There have been many threads that have related to track laying and the do's and don't of soldering the rail joints. I would like to hear from those who "have" soldered all their rail joints. I fail to see where expansion would be a problem where temperature is kept to a realtively close tolerance.
If the train room is say 68F, and does not vary more than say 2F to 4F, there is no way that the track metal can expand enough to cause a problem...sorry , the physics just don't support it.
The material that the tracks are set upon is another matter. Wood is notorious for absorbing moisture and expanding in humid conditions, and likewise will shrink when too dry. But if the tracks are buffered from this base material, or, the room is held in good RH tolerance ( 40-60% ), then this should not cause any problems either.
So lets hear from you guys who have soldered every joint and have no problems with track warpage due to soldering all joints.
I solder most joints, leaving gaps every six to ten feet and do notice a variation in gap width from hot humid summers to dry cold winters (train room is heated to 45F in winter unless I am in there, In summer it gets as hot as it likes (up to about 95F). Never a problem but the gaps do change in width from 1/32" to about 3/32" worst case. The wheel sound changes too of course.
I believe, but have not scientifically proven, that curves self adjust somewhat for expansion / contraction by moving on the WS roadbed even when ballasted.
Personally though, I would be wary of no gaps on long straightaways. The math will surprise you in lateral or vertical displacement for even a tiny bit of extra length. For example, consider the approximation of two five foot lengths of rigid pipe pinned at the ends and connected with a hinge at the enter. A 1/16" increase in length over the 10 feet will displace the center over half an inch according to pythagoras. We probably don't need to bother with the calculus that models the exact behavior of track to see the type of effect.
There have also been photos posted on this site of warped track. As they say "a picture is worth a thousand complicated equations". Always better to err on the side of caution.
Karl
The mind is like a parachute. It works better when it's open. www.stremy.net
I have a 13X24 layout that is fifteen years old. When the main line was laid that first year, ALL joints were soldered. The first year and a half, I had to cut and resolder about a dozen joints due to kinks in the track. I am certain the problem was due to the new benchwork drying out and settling in to its new environment. Since that time, I haven't had a single problem with any track kinks.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
IF you have a layout space conditioned like a NASA clean room, you could weld your rail ends together and run on honest-to-Murgatroyd Ribbonrail. with joints only where required by signal detection...
Reality check time. My layout resides in a space where the temperature can swing 50 degrees over a few hours, and close to 100 degrees over a year. Thanks to local building codes and a gas-fired hot water heater, I have to have large vents open to the outside, so serious climate control isn't going to happen. I have laid track with no end play at 116 degrees in August, and found the gaps to be over a millimeter on a sub-freezing pre-dawn in January. (No, it's not humidity. My benchwork is steel, and the track is laid on foam.)
I haven't had a problem since I don't solder my rail joints. I get bulletproof electricals by soldering jumpers around my joints, leaving them free to move. Given the above, I'm not about to tempt fate by changing my procedures.
Just my , based on my location. Others are sure to have different results.
Chuck (modeling Central Japan in September, 1964 - in a Mojave Desert garage)
Jeff But it's a dry heat!
I have a room-size layout in my basement with about 180' of mainline. I soldered it all together when I built it 16-or-so years ago, then cut gaps to isolate passing sidings. The room is unheated, but well insulated, and I've had no problems with expansion or contraction.
Wayne
My layout is built with flex track, but the bench work is in 8 foot sections, bolted together, so that it can be dismantled with the sections connected with a piece of snap track. The snap track is not soldered or fastened down, everything else is.
No problems.
Something I would do different if starting over would be to use tongue & groove plywood on top of the bench work so that the joints between the segments would maintain perfect vertical alignment.
Dave
Lackawanna Route of the Phoebe Snow
Dr. Frankendiesel aka Scott Running BearSpace Mouse for president!15 year veteran fire fighterCollector of Apple //e'sRunning Bear EnterprisesHistory Channel Club life member.beatus homo qui invenit sapientiam
Andy Sperandeo MODEL RAILROADER Magazine
Jay
C-415 Build: https://imageshack.com/a/tShC/1
Other builds: https://imageshack.com/my/albums
I posted this quote from a "mrhedley" on ModelRailroadForums.com in a recent thread on this very question. Here, once again, is his post:
"The Mark's standard handbook for Mechanical Engineers lists the coefficient of Thermal Expansion for Nickel Silvers as 9.5 x 10 -6 inch/inch per degree F. For a thirty degree difference between the temperature at installation, that is approximately 1/4" in 100'."
Since virtually no one solders more than three sections of flex together, we can interpolate and decude that a 9' section of soldered rail would expand something like 0.025" attributable solely to a 30 deg temperature change. Even if you measured at each end the change in 100' of solid NS rail, that change at each end would amount to a whopping 1/8". Hardly enough to get one's knickers in a knot, unless no movement was permitted by the roadbed.
My point is that a slipping or gapped joint every 6-30' is going to solve any temperature problems 99.9% of the time. The problem is moisture...period. As your benchwork shrinks linearly along the grain due to drying spells, it will want to compress the rails to which it is adhered along the same vector. So, rails aligned in parallel to the major axis of shrinkage are going to deflect when they are bound by solder that doesn't permit slippage in metal joiners.
So, do have broken rail meets every so often, and you won't have to worry about either issue.
Hey Dick,
Yea, I had that issue last summer on some of the track segments and so I took a razor saw and made a few strategic cuts to gap the rails here and there to relieve the pressure of the track expansion. Since then I have not had any issues, but summer is still a few months away and hope to not see a repeat of the same. Since then I have added more non-soldered joints between 3' flex track segments, and make a better attempt at putting a small gap between for the expansion areas.
Ryan BoudreauxThe Piedmont Division Modeling The Southern Railway, Norfolk & Western & Norfolk Southern in HO during the merger eraCajun Chef Ryan
selector wrote: Even if you measured at each end the change in 100' of solid NS rail, that change at each end would amount to a whopping 1/8". Hardly enough to get one's knickers in a knot, unless no movement was permitted by the roadbed.
Even if you measured at each end the change in 100' of solid NS rail, that change at each end would amount to a whopping 1/8". Hardly enough to get one's knickers in a knot, unless no movement was permitted by the roadbed.
If the ends are well and truly fixed (which is probably not really that likely) an eigth of an inch is a lot to get rid of! If I did the math right (an there could be a half in somewhere, depending on how we want to define things) there are about 17 inches worth of displacement to get rid of. Now, it is probably never going to be tht bad, because everyting is allowed some movement, but it strikes me that a little gap in th rails every ten feet or so is a small price to pay for not even having to worry about it.
Jeff, that's 1/4 inch length difference over one-hundred feet of contiguous (solid, continuous, or soldered) NS rail. That means, if you stand at the very centre of a length of NS rail that long, watch the temperature rise 30 deg, and then walk to each end to measure, you will find that the ends have moved a mere 1/8" away from the place you left a minute ago...the centre. So, the expansion of NS track is not going to be a problem in thermal dimensional changes. Instead, it is only when it is compressed as the surface on which it is fixed shrinks due to temperature changes (unlikely), or changes in humidity (more likely). The metal doesn't want to change shape, and certainly not length as its supporting bench begins to shrink as dryness sets in. It has no choice, if fastened securely, but to buckle sideways in an effort to relieve the compression that the bench is forcing upon it.
Think of it like this: Bench this long: ________________________________-
Rails are this long: ________________________________
Bench wants to reduce its length due to interstitial moisture loss, so it reduces its lenth to:
______________________________
Rail is still this long: ________________________________
But the bench won't let it go, so the rail develops a bow in order to accomodate the bench, and to maintain its linear dimensions. I am not saying not to cut the gaps...quite the opposite. I am just wanting us to get off the notion that our problems are anywhere nearly shared equally by thermal expansion. It's not. It is more like 10% due to thermal expansion if we don't cut gaps every so often, and 90% due to changes in moisture content in the materails we use...except for Chuck.
So, let's say we both solder three full lengths of flex. We each fasten it quite securely, but it can still buck if it really wants to. I keep my humidity constant, but I raise my temperature by 30 deg. I can expect my rails to want to lengthen, if they are NS, by 1/10th of the 100 feet figure I quoted above. I would have to look for 1/10th of 1/8" of an inch growth on each end of that nearly 10' soldered length. You, on the other hand, keep your temperature the same, but you drop the moisture content in your bench from 65% down to 38%. I don't know what changes in length that would mean, but I bet it will mean a lot more than the change caused by my temperature growth, probably four or five times as much....at least. If the ends are fastened securely, then we are talking a deflection accomodation for about 1/16", which must trig out to about 3/4 or more of a bow. But if we gap every 6-10', even the shrinking you experience won't be a problem, because you will have the room to collapse into at those joints.
-Crandell
Thank you everyone for great replies. I live in central Massachusetts, and the outside humidity ranges from a low of 15% in Winter to 100% in Summer. The temperatures range from -10F to 105F in extremes, typically 10F to 90F. INSIDE, having a well insulated house, the train room stays at 68F +/- 5F year round, and the RH ranges from 35% to 55% which I can control with a dehumidifier to 40F +/- 3F as required.
I used 3/4" plywood, painted the surfaces, and glued 2" foam to the top. I waited a year to install tracks to allow for any moisture to be driven out of the wood, call it "stabilization" time. ( I needed the time to do the wife's Honey Do jar projects anyways ) Plywood, up until recently, was flying off the shelves at lumber yards as fast as it arrived from the mills. So you just know that the wood had considerable moisture content.
As I suspected, and you guys have verified, the real problem is with the material that the tracks are attached to. Block control will dictate that separations in the tracks will need to be made anyways, so that will end that issue. But for layouts without block control, and therefore possibly no unsoldered joints, the underlying material must really be matched for coefficients of expansion differential, or otherwise buffered.
This raises the question, if the foam were NOT glued or attached solidly to the table ( plywood ), the wood would be able to expand without the tracks being effected. I wonder if latex caulk, known for it's properties to expand and contract without cracking would be a good contact between the plywood and the foam?
selector wrote: Jeff, that's 1/4 inch length difference over one-hundred feet of contiguous (solid, continuous, or soldered) NS rail.
Jeff, that's 1/4 inch length difference over one-hundred feet of contiguous (solid, continuous, or soldered) NS rail.
I agree with this, I don't agree that it is insignificant.
Over 10 feet, you have .025 inch of expansion (assuming it was laid at the coldest, which we know won't be the case). So, if the benchwork is absolutely fixed, and the ends are absolutely fixed (more stuff we know can't really happen), the middle of the section will have to displace over 0.3 inches, which is quite a kink. I have always held that the benchwork is the more unstable element, but when I did these calculations I was surprised! (And I still the that the benchwork is the larger contributor in most cases). I the track is all soldered together, and floating, it doesn't really matter. If it is all soldered together, and points are really secured, something has got to give.
In almost any case, I think that not having gaps at reasonable intervals (10 feetish?) is going to cause trouble, eventually. On another forum a guy had a layout for sometime with no trouble. Then the AC went out. Mulitiple failures overnight. If we don't plan for movement in our layouts, movement is going to get us, almost guaranteed, someday.