything is synthetic. I can pound the 3" PVC directly into the ground using a post driver from Norther Equipment. It fits perfectly. My locos are pretty heavy, all battery powered. No problems with the spans or with movement of the 3" posts. No fill in the posts either. That is an option if it becomes a problem. The track tends to self support the more you have in place.

Expansion underway: 


View looking north: 


View of the north loop. The siding isn't located there anymore but on the far right side of the picture now: 
 


Here is a real early picture of construction. I don't have the blocks as closely spaced now:


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## armorsmith (Jun 1, 2008)

Russ, 

Other than using the 3/4 x 2-1/2 tuffboard, you have nailed my concept almost perfectly. I plan to use Pressure treated 1/2:" x 1-1/2" ripped from 2" by material I have left over from other projects.The other difference will be to bore the reducer through on the 2" pipe )2-3/8" dia hole saw) so the 2" can slide up and down for vertical adjustment and make the 2" pipe a bit longer. I will fix the vertical with a Stainless Steel hose clamp during construction and fix the height later with Stainless Steel screws. As for construction schedule, I have a fencing project and a bunch of retaining walls to put in place before the railroad can begin. I hope to start construction late summer, early fall. 

Your railroad looks great and your appears to substantiate my SWAG design concept. Thanks for posting pics. 

Bob C.


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## rmcintir (Apr 24, 2009)

Bob, 

I saw your post and figured you'd like the pictures. I was going to make the 2" PVC adjustable but changed my mind. I doubt I will lift any of the existing track much higher. All that would be required is removal of the 4" long 2" PVC and replacing it with a longer section. I use a screw through the reducer to secure it. Nothing is glued, everything is screwed together. 

BTW, the TuffBoard is very bendable. I made the expansion over a weekend. All is assembled in the air at height. 

Looking forward to your pictures when you finish all the prep. I built my retaining wall after the loop was there. 

russ


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## York Santa Fe (Feb 2, 2011)

Having come from a former engineer and builder background and having 800 feet of ladder type system made from HDPE material that was installed over 5 years ago I would like to made a couple of comments in regards to types of materials. The trade name TREX seems to be used by the general public to cover a lot of different products. Some of these so called HDPE products may contain a high percentage of wood fiber and after a period of time will tend to swell and develop mold especially when the product is cut into smaller pieces. 

In another area members should be careful when cutting treated lumber into smaller dimensions for several reasons. First, treated dimensional normally has a reasonable number of knots and when cut into smaller pieces the knots will decrease the structural strength of a span. Second, primarily due to the knots, these pieces will tend to badly twist and warp and it may be difficult to keep straight after cutting and also from sagging when exposed to sunlight which tends dry out the wood even more then first purchased. 

On a different note, there are several advantages to using HDPE lumber and also several disadvantages in addition to it being rather expensive. On the advantage side is that is it rot resistant and will last a long time in the elements, will not warp or twist and is easy to cut to name a few. The disadvantages are that it is not a good structural material and will need to be supported in most ladder system about every two feet. It also has a coefficient of expansion three times that of brass or stainless track and long straight runs much over 10-15 feet will tend to buckle or break ties if the track is tightly secured to the ladder system. I have found in my case that any of the straight track over the 10-15 foot length now has a curve in it and in other cases has broken the tie where it was secured. Using several pieces of curved track every so often and letting the track more or less float on the ladder will cut down on the expansion and side over lapping problems. 

Another problem, I have recently noticed, is that on curves the expansion difference between the inner and outer HDPE runner lengths will cause the curves to develop a banking (leaning) problem since the outer runner expands more than the inner runner due to its longer length. This banking works well on prototype trains but I have found that the two rails, when level from side to side, works much better. 

I think that many of us, having had previous model trains, that were only run inside on level platforms never had to deal with thermal expansion, frost heaving, corrosion and other weather related elements. These problems, particularly in areas with wide temperature swings, salt water air and rain and frost can cut into the enjoyment of modeling G gauge trains. 

In my opinion a ladder system offers many advantages over other roadbed systems for several reasons. Using a table saw it can be constructed very quick and does not require labor intensive trenching and filling. It can also be installed over terrain that is not level utilizing a variety of support systems. It is pretty much maintenance free, can be readily expanded, has no washout problems, can be elevated, and can easily be adjusted and modified. 

Ralph


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## rmcintir (Apr 24, 2009)

I misspelled the material I used earlier. It is actually TUF Board from Veranda. It is made of PVC and designed as trim board for the outside of homes. It seems to be very dimensionally stable for its intended purpose on homes as well as under my track. For the rungs I tried a cheaper decking material for the rungs. I think it was also a Veranda product, a gray deck board. It had a lot of wood fiber within. It split, and broke apart like paper. I went back to real Trex which is extremely dense. While it may have quite a bit of wood in it it is MUCH more stable and holds the ladder curves well. I don't worry about the Trex expanding or contracting since the blocks are only about 2" square. You have many good words of wisdom Ralph! Thank goodness I don't have to worry about frost heave in Florida!


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## armorsmith (Jun 1, 2008)

Ralph, 

The extreme expansion and contraction of the plastic materials is precisely why I am gong with PT material for the splines. As for attachment of the track, I have also addressed that issue. I will be joining two sections of track with a 'Split Jaw" style connector. The two tie sections adjacent to the rigid connection will remain screwed to the rail, all other tie strips will have the screws removed. Once laid on the ladder, the tie strips will be positioned and all will be screwed to the ladder. Depending on the temperature on the day I am installing the track I will gap the next two track section. This will allow the rail to expand in the ties without damaging the ties. Provided I make sure to leave sufficient gap to accept the expansion of the two adjacent rail sections it will be almost as good as just floating the track on ballast as the prototype does. Electrical conductivity will be assured by soldering 14 ga. jumper wires around each expansion joint on the layout. This will be time consuming, but I believe it will cut down on maintenance considerably (this based on reading posts on this and other forums). The tough part is maintaining alignment while allowing the differential thermal expansion of the various material we use. 

I was surprised that you didn't mention in the detrimental column for ripped PT lumber the known health hazard of the saw dust and breathing it. I have a good dust collection system on my saw, can move it outdoors, and plan to have a breeze at my back aided by a small box fan. 

Thanks for the informative comments on "TREX" type materials. I knew they had some draw backs, but you helped define them. 

Russ, 

Do you know if I can purchase the post driver at Harbor Freight? I don't have a Northern near me. 

Bob C.


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## rmcintir (Apr 24, 2009)

They didn't have one at Harbor Freight. You can buy from Northern online. Here is a link: 
http://www.northerntool.com/shop/tools/product_988888_988888 

If you were a little closer you could borrow it. 

russ


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## Randy Stone (Jan 2, 2008)

Russ 

That is quite impressive. 

I like it a lot. 

Randy


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