Fred,
Thanks for the very informative advice. I like the idea of replacing straight sectional track with flextrack. It certainly makes a lot of sense.
I will take your advice about the terminal joiners. I will be starting to lay track this week. It really is great being able to draw on the experience of all you guys. What a great hobby this is!
Tom
tomfer wrote:Do you mean I should solder each railjoiner? If I do that, doesn,t it create a solid joint that cannot expand? I want to do this right.
To run your layout (4x8) with DCC (and I'm assuming insulated frog turnouts such as Atlas), only 2 connections are required, one to each rail. However, as Chuck pointed out, most folks eventually have at least one rail joiner fail to conduct properly - and often on an intermittent basis - which means mysterious "dead" sections of track.
There are 3 ways to ensure long term conductivity between sections of track apart from rail joiners:
1) as Chuck suggested, solder jumpers around each rail joiner
2) solder the rail joints together
3) provide separate feeders to each section of track
All are a fair amount of work to prevent a problem which may never happen. Personally, I use method 3, but I don't use rail joiners for the most part, and usually use handlaid track. Soldering the rail joints is almost mandatory when joining "springy" flex track (such as Atlas) on curves to prevent kinks, as well as provide electrical conductivity.
My suggestions in your particular case would be to:
1) replace multiple consecutive straight sections of track with flex track to reduce number of track joints. This is especially effective when numerous small "fitter" pieces of sectional track are used. Get a pair of rail nippers to cut the flex track. Leave the curves as sectional track.
2) My recommended minimum wiring for problem prevention: put a terminal rail joiner on both rails in the middle of each major curve. Tie these to your DCC busses. Do the same for each track that goes down the sides of the layout - one terminal rail joiner in each rail. That means that each loop will have 4 sets of feeders, and each siding or spur will have a set of feeders as well. You can do more, but I believe this is a reasonable balance between overkill and potential problems. Ideally, I would solder the rail joints and terminal rail joiner as one solid unit. If you are adding more feeders, I would first put extra feeders on the major curves as these have 6 sections of track each.
my thoughts, your choices
Fred Wright
My track will be on a foam bed (woodland scenics-grand valley layout) This would solve the problem of wood expansion I imagine. I have another question-I will be using terminal rail joiners and attachingn them to bus wires that are attached to a digitrax zephyer. How many railjoiner terminals should I use. (4x8 layout)
Thanks for the info. I,m new at this. Do you mean I should solder each railjoiner? If I do that, doesn,t it create a solid joint that cannot expand? I want to do this right.
Chuck
I'm guessing, but I'm thinking your relative humidity is staying fairly constant, but absolute vapor content is not. Relative humidity is based on a percentage of the total water vapor that air at that particular temperature can hold. The maximum water vapor content of air varies widely with temperature. 90% relative humidity at 95 degrees is a whole lot wetter than 90% humidity at 35 degrees! That is why in Indiana, 50% humidity at 105 degrees (not uncommon summer condition) is really pretty wet compared to 80% relative humidity at 28 degrees (winter condition). Cool that 105 degree air with only 50% humidity to 75 degrees and see how much water you condense out of it. So your wood is going to absorb more water (and expand, especially across the grain) at higher temperatures than at cooler, despite constant relative humidity.
Rail does expand with heat but it takes a large temperature change (which you have) or long runs of continuous (soldered connections) rail for the expansion to be significant and cause problems. In most cases, the expansion/contraction of the wood benchwork due to water absorbtion/drying is much greater than the expansion/contraction of the rail.
Chief Engineer, Wiper, and Bottle Washer for the
Picture Gorge and Western Railway
in foggy coastal Oregon where it's always 100% humidity and it's still 1900
tomfer wrote:I am starting to lay atlas ho sectional track on a new table. The temperature in my garage where the layout will be ranges from 50-85 degrees. Right now it is at the 85 level. I read that track will expand and contract. Because the tempm is at its highest now, should I lay the track with no spaces at the joints ? I'm thinking when it gets cold it will contract. I am using rail joiners between the tracks.
My layout space has a potential temperature range of 100 degrees F (113 today, 125 easily possible in July, subfreezing possible in January). I laid 36 inch lengths of flex in the spring (55-65 degrees) with fair-size gaps, and now have much smaller gaps. Since humidity is about the same, the only conclusion that I can reach is that rail DOES expand with heat.
You are working with much shorter rail lengths (9-10 inches, rather than 36) and a smaller temperature range. Were I you, I would lay the sections with gaps about the size of a human hair (just in case the AC fails during a record heat wave) and be sure to either feed every single rail with a drop or solder jumpers around all uninsulated rail joints. Some modelers have reported years of trouble-free operation using only the metal rail joiners for conducting power, while others (including myself) have had mysterious "sometimes" open circuits that were eventually traced to rail joiners that had stopped feeding power to the rails beyond. Still other people solder every rail joiner, effectively eliminating any chance that the rail can relieve expansion stress. My answer to that is to reread my first paragraph.
A little trick that will help eliminate future derailments is to de-burr EVERY rail end, and file a tiny bevel in the top inside corner (where the wheel flange rubs the rail.) Doing that has made derailments an unknown phenomenon on my 26-year-old module (all hand laid) and on my recently dismantled half-a-garage layout.
Careful tracklaying now will lead to carefree operation later.
HiAll,
I am starting to lay atlas ho sectional track on a new table. The temperature in my garage where the layout will be ranges from 50-85 degrees. Right now it is at the 85 level. I read that track will expand and contract. Because the tempm is at its highest now, should I lay the track with no spaces at the joints ? I'm thinking when it gets cold it will contract. I am using rail joiners between the tracks.