DCC wiring for closed frog switches

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The club I belong to runs both scale and hi-rail S gauge equipment. Consequently, we must use closed frog switches - the points and frog are all one unit. What is the best way to wire the switch for reliable DCC operation? Thanks for the help.

John Gibson Rocklin, CA

-- John Gibson (gibson@pdqnet.com), January 07, 2003


Since I've seen two types of switches that might be described as closed, I'm not exactly sure I know what you have. Maybe there are other varieties as well. In the cases I am thinking of, there isn't anything you can do for them.

In one of the two cases I am thinking of, the frog is such that shorting due to a derailment isn't likely. So that part of a turnout problem isn't an issue. In this case, your only problem is at the points.

I don't hear from the O and S people much. If you do anything, there is the usual suggestion of a bulb or a electronic circuit breaker in series with the feed to the frog (and your case, the points).

Always remember, you don't have to do anything. The main reason for doing anything, is to keep from shutting down an operating session. If you have a small layout - relatively few turnouts, few trains, and few operators (typical of the larger scales) - the consequences of ruining an operating session diminish. Bulbs and things also help localize a problem. If you are a sole operator running one train and it stops, then the problem is pretty obvious! My HO has a bulb per turnout. My G has nothing.

If you want to put in bulbs, look at my web page for the Kato Unitrack description. http://www.WiringForDCC.com. It's an example of a turnout that you can't change. (I understand some models are different. For your purposes, I believe its diagram will do.)

Note: I haven't tried the bulbs on S. If your locomotives don't draw substantially more than HO locomotives, they should work fine. Bulbs will always work, but you may need a different bulb than the popular 1156. The only way to know which bulb you should use is to try different ones. (Ideally, if you had the data sheets for the bulbs, you could come up with some good guesses. But automotive bulbs frequently don't say how much current they draw on the package.)

-- Allan Gartner (bigboy@WiringForDCC.com), January 07, 2003.


Thank you for the prompt reply. The switch is made by BK and is pre- assembled -- all I have to do is spike it down. If you are not familiar with these switches, I can post a picture if you tell me how to do it.

Yes, I agree. After re-reading the turnout section and studying the Kato Unitrack description I think that example is very close to my situation, I certainly don't have the run of the mill DCC friendly turnout. :-) Thanks for your help.

-- John Gibson (gibson@pdqnet.com), January 08, 2003.

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