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Turnouts and DCC

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  • Member since
    December 2012
  • 13 posts
Turnouts and DCC
Posted by jdv69z on Monday, September 2, 2013 11:49 AM

I've just powered up half my layout including several turnouts. Turnouts are Shinohara/Walthers code 83. I believe frogs are metal and not powered/electrically isolated, thereby eliminating short circuit problems which can occur at the points. Loco's seem to be losing power/ hestitating and restarting across several of the turnouts, Do I need feeders at both ends of the turnouts? My meter indicates contact at various points along the rails, ie zero resistance, so it appears I have continuity?

  • Member since
    January 2010
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Posted by peahrens on Monday, September 2, 2013 3:19 PM

Are these relatively recent W-S code 83 "DCC Friendly" types.  Compare the model numbers with the website if not sure. 

Anyway, if like the ones I purchased last year, your meter will verify infinite resistance between the frog and any other rails.  If you have one not pinned down, look under the ties and you can see the jumpers that connect the three pairs of incoming / outgoing rails, as well as the un-moveable "closure rails" between the frog and points hinges, as you would expect is needed. So, one pair of solid electrical connections at an entry or exit point will power most of the turnout. 

The moving point rails get their juice from contacting the stock rail against which they are thrown (mine are held tight by the spring loaded Tortoise), and (if lucky) via the hinge if it happens to provide consistent continuity (it is not so considered).  The "closure rail" between the points hinge and the frog gets power through the underneath jumpers. 

One occasional problem with these is a bad jumper connection, thus a dead piece of rail.  You can spot this by continuity (resistance) testing each piece to its mates.  Strongly suggest bench checking this before installing.  I did not do that on a bad one, so added an aux feeder wire to that rail.

 

So the other electrical weak points of this type are the unpowered frog and the moving points rails.  Many people power their frogs, which requires the power to switch to the appropriate polarity with the points thrown one way or the other.  A Tortoise has aux contacts that can be used for this.  The need for this depends somewhat on the pickup capability of a loco; e.g., a Big Boy will usually have multiple wheels on powered pieces even without a powered frog, whereas a 0-4-0 may well stumble.  The less often addressed potential issue is the moveable points rails.  Most people do not power them, as that's a bit tricky to wire.  Therefore, one must ensure the points to stock rails contact area is nice and clean (no paint, etc) and that there is good contact tension (e.g., from a Tortoise throw).   I did the frog powering only and have not yet encountered problems (in 18 months) with points rail power consistency..

Here's a related link (if you have earlier versions maybe another page addresses those):

http://www.webring.org/l/rd?ring=modelrailroading;id=13;url=http%3A%2F%2Fwiringfordcc%2Ecom%2Fswitches_walthers%2Ehtm

 

Having said this, suggest verify what you have, then see if any problems tend to particular locos and then note carefully what is moving over what, when the problem occurs. 

You also want to determine whether you have a loss of contact (pickup) or a short.  Some 6-axle diesels, for instance, may have wide wheels that bridge across a narrow rail gap near the frogs and short to the rail it should not be touching.  I have a BLI SD-40 that does this but identifying the point of contact and painting on a bit of insulating clear nail polish on the rail near the pinch point is one way to solve this.

 

Paul

Modeling HO with a transition era UP bent

  • Member since
    July 2006
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Posted by locoi1sa on Monday, September 2, 2013 4:00 PM

How are you throwing the points? Is there any tension against the stock rails? Combine tension on the points and feeders after the frogs. You can not have too many feeders but you can have too few.

            Pete

 I pray every day I break even, Cause I can really use the money!

 I started with nothing and still have most of it left!

  • Member since
    December 2012
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Posted by jdv69z on Monday, September 2, 2013 5:06 PM

Paul, thanks for the input. Yes they are the newest DCC friendly type. The problem might well be with the point rails as most of them are not being held by anything at this time. A few are. I have  checked the underside and see what you are saying about how the power is routed, which is why I didn't expect to have problems. Since the frogs are dead, I don't think it is the wheels contacting both rails at the frog and causing a short .I'm more inclined to think it loss of power. Loco's are 4 axle GP7's which seem to have more trouble than the EM1 steam loco am using as well. I've got so definite ideas now as to how to try to nail this down.

Jim

  • Member since
    April 2002
  • 921 posts
Posted by dante on Monday, September 2, 2013 10:49 PM

Unless you are going to power the frogs with the turnout control, the easiest way to power the frogs is with a Frog Juicer. But first use a short piece of wire temporarily placed on the track connecting a powered rail with a frog wing rail to see if powering the frog really is the problem before going to the trouble and expense. (The wing rails and the frog are electrically connected.)

Dante  

  • Member since
    January 2010
  • From: Chi-Town
  • 7,712 posts
Posted by zstripe on Tuesday, September 3, 2013 7:29 AM

JDV69Z,

Do the turnouts that have a switch machine,or ground throw,to keep the points solid against the stock rails work,okay??If they work,,then that is your problem...

Cheers,

Frank

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