Putting the uncoupler on your layout requires a transformer, wiring, pushbutton, and the other things discussed above. It also requires great attention to track height as it passes over the uncoupler. The top of the plates should be anywhere from exactly even with rail height to 1/30th of an inch higher than the rail. The higher the plates, the stronger the magnetic pull on the coupler trip pins. For roadbed, regular N-scale cork roadbed is a bit too thick and even 1/8-inch cork sheets from the local home improvement center are sometimes, but not always too thick, but Foamies, which are found at craft stores for around 59 cents each (and make perfect model highway and road material and come in concrete, asphalt, and brown colors), are absolutely perfect for uncoupler roadbed. I suggest 6" x 1.125" Foamies strips (they come in 9" by 12" sheets—one sheet does eight uncouplers) at each end of your uncoupler in place of roadbed. I use the brown ones. Once roadbed, track, uncoupler and wiring are in place, put cars on the track and test it again. Note: If you must use cork sheet or cork roadbed, just shim the lower track mounting plate (see italicized part of next paragraph).
If the plates are over 1/30th of an inch higher than the rails, put paper shims under the roadbed. If they are even slightly lower than the rails, either get thinner roadbed or add paper shims under the four lower track mounting plate tabs. The latter will have no effect if your roadbed edge is on top of the ends of the lower track mounting plate (between the tabs). Make the roadbed end at the edge of the plate so that raising the plate via tab shims doesn't also raise the roadbed. Make sure no low-hanging trip pins are going to be hitting plate tops (test your lowest trip pin car now). Once everything is working perfectly, test locos and make sure none have wheels that cause short circuits and cause the loco to stop. If any do, you'll have to bend the field plates closer together. In my experience, 6.2mm is best, but O.D.s (of the top edges of the field plates) of as little as 5.75mm will work nicely too, and will surely fix the short circuit problems. I'm not even sure there are any wheels strange enough to cause this problem at 6.2mm, but if there are, you'll know what to do.
For finishing touches, you'll have to ballast all along the mounting plate sides and on the Foamies or cork to which you've nailed the track. And that's it—you're done!
In order to avoid a confusing jumble of wires under your layout, I recommend neatly organized wire busses that go everywhere so that adding another element requires no crawling around under the benchwork, but merely reaching out with pliers and 3M Scotchlok #905 connectors to the nearby wire bus. (Helpful hint: these will take run wires of #14 to #18 according to the box but #10 to #12 according to the 3M catalog. You can go anywhere in that range if you're careful and do it right. Stay with #12 for busses and use #18 to #24 for the "tap" wire from the bus. (If you need to tap a series of wires from your tap wire, use all #18 stranded wire for tap from run and tap from tap and Scotchlok 905s.) If your tap wire is pretty loose in the Scotchlok's tap hole and tries to fall out when you crimp, give yourself a break and switch to #18 stranded for your taps. If you insist on thinner wire, you may be able to double it over like I do before inserting into the hole. But it's vital that the extra folded-over wire faces the metal tapping blade of the Scotchlok. If you do this wrong, the crimping of the connector will either cut your tap wire or nearly cut it and your connection will be poor or nil. If used right, these devices will save your lungs from a lot of soldering fumes—I highly recommend them (I bought a whole case).
I have special pairs of single-conductor #12 stranded wire busses that go everywhere my benchwork goes. Two of these are 24-volt AC (2 amps) and are exclusively for uncoupler power (don't forget pushbuttons or other momentary switches in all uncoupler circuits). Two more are for lighting power and are 12-volt AC. And two more are for 73 tortoise switch machines, four Circuitron AR-2s and four DT-4s for auto-running, auto-reversing, signal activation, etc.—these are 13.8-volt DC (Radio Shack has a dandy 13.8-volt DC power pack). An extra bus wire is connected to the 6-volt winding on my 12-volt AC transformer and it's my panel light power bus. It's used with either 12-volt wire to get the 6-volt power. Panel lights are usually too hot and bright at 12 volts, so that's why this extra bus wire is needed. There are NO busses that relate to track power or throttles, and there's good reason for that—I hope to get into that in a future article. Anyway, with 23 uncouplers on my layout, it seemed wise to avoid messes and find a way to keep wiring simple and straightforward. I recommend this method.
Not Being Tripped Up
Monica had a bad trip named Tripp and now you have trip pins to trip you up, right? In other words, if you have 50 pieces of rolling stock to deal with, that makes 100 pins to bend. You say you'd rather have a root canal? Here's a word of assurance: First, once you get the hang of it it's easy and only takes a minute per coupler—or even per set of two. Second, if you're like the great majority of model railroaders, you don't do uncoupling on all cars. For my ten consists, I average two uncoupling points per train. It takes only four trip pin bends to ready such a train for action with modified #708 uncouplers. But even if you need to take an hour or so to do all your couplers because of your operations style, isn't it worth the time to kiss all the accidental uncouplings goodbye and avoid having nonprototypical-looking magnets all over your layout, as well as settling for letting magnet characteristics dictate switching locations so that many prototypical maneuvers are avoided? Besides, if you're like me, you just like to push buttons!
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