Where to isolate on large loops and wye


Charles Cauble
 

I’ve been installing my layout in isolated sections so that I could prove it with a locomotive. The laddered yard has an auto reverse that also switches the tortoise controlled turnouts. The loop was easy to spot so I was able to wire it. My problem is the upper part of my layout where if I connect the switches there will be a conflict of polarities. I do use frog juicers on all frogs. Any help or suggestions would be greatly appreciated because I’m stumped. Seems like auto reversing would affect other trains on the layout.


Blair
 

Charles

In the DCC world, autoreversing does NOT affect train direction - that is an attribute the locomotive decoders manage internally. The purpose is rather to ensure that the rails have the same phase in block transitions.  The W4DCC website has an excellent section describing the difference.

Also, it will be hard for anyone to advise you about general layout wiring, and the locations that need autoreversers, without a layout schematic - not necessarily reflecting topology, but certainly showing the actual track routing.  If you don't have such a drawing, I'd suggest you create one to help yourself in sorting through the locations that might need reversers.

Blair


Blair
 

Charles

The section I referenced earlier is halfway down this page:

http://www.wiringfordcc.com/intro2dcc.htm

Titled "What happens to a train when the power reverses in an automatic reversing section?"

Blair



wirefordcc
 

All,

Reversing seems to be such a challenge for modelers, I have created a link to it in my website at:

http://www.wiringfordcc.com/intro2dcc.htm#reversing

This link is accessible from the blue header on my website from my home page.  

Reversing will also be a topic in my next column in Model Railroader.

Allan Gartner
Wiring for DCC
DCC Currents


Tim
 

Charles,

I've looked at your track plan (located here: https://groups.io/g/w4dccqa/photo/260783/0?p=Created,,,20,2,0,0)

You've got a lot going on here and it's going to take a bit to get my head around it.

Tim Rumph
Lancaster, SC


Paul O <pomilian@...>
 

Charles, I took a shot at a solution.
Three reverse loops.

Paul O


Blair
 

Tim, Charles

I think I've unfolded it correctly, and I see only one reversing section technically required; however, I think for operations sake, it would be better done as two separate pieces with a long non-reversing section between them.  See sketch "reversing.jpg" and markup "Charles sketch annotated.jpg" in your folder.

Blair


Blair
 

Clarification - the reversing section does not need to include the turnout at E, but must be long enough for your longest train, as does the reversing loop at the bottom, from turnout A to turnout C.

On 2/15/2021 4:39 PM, Blair & Rasa wrote:
Tim, Charles

I think I've unfolded it correctly, and I see only one reversing section technically required; however, I think for operations sake, it would be better done as two separate pieces with a long non-reversing section between them.  See sketch "reversing.jpg" and markup "Charles sketch annotated.jpg" in your folder.

Blair





Paul O <pomilian@...>
 

Charles, I replaced my photo because I had one of the isolators in the wrong location at Rev Loop 1.
Also I cleaned up all of your polarity markings to make my changes a little clearer.
You can re-add your polarity markings and see if you agree with my three reverse loops.
(Covid isolation and a lot of snow outside with nothing better to do.)   ;-)


Steve Haas
 

>>>>> Charles, I took a shot at a solution.
Three reverse loops.  <<<<<

 

I can wire that layout with two reversing _sections_, plus the turntable.

 

Best regards,

 

Steve

 

Steve Haas

Snoqualmie, WA


Blair
 

How about giving us a hint, Steve, as to where you would gap?  Similar to my sketch, or differently?

Blair

On 2021-02-15 22:02, Steve Haas wrote:

>>>>> Charles, I took a shot at a solution.
Three reverse loops.  <<<<<

 

I can wire that layout with two reversing _sections_, plus the turntable.

 

Best regards,

 

Steve

 

Steve Haas

Snoqualmie, WA


Charles Cauble
 

I’m studying and planning how to connect the isolated reversing sections on my layout. One question bothering me is if the section is long and you can’t connect it directly to the bus line, can you split the auto reversing’s two wires and attach them at two different places?


Blair
 

If I understand you, Charles, what I'd advise is connecting the reverser at the center of the reversing section, feeding the reverser from the nearby bus feeding the rest of the track.

Blair


On 2021-02-17 10:53, Charles Cauble wrote:
I’m studying and planning how to connect the isolated reversing sections on my layout. One question bothering me is if the section is long and you can’t connect it directly to the bus line, can you split the auto reversing’s two wires and attach them at two different places?


Don Vollrath
 

Yes you can attach the output wires of an AR until to more than one place within the AR section of track. May help bypass misc poor rail connections, etc. Just make sure you have a consistent rail polarity.

DonV


Tim
 

A couple of things to watch out for
 
1- Don't use one AR for more than one reversing section
2- Don't arrange the track so that you go from one AR directly into another. That will completely confuse and hose things.

Tim Rumph
Lancaster, SC


Charles Cauble
 

Another question regarding a reversing area.  I have a pair of switches that throw after the train goes across the reversing area to accommodate the train as it comes back. The tortoise motors are both controlled by the psx-ar reversing the section.  Is there a way I could throw those switches without running a train through the section?
thanks,  Charles


wirefordcc
 

Hi Charles,

Look at page 20 of the PSX-AR manual.  There is a simple way of causing the turnouts to flip without using your train to do so.

Allan Gartner
Wiring for DCC


Charles Cauble
 

Thanks to all for your help.  I’ve been busy laying track. I also have a PM42 with breakout board to split my layout into 3 or 4 districts.  In the instructions it says the third wire should be a ground wire to a booster.  Since my command station is a 5amp NCE the booster is built in. I don’t know where I should ground it.  It mentions the third wire and Digitrax system. Is it  not needed with NCE?


Blair
 

Charles

Answer - If your booster has a booster common, that's where the PM42 "ground wire" goes; do not 'ground' it.  I'm not an NCE user.  Someone with knowledge of how to common-reference NCE boosters should chip in here.

For further interest, here's some good reading on Commons and Grounds in the DCC world:

https://sites.google.com/site/markgurries/home/technical-discussions/boosters/booster-ground-commons

Blair


Steve Haas
 

The manual for the NCE command station will tell you to connect that “booster common” to one of the screws on the NCE Power Pro (Command station and booster).

 

Best regards,

 

Steve

 

Steve Haas

Snoqualmie, WA

 

 

 

 

 

From: w4dccqa@groups.io <w4dccqa@groups.io> On Behalf Of Charles Cauble
Sent: Monday, February 22, 2021 1:22 PM
To: w4dccqa@groups.io
Subject: Re: [w4dccqa] Where to isolate on large loops and wye

 

Thanks to all for your help.  I’ve been busy laying track. I also have a PM42 with breakout board to split my layout into 3 or 4 districts.  In the instructions it says the third wire should be a ground wire to a booster.  Since my command station is a 5amp NCE the booster is built in. I don’t know where I should ground it.  It mentions the third wire and Digitrax system. Is it  not needed with NCE?