…you, too, can have the power
One of the breathtaking things about T-Trak layouts is the way they flout an essential rule of model railroading practice: don't depend on rail joiners to carry the current. Rail joiners are electrically undependable—everybody knows that. Yet we assemble a layout of perhaps dozens of modules, held together only by their joiners. When we connect a pair of wires at one end of the layout to a throttle, the trains somehow run. Usually, anyway. When I set up a layout, I like to have track power fed in from several points, if at all possible, which means equipping more modules with feeders.
Kato makes several items for connecting power to track, the most versatile being the 24-818 Terminal Joiners, which can be substituted for a regular pair of joiners, and located virtually anywhere on the railroad. The other end of the cable terminates in Kato's proprietary nylon plug, so unless you're willing to chop that off, you'll also need a 24-843 Adapter Cord to connect it to. Street price for both items together is about eight bucks or so, multiplied by two tracks on the module, multiplied by the number of modules you wish to equip with feeders. Can you afford to equip many modules like this? Me neither.
Fortunately, you don't have to. Once you know the trick, making your own terminal joiners is easy. All it takes is some wire and a modicum of skill with a soldering iron.
Start by disassembling a Unijoiner. The metal portion has tangs on both ends that hold it in the plastic portion. Squeeze these slightly with a fine-tipped tweezers inserted from underneath, and the metal part should pop right out. (A fine jeweler's screwdriver should work, too.) Do this somewhere where the joiner will be easy to locate if it flies away from you (the first one I did hid itself in the carpet for months before I found it again…lucky thing I don't vacuum too often). Secure it carefully in the jaws of a third-hand tool. (Don't have one of these yet? Harbor Freight sells a "helping hands" tool, complete with magnifier, for just a few bucks!)
Now prepare your wire. Here I'm using 22AWG solid wire (available in small spools at Radio Shack) for permanent installation on a module. If you're making terminal joiners for temporary use (say, a pair that can be installed between modules if a dead spot abruptly appears in a show layout), use fine (20-24AWG) stranded wire. Strip about 3/16" of insulation from the end, bend a nice sharp elbow about 1/16" in, apply flux, and tin the wire with solder. Apply flux and solder to the underside of the joiner, too.
Before soldering the wire to the joiner, thread it through the plastic part first (depending on what's already been done with the far end of the wire, threading it after soldering ranges from "slightly trickier" to "impossible"). Note that interior of the plastic has two little cross-ties molded in; the attached wire cannot interfere with these, or the joiner won't reassemble properly. Position the wire at the center of the joiner's underside, and touch it with the iron. Thanks to the pre-tinning you've done, a secure soldered joint should form almost immediately.
If the joint is properly aligned, neat, and sound, it's time to reassemble. Just slide the plastic up the wire, and click the metal into place (if it doesn't stay secured in the plastic, try bending the tangs outward just a little). Your terminal joiner is now ready for installation.
On my T-Trak modules, I've adopted the practice of terminating the track feeder wires at a terminal strip on the module's underside. Until the T-Trak community reaches a consensus on what plug (Cinch-Jones? RCA? Molex? PowerPole?) to use for complex layout connections, the terminal strip is adaptable to any situation. For my own layout, I use two-pin Molex sockets on short pigtails, which can easily be removed from the terminal strips and substituted with Kato plugs (cut from terminal joiners used elsewhere, and saved) if need be. In a pinch, even a scrap chunk of speaker wire can connect the module to the power source.
The power now goes to where you need it. Run some trains!
Additionally, when making a bunch of feeders, slide the metal joiners onto a piece of discarded rail. Once secured in the third hand tool or even a vise, you can make many joiners in assembly-line fashion.