Insulating stock rails on DCC

[Sandy]

Hi. I have a single track layout with a number of passing loops. Everything I've read says you need to isolate both stock and closure rails. I don't understand why. I understand the reason for isolating the closure rails, but I can't see any place in the stock rails where shorts could happen. Can I use a single isolating joiner on both closure rails and a soldered joint on the stock rails?

[betamax]

Not exactly sure what you are asking. Lets start here: DCCWiki-Turnouts

What kind of turnouts are you using?

Usually the stock and closure rail are wired as a pair, as they must share the same phase in DCC.  Their switch rail will also be part of that group.

The problematic issues usually involve the frog, where a short between the wing and point rails can occur, or if the point rails are one unit electrically. The solution there is insulated rail joiners or gaps on the point rails to break that connection with the track past the frog.

 

[richhotrain]

Sandy

Hi. I have a single track layout with a number of passing loops. Everything I've read says you need to isolate both stock and closure rails. I don't understand why. I understand the reason for isolating the closure rails, but I can't see any place in the stock rails where shorts could happen. Can I use a single isolating joiner on both closure rails and a soldered joint on the stock rails? 

If you are trying to isolate the "passing loop" from the mainline, why not just insulate both rails leading into the passing loop?

Rich

[MisterBeasley]

What turnouts are you using, and what do you mean by "passing loop?"

Is this a passing siding where you enter and leave but end up going the same direction, or a reversing loop where you enter the loop and come out going the opposite direction?  The wiring requirements are quite different.

[jjdamnit]

Hello All,

Sandy

Everything I've read says you need to isolate both stock and closure rails.

I'm curious as to where you "read" this; online, magazine, how-to book, etc.?

The reasons to isolate sections of track are to create a power block or district, a reversing loop, or a programming track incorporated into the pike.

Sandy

I have a single track layout with a number of passing loops.

MisterBeasley

...what do you mean by "passing loop?"

I too am confused by your term "passing loops".

"Sidings" are sections of track that run parallel to the "mainline" trackage with turnouts at each end that connect these sections back to the mainline.

I can envision a loop of track, within the main oval, to serve industries or act as a passing siding.

Even this would not necessitate isolating this track in DCC.

With DC I could understand the need to isolate passing sidings, a loop within the main oval, and/or yard(s) to have separate cab control.

Please understand I am not trying to deride your terminology, I am attempting to understand your question by using common definitions.

If you could provide a track diagram this might answer many of the questions needed to help you in your inquiry.

Hope this helps.

[rrinker]

 Passing loop is a UK term for what in the US we would call a passing siding, double ended siding. A 'siding' in UK terms is a single ended stub. We just call them all 'sidings' or sometimes 'spurs' for the single ended ones.

See here: https://en.wikipedia.org/wiki/File:Passing_Loop.png

 

                                --Randy

 

[jjdamnit]

Hello All,

rrinker

Passing loop is a UK term for what in the US we would call a passing siding...

Another example of a common culture divided by the language.

With that clarification, it still begs the question what source(s) is the OP referencing?

Hope this helps.

[selector]

Sandy

Hi. I have a single track layout with a number of passing loops. Everything I've read says you need to isolate both stock and closure rails. I don't understand why. I understand the reason for isolating the closure rails, but I can't see any place in the stock rails where shorts could happen. Can I use a single isolating joiner on both closure rails and a soldered joint on the stock rails?

 

Like the others, I don't follow you with the image my mind feeds me, and it's probably because of the terminology.  I am not aware that a closure rail needs isolation because they flare away at the frog into the frog guards, and 'should be' innocuous, regardless of their stock rail assigned proximity or phase/polarity.  If wheel gauge is a problem, then that's another matter.

I believe that most just isolate the two frog rails, either with a tiny gap or with a small piece of styrene.  There's no need to gap/isolate the stock rails near a siding because they don't swap polarity/phase anywhere.  If you wanted to isolate the rails between the accessing turnouts/points, say to shut power down and part a train there, sure, nothing wrong with that.  But, you'll need a switch in series and to wire the rails at the frog ends of both accessing turnouts.

[gregc]

Sandy

Everything I've read says you need to isolate both stock and closure rails. I don't understand why.  ...  Can I use a single isolating joiner on both closure rails and a soldered joint on the stock rails?

do you mean cut a gap in the closure rail near the frog?

selector

Like the others, I don't follow you with the image my mind feeds me, and it's probably because of the terminology

[RR_Mel]

Greg

Like your gif, saved it for future use.


Mel


 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

[Mark R.]

Lots of speculation. Possibly wait until the OP chimes back in for clarification ? 

Mark.

[richhotrain]

Mark R.

Lots of speculation. Possibly wait until the OP chimes back in for clarification ? 

Mark. 

I agree, Mark. We need to know what he is trying to do and what kind of turnouts he plans to use.

Rich

[snjroy]

Posting a picture of the layout would help.

Simon