I’m playing with arduino control of turnouts for a future layout, using a very basic u-channel servo mount. I have noticed that some of the servo mounts have an add on to adjust frog polarity. Is this necessary for DCC?
I’ve only run DC with Atlas turnouts on my old layout. My four-axle diesels traversed #4, code 100 turnouts without a problem. DCC is likely in my future. I’m thinking it should not be necessary to power the frogs but it is much easier to do initially than trying to retrofit later. Thoughts?
If you have a metal (conductive) frog, you can power it, but is must be in phase with the closure/wing rail and the point rails or you will get a short.
DCC Friendly Turnout explains it. Some switch machines do include contacts so you can power the frog and maintain the correct phasing in the process. For most modern locomotives with all wheel pickup, a dead frog isn’t an issue. If they work fine with your turnouts in DC, they will work fine with DCC (with a few caveats…)
Atlas #4 turnouts have plastic frogs and can’t be powered, as far as I know. You don’t need to power frogs just because you run DCC.
If you power a turnout frog you must change its polarity when the turnout is thrown or you will get a short whether the power is DC or DCC, makes no difference.
DCC more accurately has two phases rather than two polarities but for practical purposes you can consider that DC and DCC short out in the same way.
DCC power creates the difference between the rails by switching power on and off to each rail alternately many thousand times per second. The key is when one rail is on the other rail is off. If the rail that is on gets connected directly to the rail that is off, not through a decoder or a dc motor, then the powerpack overloads and shuts down. For DC the effect is the same just the technical cause is different.
All but two of my 26 turnouts are code 83 Atlas Custom Line and I’ve never had a problem with frog power.
All my mainline turnouts are #6 and all my yard turnouts are #4. I operate my layout dual mode, DC or DCC.
I custom built my own double crossover using Atlas code 83 #6 Custom Line turnouts and 19 ° crossover, 2” center to center. I went with wired frogs not knowing if they would be needed or not. Like you said easier to do before installation rather than after. Well it proved out that the frogs worked perfect without powering them.
My shortest locomotive is a Round House MDC 0-6-0 and I’ve never had a problem with the frogs, all non powered.
Thanks Mel and Betamax! The YT videos that discussed changing polarity with the servo mount did not specify the type of track but did say DCC. Atlas turnouts are not a problem with DCC or with track polarity. Good to hear that powering the frog is not needed!
For the earlier parts of my layout, I used Atlas plastic-frog turnouts and seldom had problems, but they were all short turnouts. As my layout got larger, I began using Walthers turnouts which were longer. They were mostly fine, but I would occasionally get stalling, particularly with short trolleys. Since those turnouts had Tortoises to drive them already, it was pretty simple to power the frogs. I did notice significant improvement when I did that. Now I do it regularly during installation.
