Wiring Atlas o 2 rail switch for DCC help needed

I am not familiar with the "new" atlas switches.    but I am going to guess they are "DCC frienlty".    The means the frog is insulated from the running rails on either end.   It also means that the points on each side are the same polarity/power at the running rail next to them, so a the backs of a metal wheel on a loco or car does not cause a little short when passing through.   You should check the switch out with a continuity meter to see what is wired to what.

There is nothing special to wiring a switch to DCC that is different from wiring for straight DC or AC for that matter.   You do have to be more cautious of potential intermittant shorts from accidental contacts.  

If the frog is indeed insulated as I suspect, it would always be dead.    That should not be a problem for long wheel base locos.   However, it sometimes causes a stall with short wheelbases and slow running.    If you want to power the frog,  you need to use a switch machine with contacts or a micro switch aligned with the throw bar to change the frog polarity when you move the switch points.    The polarity of the frog should always be the same as the closed point.

Jim is correct. The frogs on Atlas switches are insulated. 

I had one where the frog was just touching one of the rails next to it and it caused a short. It took me a while to find it. Just want you to be aware that although unusual I have heard of other people having the same issue.

Also the one real issue I had with my Atlas switches is the point rails get there power from the rail they are touching. If you're using a good switch machine you probably won't have a problem but I had a temporary layout and the points would move slightly and then they were not powered. A guy from the Atlas forum recommended to install a small wire from the powered rail to the point rail. I will do this when I build my next layout. 

Jim and Hudson are on the money. To be truly DCC friendly, you need powered frog (there's a tab on the end of one tie by the frog you can solder to). Also the closure rails would be hard wired to their adjacent stock rails, and you'd have a flexible feeder to the switch rail either from below or jumpered from the closure rail. One thing I fund is that the frog seems to be glued to the tie trip and there's only a small pin connecting to a metal boss underneath to bring the power from the tab. So it may better to solder direct to the frog.

The full monty on DCC friendly with diagram:   http://www.wiringfordcc.com/switches.htm

Of course these days you have the "lazy person's" alternative which is to add keep-alives to your decoders. For the $20-$30 cost, I say money well spent. Especially if you're as lazy as me when it comes to track wiring.     

Some info on keep-alives:   http://www.members.optusnet.co.../mainnorth/alive.htm

BTW This site requires compatibility mode in IE11 and maybe earlier versions.

I'm out in left field with this one.  All of my frogs are dead.  My locos can easily span the dead frogs.  The point rails etc., are all wired with droppers on the bottoms of the feet of the rails.

Where's me tin hat? 

Believe it or not, in the 3-rail world there's a similar problem with larger turnouts but it's on closure rails and the Tortoise machine is the best solution for solving switch continuity/polarity problems.

If you use Tortoise machines, it's  simple process to maintain proper frog polarity. The Tortoise has two sets of SPDT contacts. These are 2,3,4 (4 is common) and 5,6,7 (5 is common). You tie a common to the frog and one of the others to each rail adjacent to the frog and it will power from the adjacent rail the turnout is aligned to. I don't know the current rating of the contacts, but as a practical matter, the current flow is going to be momentary. As I recall, on Atlas turnouts, the closure rails are also "cold" so it might be a good idea to either route their power through the Tortoise machine or power them from the appropriate stock rail -- the Tortoise being the better option in my opinion as it turns off the unused rail. My plan for 2-rail turnouts is to wire the closure rails to the points.

 Just came across this topic and one statement above gave me cause to think.  So, I just ohm'd out an Atlas O 2 rail #7.5 switch not in the layout and on the workbench - with the point rails set in the "middle" not touching either stock rail.  My results show that the stock rail, closure rail and point rail are all wired together and show zero ohms as expected.  And, as stated above, the frog is isolated from all tracks and "dead" making it DCC Friendly.  So, out of the box these Atlas O 2 rail switches can be installed and used as is a long as the engine pickups can span the dead frog. 

Having said that, FWIW I agree with much of what's been said above.  The internal wiring in these switches is iffy and so adding jumpers where you feel it will help if using manual ground throws or doing what Matt says if using Tortoise or other switch machines is a good idea.  And there are the older manual switch methods, too for those that wish to take the low tech route.

Also, I too have had several switches where one of the gaps between the rails and the frog disappears -- over time  from stress and expansion/contraction in the layout -- resulting in a short -- which I chose to fix by widening the gap with my Dremel and just leaving a slightly enlarged air gap.  Other brands use a very thin Teflon insulator which looks better.

Finally, I power my frogs with TAM Valley Depot Frog Juicers which only work with DCC.    Easy to install and work every time.  I'm very pleased with them.  I solder the feeder wire directly to the bottom of the frog and do not rely on the flimsy Atlas O copper extension to one side from the frog.

SPEECH.  There are lots of different products and methods to deal with all aspects of having very reliable switches (including keeping them clean).  The time spent up front getting it right will more than pay off over time.  I would know.  Nothing is more frustrating than one switch with an intermittent electrical problem  -- except multiplying by a dozen or two.    Ask yourself how many times you've been at a great looking layout only to watch engines being nudged across switches or stop dead at one? END OF SPEECH.

Merry Christmas and a big THANKS for all the help! Bruce in Mount Airy, MD