Atlas HO Flex Track problems

jerry lewis

New Member
Having trouble with my flex track kinking in the winter months. I live in Vermont and each winter the flex track on my layout kinks. The layout is located in my finished, heated basement which is also a living area. My benchwork is six years old and consists of plywood, homosote, and cork roadbed with Atlas flex track. I was told to seal the homosote and my problems would go away so, I tore up the layout, sealed the homosote on all sides and relaid the track -- it still kinks. I left spaces between the sections and I am having struggles accepting that my benchwork is moving. Quality plywood was used and it has aged over the pat six years. One of my modeler firends says that Atlas flex track kinks by itself because of the plastic? I'm not sure about that theory. I was also told to glue the track down instead of using track nails in the pre-drilled holes that exist in the track--that should solve my problem. At the moment I'am confused and serching for advice from experienced modelers who may have run up against similar situations. Can anyone help me? Thank you.
A model railraod lover (RUTLAND)
I have a similar problem on my layout. I have trouble when the temp is at the hottest and coldest because of track expansion. I nail the track at critical places where I dont want movement. I have a couple tunnels and I only nail about every 3rd hole and then only loosely so that the track can flex in the tunnel as needed. Make sure you have as much space between the sections as possible when room is at its coldest to allow for expansion at the warmest.

I have also found with flex track if you solder at the joints it is best to use a jumper instead of soldering the rail joiner so you dont loose that expansion joint.

In my opion gluing wont help and since I worked my kinks out I have started reballasting and havent had a problem yet.

Good Luck and hope that helps.
One short answer "De Humidifier"
I don't seem to have the track buckling, but when the unit (humidifier) wasn't running the gate jammed closed and when I did get it open I couldn't close it again. When the humid air does it's thing on the wood it swells so expansion is what causes the buckles. I also note it's only when humidity is high.
Anyway that's what fixed things for me.
I wont disagree that that can be part of the problem.

However , I have had 18' of flex track expand and contract almost an inch over a season. Plywood doesnt expand that much.

If the problem is in a basement in the winter when the heat is on in a living area then it would be dryer than the rest of the year unless a humidifier is on.
I wont disagree that that can be part of the problem.

However , I have had 18' of flex track expand and contract almost an inch over a season. Plywood doesnt expand that much.

If the problem is in a basement in the winter when the heat is on in a living area then it would be dryer than the rest of the year unless a humidifier is on.

Higher temp = a small amount of expansion in the metal in the track itself. Low humidity = shrinkage of wood (which can be quite a bit). The two may cause a larger problem than each alone. The best way to "solve" the problem is to keep both the heat and humidity constant. This is also why it is advised to not solder all the joints, but no more than 2 sections together and use feeders to each 6' section. Try to leave a 16th. inch gap at rail joints when you lay them under dry conditions. I have only had one kink (a minor one at that) this winter and layed about 100' of track last year. A dremel cut solved that.
Fellows, I am not saying that you haven't had problems with the track 'moving' on you, but to say a short (or long) section of rail expands and contracts 1" is a bit much for any type of metal. It doesn't take but about 1/32" too long for one side of a joint to considerably bow the the other side.

The last several years I have read of many problems with laid track walking or becoming misaligned and discussions of what environmental conditions are causing this. No one seems to agree and no one geographical area seems to have more than the other.

As a reply to what all you have said, my layout is in a garage that is separate from the house. It is only heated or cooled when I plan on working or operating in it. I have over 1,000 feet of Atlas Flex, soldered at each joint, ballasted only in viewed areas, and nailed about every other hole. I live in an area of very high humidity in the state of Alabama. My present layout is 3.5 years old and built with prime lumber and BC plywood. Maybe it is luck, but I do not and have not experienced any problems associated with the environment.

My personal opinion, is that the "track alignment" is not so much of the tracks expansion/contraction, but the benchwork itself. Remember that the frame and top are all mechanically fitted together in a way that each member supports or assist the other. So, if one area is stressed by the environment or other influences, then the whole section or area will try to adjust for the change.
I also believe that a lack of humidity is more responsible for the track alignment problems experienced by so many, than too much or from temperature variations. If your layout is in a dry area, then you should always season your lumber until it's moisture content will equal out with the average humidity in the layout room. If this is not done, then the drying effects will certainly cause warping regardless of the grade of lumber. Also and after the layout is built, you should try to maintain a steady humidity and temperature level.
If your area (such as mine) has higher humidity, then the chances of the lumber warping are less severe unless you make drastic and fluctuating changes to the ambient air. Still, care must be made to ensure that you have secured the parts of your benchwork properly with the use of many screws and supports, as the lumber will still dry a little more than when you bought it. The use of many screws where a few would do the job, will help keep the bench parts in place to the measurements that you built.

Please keep in mind that the above is my opinion and is not meant to be argumentative, but is posted to give another view in a positive way.
I agree fully with Ray. I have had two kinks in my short time in MRR, one was related to humidity, the other to heat. Allow me to explain.

The first was within two or three days after I had stopped heating my basement one spring. I found the stretch of flextrack running across my bridge deflected hard to one side of the deck. I purchased a dehumidifier, and within 24 hours it was back in line. Humidity does nasty things to your bench geometry for exactly the reason that Ray described. It pulls screws, staples, and nails out by their heads! Yep, it does. Think of what a tree root does to concrete and asphalt. It is hydraulic pressure.

The second incident happened earlier this winter when I had a good fire going on a cold day. I warmed the basement well to allow the slow-speed fan on the furnace to circulate warmer air throughout the house. The wood stove sits exactly 18" from one corner of the layout. Three feet away from the stove, on a very gently curve of maybe 120" radius, a section of flex that had been caulked to the splin roadbed had wowed outward by about 5/8"
...not a lot, but I heard it inside the tunnel where it happened when a train ran across it (ah, yes, always where it is least accessible).

On another forum, someone knowledgeable in materials science said that the nickel-silver rails will expand about 1/16" over 10 feet or so with a change in temp of about 20 deg. I don't honestly remember the exact figures, so don't put any stock in them, except that at the time, it was clear to me that rail expansion is not going to be a significant problem for most of us...only for those whose layouts are in places where there is a wide range between winter and summer temps. He pointed out that humidity is what causes the wider changes in position by causing elongation and then contraction of the wood along its grain. Since most dimensional lumber is cut so that the grain runs close to the linear axis of the lengths, you can see that humidity will result in significant length changes due to the individual cells expanding length-wise.

So, all this to say that if you don't want to operate a dehumidifier or an airconditioner (which dehumidifies at the same time, by the way), loosen your major fasteners in damper times by a half turn, and tighten them when you know the humidity will stay lower. This may not accomplish a great deal, but it will keep the humidity from tearing fasteners out by their roots and eventually resulting in a poorly fitting layout anyway. It may even save your alignments across seams.
My layout has been in my metal building for about 8 years. I have never had any warping at all. In the winter my inside temp. is cold & in the summer my inside temp is usually 10 to 15 degree's higher than the outside temp.
My tables are made out of steel & the plywood is 4 ply CDX. I used Homosote once about 15 years ago & had a mountain of problems. Now, I use plywood only w/cork roadbed. I have always used Atlas flex w/great results. I only glue my track in area's that I can't get to real easy & that is not very much.
All of my plywood is screwed down about every 12 inches. I use machine screws w/washers underneath. All my steel tables are welded together.
Like I said I've never had any warpage of a rail because of cold or extreme heat. Most of the time in the summer it gets 100 to 108 inside my metal building & in the winter it gets 24 to 35 degree's most times. All of my long bridges are made out of welded steel, so, I would never have any warpage there. I've been building layouts for about 45 years & have never used anything but 4 ply CDX, unpainted.

Hmmm! guess I forgot about that part, all my track is on 3/4 inch plywood, it hasn't kinked yet, however the 1x4 and 2x4 frame work did expand somewhat. I also have to admit it isn't painted yet. The basement is not normally heated with the exception of an electric baseboard heater in the train room which isn't on that often. I just use it to take the chill off in the wintertime.

Wish I could afford the constant environment but that isnt gonna happen. I keep telling my wife I am gonna take the wall down between the living room and the dining room. That idea never has floated.

I guess we all have environmental problems of some sort.

I wish I could control the 40 degree to 120 degree temps better but maybe next year. Am sure when I get it under control I will be pulling my hair out about that.
Probably the best way to go is take care of the condition that you have, i.e. normal is an average dry condition, but swells with increased humidity= a room dehumidifier, normal is an average humid condition, but contracts with decreased humidity= a room humidifier. Another thought is going to WS foam roadbed that has zero change regardless of humidity.

Ask yourself, does the rise or fall of temperature also result in a rise or fall in humidity. If so, adjust accordingly.;)
Good luck!:)
40 degree to 120 degree temps
Holy Cow! I only put on a little heat on in the train room during the winter, and the dehumidifier the rest of the time, If I had a spread of 25 or 30 deg's over the year that would be a first. Ah! just thought of it, the basement walls and ceiling are insulated, storm windows on the basement windows, so all that may have bonus effect on the temperatures.

Mine is a 24x32 room over the detattched shop and it is well insulated but the temp does sway and I picked up an AC this week so that should help this summer.
I had my first issue just a few weeks back on this current layout. I've never had an issue before, but there is always that first time.
I had a section between two turnouts (roughly 5' of track) and it expanded so much that it buckled a turnout (walthers brand).

So I did like the real railroad does, and made an expansion location, and cut a section of rail that looked right out. Then placed a smaller section in (one is a solid inch in length, the other is close to an inch and half long.)

The real railroads do this and they have locations that do this every year in the heat and the cold. This is why you might see a 10' section of rail just laying there by the tracks on the mainline.

Its an issue problem to solve. Get out the dremel with the cutoff wheel and remove about 1-2" of track, reconstruct the kink and fit a new piece in about a .010 gap in between the rails. When the kink goes out or the gap shrinks, install the old piece!
The real railroads do this and they have locations that do this every year in the heat and the cold. This is why you might see a 10' section of rail just laying there by the tracks on the mainline.

Another thing that helps the real railroads is that they aren't glued down!..They float in a bed of ballast..Kinda weird when you think about just lays there, floating in stones....Its as strange as how the lengthy rails loaded on cars wind thru turns as they are hauled to sites from the factory...but cut off a short piece and use it as an anvil to pound on and you can't imagine how its that flexible and how heavy it must be!....One of life's mysteries!!:eek:
One of the lines I use to work on, they laid a new industrial track. One day we were coming to spot a few cars on the local, when we noticed a nice 100 foot or so kink. The entire railroad has shifted over. This was fairly new track and I guess it didn't have any expansion to it. It was CWR, as it lead into a new grain elevator. The track forman had a section cut out and it pulled back into place.

The CWR trains are interesting. Luckily I had a few of them and got to see them snake from the cab. The best part is when they pull the rail out of them, just like a string. Very interesting to say the least.