I had no idea that code 55 joiners could be used with Unitrack. I'll have to remember this! I used Unitrack on my current layout and I do have the differences in height on some of the rail joints. It's my biggest complaint (aside from appearance). The code 55 joiners - are these the Atlas ones?
Yikes, looks like they were squeezed out with a caulk gun by someone who'd had too much coffee and tried to counteract it by drinking an equal amount of whiskey. All during an earthquake.
Just an aside here but Peco uses the same rail joiners for both its C55 and C 80 track. I am not sure about Atlas though.
Affirm, I used atlas code 55 rail joiners. I removed the metal piece from the uni joiner and filed out the top of the plastic bit so it could still be used to hold the roadbed together. The code 55’s slip right under the rail and over the plastic part.
I have soldered joints on layouts in the past but I didn't on this last one and it's about 10 years old and trains run fine. I just made sure the joiners were nice and snug. Doug
A few thoughts... Curved rails move in the same direction (outward during expansion, inward during contraction), thus having less impact on track gauge and keeping the trains upright. While one episode of temperature change will still cause the same expansion/contraction, it is repeated episodes that weaken the structure that returns the rails to their proper spacing afterwards. Humidity also affects the wood structure underneath the track (ties, layout support, etc.) but again, repeated expansion/contraction cycles weaken the structures that would return the track to normal. Ever wonder what those U-bends in pipelines are for? To allow for pipe length expansion and contraction. Just like proper woodworking techniques in furniture design (like floating panels in doors, or properly fastening solid wood table tops to the base to allow for the top to expand and contract across the grain, without bowing or cracking, or tearing the frame apart. Wood expands very little in length with change in temperature and humidity, but lots in width.
But if all the joints are soldered how can the rail expand or contract. It has nowhere to go, nowhere good that is. But it will go somewhere so on contraction the rail will pull to the inside of the curve and on expansion it will push to the outside of the curve and those little plastic nubs that are supposed to represent track spikes won't be able to contain the rail. Just because a rail expands in one direction does not mean it will contract in the direction opposite of the expansion. It may or it may not. Wood expansion and contraction due to humidity changes are easily resolved with an application of a good wood sealer/primer topped with a coat of latex paint. Easy, peasy.
Methinks Big Jake is advocating against soldering everything so the rail can't move. When MR constructed the NY&Q N scale layout in the 1968-69 season, they had trouble with kinked rails when they didn't allow gaps in some places to allow for expansion/contraction. And, if I remember correctly, they didn't even solder the joints. They just didn't leave any gaps, at all. Doug
I am an advocate of not soldering track joints and leaving a gap of .015 inches between pieces of track no matter what size (up to 36 inches long). That gap is sufficient to provide protection for expansion for a 100 degree increase in temperature. So, if you lay your track at nominal room temperature of 70 degrees you are good up to 170 degrees. If the temperature ever gets that high, you won't worry about track expansion because you will be dead already. So how big is ,015 inches? Get a piece of K&S brass angle. The thickness of each leg of the angle is .015 inches. Not enough to cause a derailment as it is smaller than the .022 flanges that are now standard on rolling stock. And don't rely on having a controlled environment. Storms, like other things, happen, power outages occur and controlled environments can disappear.
Instead of using your credit card to buy K&S brass angle...just use the credit card to make the gap. Most credit cards are pretty thin.
Ever heat a bearing/sleave/etc. up, to slide it into position on a shaft, and watch what happens when it cools? Ever sweat a copper pipe joint? Why does the solder seep into the joint between pipe and fitting? Because the outer fitting, closer to the torch, gets hotter, while the copper tubing underneath it is shielded and does not get as hot. This creates an expanding gap between tubing and fitting, which sucks the solder into the joint. But the solder solidifies in place before the copper stops contracting, as the joint approaches room temperature again. Finishing/painting wood will NOT keep it from expanding and contracting due to humidity changes. And paint/finish will do nothing for thermal expansion due to changes in temperature. I don't know too many people that keep their indoor air at the same temperature or humidity year-round. Painting & similar finishes will slow down how fast the wood adjusts to the surrounding humidity, but it will not stop it. The seasonal changes from heating to cooling are plenty long enough to outlast the delaying effects of any paint or wood finish.
"Oh, bother;" Pooh said. Just use Unitrack, and solder feeder wires to some* of the Unijoiners (or purchase pre-wired Unijoiners). Problem solved! *how many/often is a whole 'nother argument, but somewhere between only and every one.
All very interesting, but no one has talked about the importance of the thermal expansion coefficient of their substrate. Let’s look simply at wood one source simply says “wood, with the grain 3x10e6 in/deg C” and “wood, across the grain 30x10e-6 in/in/deg C” (inches per inch, meters per meter, light year per light year, doesn’t matter) How does that stack up against the thermal expansion coefficient of your rails? Assuming “nickel silver” rails (essentially brass with some amount of nickel). Without knowing it’s exact composition, but knowing it’s akin to a Nickel-Aluminum Bronze, or a Copper-Nickel, the same source says both of those have coefficients of 16.2x10e-6. So, what do we do now with the wood? Well, table surfaces for model railroading are frequently made from plywood, with plys oriented at 90 degrees. So, do we average 3 and 30 for 16.5? But plywood is made with an odd number of plys. If it’s say, 5-ply, then along the length of the board it’s 19.2, and across the board, it’s 13.8. Of course you could go to the effort of cutting up your boards so you could install them in triangular pieces oriented with the grain at 45 degrees to the table axes to get a 16.5 degree average, but that’s a lot if work. And even if you think the work is worth it, it’s time to stop and think now: Your plywood substrate has an averaged (but directional) coefficient of thermal expansion of 16.5x10e-6 in/in/deg C. But wait, your rail has a coefficient of 16.2 in/in/deg C. The difference between expansion coefficients is going to determine the extent of an expansion problem a layout has, an d that difference, in the case of nickel silver rails, is -3.0e-07 in/in/deg C. Which is means, if you build directly to plywood, the net expansion of the rail with respect to the tabletop (substrate) it is mounted on is about two percent of that of the rail considered in isolation is. Which means if I consider, say, a sixty-degree Fahrenheit (yeah, we’ll adjust for that) temperature swing on my 21-foot inner loop, the expansion is: 60 x 1.8 x 21ft x12in/ft x -3.0x10e-07 = 0.00” Two point five thou. Which means the poster above with the 200-ft loop is looking at 0.025 net expansion of the tabletop w.r.t. to the rails, for a temperature span from 40F to 100F, of 0.025” But what about the negative sign on the net expansion coefficient? Well, it means the substrate expands more than the rail does as things get hotter, and what are the implications of that? Well, that means in such cases, you should be installing with the rail joints fit up solid on cold days, or installing with gaps when it’s hottest, because those gaps shrink when the railroad room gets colder. And what about the general practice of screwing down the plywood directly onto longitudinally oriented 2x4 lumber, that has a longitudinal expansion coefficient much smaller than that of either directional orientation of the plywood? Well ovalized plywood securing screw holes and gaps between plywood pieces may become the required norm. Then there is laying track on foam insulation board. I don’t have the information on it , but a look at thermal expansion coefficients for polyurethanes., thermo plastics, resins, etc., ought to make the model railroader realize that the opportunity for reality to be in direct opposition to the conventional thinking is quite large. There is more I could say, but I have to turn in.
