Wiring Walthers Double Crossover

Wiring the Walthers DCC friendly double crossover is a bit of a mystery to a lot of folks including apparently the techies at Walthers! I received the following email pointing out just how bad the problem is.

I have an HO scale Shinohara DCC friendly double crossover #6 switch, code 83. I read your article on wiring this switch up. The big mystery is how and where exactly do you solder the single wire (Tam Valley) to the insulation frog without melting the plastic surrounding the frog points? I addressed this issue to the Walthers tech support and to Tam Valley – they had no idea!

So over the weekend I finally got out my crossover and dug into the solution. First let’s look at the colored version of the crossover. If you look close you will see a number of frogs and complicated track pieces. Those of the same color are interconnected with jumpers on the bottom of the crossover. By simply connecting them to a piece of powered track they too will be powered making this a pretty easy part of the installation.

But what about the frogs? There are actually six of them to deal with. The two frogs in the middle of the crossover are plastic castings and cannot be powered. However they are short so shouldn’t create much of a problem. That leaves the four frogs shown in green. These frogs are electrically dead and isolated but do not have any provisions for attaching wires to them should you decide to provide a power connection. Consequently I decided to do what I have always done, solder a feeder wire to the side of one of the rails that make up each frog.

This is a little more challenging than it sounds so let me explain. Unlike most turnouts with solid cast frogs these are made up of individual pieces of track so you have to be very careful when soldering a feeder to them. Too much heat can result in a piece of rail moving out of place creating clearance issues, or worse. You can also melt the small molded plastic inserts that isolate the frog resulting in a short.

Here is my procedure. First I used a small metal brush to clean the locations on each frog where I wanted to add a feeder. I then dabbed a bit of rosin flux on the cleaned spot. I turned up the soldering iron to a high setting (750 degrees) and quickly melted a thin layer of solder onto the rail. This is a tricky operation since you need enough heat to heat the rails enough for the solder to adhere to them, but too much heat can melt the plastic. You can try adding heat sinks to the rails outside the work area to help prevent melting the plastic.

With the frogs ready I cut 4 20 ga feeders about 9” long, stripped about 1/2” insulation off each, bent the ends at 90 degrees, and applied some flux and solder to each. Here’s where this gets trickier and you have to work fast. Using my left hand I held the prepared feeder tip against the spot on the rail where I had applied the solder. Using a fine tip I applied heat to the spot just long enough to melt the solder then pulled it away. Before moving to the next frog I gave the feeder a tug to make sure the joint was solid. Like I said, work quickly and get the soldering iron tip off quickly. If you have an old Atlas or other inexpensive turnout practice on that before attempting this on such an expensive crossover.

Once you install the crossover you can either use a Tortoise SPDT to control the polarity of each frog or wire in a quad Frog Juicer to do the work automatically. Depending on how you set up your turnout controls you actually may be able to wire pairs of frogs to the same polarity switch. In my case I use only one Tortoise to throw all four sets of points so I can get by with a dual Frog Juicer to control polarity of the pairs of frogs on each side of the crossover.

8 comments

  • keep in mind that a short from a derail on the frog can easily destroy a smaller gauge wire so 22 would be my lower limit.

    • While I generally agree with your comment as long as the booster or circuit breaker does its job the wire is unlikely to have a high enough amperage going through it long enough to melt it. As for resistance effects as long as a very short feeder is used it also should not be a big issue. I still stick with my 20-22 ga solid wire. I have never had any problems hiding these wires by soldering them to the side of the rail web on the side away from the aisle.

  • Hi Larry, You mentioned using a heat sink in your blog to help prevent the melting of the plastic ties. In my days of soldering, I used a pair of alligator clips to be clipped to the rail one placed on both sides of the area where you would be soldering. Sometimes I would even use a damp small sponge (one that is meant for a soldering iron station) and place it close to the area that is being soldered. This practice should dissipate some of that unwanted heat. Bob

    • Yes, I mentioned those techniques in my DCC Corner column in the August 2017 issue of MR. Heat sinks can also work against you in some cases since they can draw heat away from the work while you are trying to solder so you have to be putting on enough heat to compensate and they can’t prevent softening or melting plastic at the point of contact. It really is a balancing act to get enough heat to do the job while not overheating things.

  • I am glad I did not buy one of these.

    • Yes, they would be a lot more forgiving if they had solid cast frogs like Atlas or Micro Engineering. Better yet would be solder tabs or a wire connected to the frog like Peco. Fortunately I have been sodering feeders to the sides of rails lkke this for long enough to have it down to a science.

  • Larry, I’m wondering why you used 20 ga. wire for your frog feeders. Considering that the close by surrounding rails were wired separately, and that probably only one loco would be on the frog at any one time, I would think that you could have gotten by with a lessor wire size.
    I assuming that a smaller size wire would be easier and faster to solder, but you probably know the definition of “assume”.
    Don

    • Yes you can probably use smaller wire But I have been using 20-22 ga wire for feeders for ages so that is what I used.

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