# Aluminum FlexTrack Installation



## BuswayBob (Jun 22, 2012)

Am awaiting the arrival of 100+ft of Narrow Gage code 250 aluminum flex track for outdoor installation. Questions about installation: 1) I have already installed solid road bed the entire length including in-ground tunnel. How often should I attach track to solid roadbed? 2) in tunnel, I am thinking of tying track joints together with some sort of wire tie to prevent any possibility of separation . Is this a good idea? I will initially be running battery with hope of going to steam eventually.


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## steamlogger (Jan 2, 2008)

All the track on the ground in this photo is not secured to the ground. 








It is Llagas Creek code 250 AL with about 10' radius. While this track is less than 1 year old I had track that was just in chips and dust (stone) for about 15 years with no problem.


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## Bob in Kalamazoo (Apr 2, 2009)

Wow Robb, does that ever look different from when I last saw it. I guess that was back in about June of 2011. I've got to get up there again some day. By the way, my 0-4-0 steamer has been converted and is running again. Thanks for stopping by back in August and giving me some help.
Bob


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## Pete Thornton (Jan 2, 2008)

How often should I attach track to solid roadbed? 2) in tunnel, I am thinking of tying track joints together with some sort of wire tie to prevent any possibility of separation . Is this a good idea? 
If you go and search this site for 'outdoor track laying' [ google "site:mylargescale.com outdoor track laying" ] you will find lots of discussions on that topic, including "How to lay down track...float or anchor?" http://www.mylargescale.com/Community/Forums/tabid/56/afv/topic/aff/23/aft/112993/Default.aspx . My track was all floating. 

Soldering or screwing the joints would be better than wire ties - but in any case, do stop them separating! 

My tunnel was straight, and I had a piece of treated wood as a track base and wooden strips along the sides to stop the track floating too far towards the sides of the tunnel.


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## armorsmith (Jun 1, 2008)

Bob, 

Aluminum has the largest coefficient of expansion of all the available track materials, meaning temperature has the greatest effect on this type of track. You don;t mention your location so I will use mine as an example. 

I live in the panhandle of Florida, and our total temperature range is typically between 20 degrees on the low side and 100 degrees on the high side ambient. Empirically I have measured 145 degrees on brass rail. The coefficient of expansion for aluminum is .0000123 inches per inch of length per degree of temperature rise. Therefore using your track length of 100 feet (1200 inches) and my total temperature rise of 125 degrees (145 rail temp minum 20 low ambient) the total thermal expansion is .0000123 times 1200 times 125 or 1.845 inches total. 

You will need to in some fashion allow for that growth. You will find many differing opinions how to accomplish this. My intent is to bring this issue to the forefront because it is far easier to compensate for the expansion during the planning stage than to correct it later. 

Happy Railroading and welcome aboard! 

Bob C.


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## Totalwrecker (Feb 26, 2009)

From my observation with SS track in an oval layout. 
The whole oval grew and shrank, so Bob C.'s 1.85" linear was divided by the 4 sides which resulted in less than a half inch of added size to the footprint. 2 sides grew less than a half inch each side, 1/4" at each corner. One corner of my layout floated on a trestle. I had added a third stringer atop the bents so that when hot; the outside rail was over a stringer, likewise when cold the inner rail was over a stringer. The 3rd guy was in the middle to help support the plastic ties. I watched the growth there. 

I think brass rail will get warmer faster due to the warm yellow color, yet the rail does get hotter than ambient temps. The radient sun keeps adding heat.... 

I strongly suggest securing the rail ends together, when expanding all the rails push against each other, but when cooling it's possible for one / some rail(s) to shrink faster than others and pull out of the joiners. My track has screws through joiners that does the trick. 

John


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## Jerry Barnes (Jan 2, 2008)

Hillman's has an expansion joint for code 250 rail, maybe for 332 also. Rails slide, allowing expansion/contraction.


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## Greg Elmassian (Jan 3, 2008)

I prefer the expansion "tracks" by split jaw when you have real problems. They can move a lot and will help keep out kinks and huge gaps. 

Greg


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## armorsmith (Jun 1, 2008)

John, 

My example was to demonstrate that amount aluminum will grow. Yes, that is the total growth based on the numbers presented and assumed to be in a straight line. Longer track, bigger expansion. Higher temperature differential, bigger expansion. If the layout has long straights the expansion can be a major issue, especially if one tries to 'nail the track down'. As I said, there are multiple methods to deal with expansion, just don't ignore it. I have a theory I am going to try as soon as I can get some track down, but until I test it for a year or so I don't want to say too much. Logic and garden railroading don't always go hand in hand. 

Bob C.


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## Totalwrecker (Feb 26, 2009)

Yes Bob, linear is different and everybody's milage may vary. 
I assumed an oval/round with his 100' of track as they are popular starter shapes. Plus he wants to run Live Steam.... I've never heard of a 100' tangent LS track. 
A 1.85" expansion/contraction can sound dangerous, but not so much as my example showed... 
It was also a suggestion to not tie the track down and to allow for some shape shifting. The curved trestle was engineered for expansion of floating track. Worked fine for 6 years. 

I'll be interested in your theory and study when your time permis. 

One size doesn't always fit all in garden railroading... 
I'm in sunny S. Az., I've seen expansion, happily surprised the more complex arc/wye/reverse loop had no kinks. 

John C.


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## armorsmith (Jun 1, 2008)

John, 

The theory is simple. Basic description as follows, working with 5 foot straights for the purpose of the description. 

Connect two 5 foot sections together with 'Hillman' - 'Split Jaw' or whatever your favorite rigid rail clamp happens to be. Next remove all the screws securing the tie strips to the rail, except the two tie strips directly adjacent to and on each side of the rial clamp. My intent is to tape the tie strip to the rial to maintain position. Secure all the tie strips to the sub road bed (I will be using a homemade ladder system of PVC pipe risers and second hand PT ripped into 1/2 x 1 1/2 strips with blocking at 9" C/C. The theory says that for each 10 feet of track, the thermal expansion will go 50% on each side of the rigid rail clamp, the rail clamp being the anchor by virtue of the adjacent tie strips remaining attached to the rial. Standard slip joiners will be used on each end to allow the movement of the rail. The next 10 foot section will be done the same way, with an allowance somewhere between a dime and a quarter gap between sections. Conductivity will be via a looped jumper over each sliding joint. All my mainline curves will be 20 foot diameter, so I am anticipating a similar joint arrangement there as well. I am not too sure how the rial will slide in the curved tie strips, for me that is the 'unknown' value. 

For aluminum rail, based on the temperature values stated above, and a 10 foot length (120 inches), total expansion for the single length would be 0.21402 inches (about 7/32 inch). That is what each gap needs to be for aluminum. Brass rail co efficient of expansion is slightly less at 0.0000104 inches per inch of length per degree of temperature differential. The total gap for brass would be 0.18096 inches (about 3/16 inches). These numbers are worst case scenarios but are none the less real world. Gaping is a bit of an art form in that the gap needs to be determined at the time of installation and using the differential between current ambient and maximum expected temperature for the calculation. For discussion, lets say it is 85 degrees ambient when I am installing the track. The delta is now only 80 degrees. So for brass, coefficient 0.0000104 times 80 degrees times 120 inches, the gap needs to be 0.09984 inches or about 1/10 of an inch. This also assumes that the track has been outside and normalized at the given ambient temperature. 

Thermal expansion can be calculated and compensated for, especially if you have long straight runs, or are in a confined area. My club has a 70 foot straight run on one side. See the areal pic on the home page www.ecgrc.com. Some serious lessons have been learned from that layout. The hardest was that thermal expansion of the track will not be denied. After the first year of two we replaced several 5 foot straights, and at least one had a vertical kink. The curved areas were a bit easier to remedy track issues simply be removing screws and allowing the track to float. I was later decided to purchase expansion sections which have been strategically located about the layout which have remedied almost all of our expansion related issues. 

Bob C.


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## SD90WLMT (Feb 16, 2010)

Well, I have to say your idea Bob matches my intentions on My layout. But, I will not be running track power so I do not need wire jumpers. And I plan to leave slip joints at each rail end, thus allowing a minimal gap at ALL rail joints, and yes - even using the idea of thermal compensation during installation to calculate the gap based on seasonal installation needs. Cooler months need more gap... 

I followed gaps in place, and so far have not found that much give and take in the rail...using a dig mic to measure a floating gap... in place from a cool 10' to a HOT 95' over a years time.. 
I suspect - hopefully - that some is made up for by the simultaneous expansion of the materials used to build the road bed surface, which ironically would help keep gaps to a minimum... 

The rail will expand in heat, 
So too will the road bed materials... 
The interaction of them together will be the cause of any gap changes overall.. 

Dirk - DMS Ry.


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## jfrank (Jan 2, 2008)

Here is how I did it with aluminum flex. To lay your curves, first clamp two of the six foot sections together, then lay the curve. Lay the curves first. This way you do not have slip joints in the bend of the curve. In the tunnel, use rail clamps at every joint. I use both Hillman and Split Jaw clamps. Clamp all swithes at least on one end so you can easily take one out for repairs. At all the rest of the joints use rail joiners and leave space for the track to expand. With aluminum track you will have to go back occaisionally and adjust the track by cutting off a small part or putting in a plug due to the constant expansion and contraction, particularly if you live where it gets hot like I do. Fasten the track to your roadbed about every foot in the curved sections and two feet on the straight sections. Once all this is down and functioning correctly then you can ballast it. If you want weathered looking rail, just paint the whole thing with Rustoleum camoflouge brown then wipe off the rail head while the paint is still wet. Do this before you ballast. Don't worry about painting the ties as the ballast will change their color slightly anyway. Good luck.

You don't say what you used for the base, but I use the split jaw pvc road bed. It's expensive, but it works great. We get torrential rains here so if I just laid the track down on the ballast it would all just wash away and I would be constantly adjusting the track grade. This way the ballast may wash out but the track stays firmly in place.


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## armorsmith (Jun 1, 2008)

@Dirk- Only the first loop will be track powered (I have the trak), all expansions after that will be aluminum. I will keep the track powered section for visitors to run on, and allow me to make the transition to battery over a longer period of time. 

@John - In the beginning, there was sectional track...... Gotta use what I got, too much money invested - although at the current pricing I stand to make a good few bucks if I sell it off. As for road bed, I stated above it will be a ladder system of PVC pipe risers with 1/2 x 1 1/2 PT stringers and blocking. One day the road bed will be buried and not see so much of the heat. Game plan, such as it is, will be to bring the fill dirt up to the bottom of the stringers and finalize the track contour with appropriate ballast material. 

Bob C.


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## Dick Friedman (Aug 19, 2008)

I use Llagas Creek code 250 aluminum rail on my layout in Sacramento. I laid my original track in early May, and ran the rails tight together, clamped with Hillman Clamps. The rail does expand and contract some, but since the track is in both sun AND shade, and the track is not held tight to the subroadbed, there does not seem to be a problem. 

Each six foot section is clamped to the next. I put a six inch square of Trex under the joints and screw the ties (which actually are not screwed to the rails) to the Trex about two inches on either side of the clamps. The joint is very rigid, but the rail between the joins floats in ballast. 

When I laid out my tunnel, no matter what I did, the joints wound up in the tunnel. So I just had a friend weld two six foot sections into one 12 foot section. No problem! 

I did this about ten years ago, and have had only one location where the rails came loose from the clamp. By coincidence, I fixed that today. 

I use track power, so have put power to the rails in two spots, about 65 feet apart.


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## Dick Friedman (Aug 19, 2008)

One more thing. Large Scale flex track is very flexible, and won't hold a curve very well. Beg, borrow or join a club to get a rail bender. Once the rail is bent with a bender, it will keep that curve. Else the track will try to straighten itself out. 

Don't ask me how I know this.


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