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DC wiring question on a new layout

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Posted by Overmod on Saturday, June 12, 2021 9:30 AM

jjdamnit
Since you are using Atlas controllers I suggest purchasing The Complete Atlas Wiring Book... Unfortunately, it is currently listed as Backorder on the Atlas website.

At least two copies of the 2017 edition of this #12 are currently up on eBay for close to the listed price.  I'm reasonably sure 'used' copies will show up on Amazon or some of the 'discount' book sites from time to time.

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Posted by mikeGTW on Saturday, June 12, 2021 9:29 AM

I forgot all my layouts have been common rail   all with mutiple controllers  

And I have one Y on my layout controlled by relays  

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Posted by ATLANTIC CENTRAL on Saturday, June 12, 2021 9:26 AM

Lastspikemike

Incidentally, it is actually confusing to refer to reversing sections and "main lines" as if these are different electrically. It makes more sense to realize that electrically speaking you automatically create two reversing sections as soon as you create one.

Conceptually this is bad way to view this, because, based on my 50 years of experience, it actually confuses people more.

Yes, you are also reversing the main, but, per my earlier comments, DC operation is much easier for operators to understand if reversing switches are orientated "east - west" relative to physical movement.

Every layout is a little different and may require different solutions, but the ability of an operator to look at a reversing switch and KNOW which way the train will move is a huge advantage.

Since reverse loops typically change that flow, they need a different convention, hence clockwise, counter clockwise.

See, this is why I'm not in these conversations any more.

If the original poster would like some help, he is welcome to send me a PM.

Sheldon

    

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Posted by mikeGTW on Saturday, June 12, 2021 9:24 AM

Kevin he is not going to post any pictures he refuses to do so 

And I totallly agree with CSX Robert  Sheldon and Kevin   

I have been in this since about 1970   worked at real RR for 30 plus yrs in signal dept as lead signalman foreman and tech    So as far as I can see the diag for the 220 is accurate   I don't know what the expert on all things relative to MR thinks is wrong with it but after all he has only been in this for the last two years

He also goes on about his layout (no picts)  and a club  (name ???) 

 

I never used any of the atlas controllers pcs  thought I had some in a junk box can't find them  I use  just their switches   over 100 on my layout   still have a few of the old brass kits new in box  kinda wonder if they changed the brass formula at some point cause those kits are still shiney no corrosion at all

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Posted by SeeYou190 on Saturday, June 12, 2021 9:10 AM

Lastspikemike
The Atlas schematic for the 220 is not accurate as I previously noted. In particular, the circuit to  the "common rail" output from the same polarity input is not shown. To understand my remark you need to understand that...

I cannot follow what you are stating.

Please post a corrected schematic drawing comparing it to the one that Greg showed, and also please include sketches outlining the 220 internal wiring design changes. That way I can understand your explanation.

-Kevin

Wink Happily modeling my STRATTON & GILLETTE RAILROAD. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by Lastspikemike on Saturday, June 12, 2021 8:47 AM

The Atlas schematic for the 220 is not accurate as I previously noted. In particular, the circuit to  the "common rail" output from the same polarity input is not shown. To understand my remark you need to understand that the two reversing switches in the 220 just always be set to center off when ganging the 220's. Terminal C is then not connected in any 220 in the gang except the last one. Describe the line on the schematic that shows how the common rail power flows from either Cab A or B input terminal through the 220 to power the input terminal on the ganged 220. 

The schematic has not been changed but the 220 design has. Only the control rail terminal now carries through by external connectors.  Correction, the original 220 had four inputs which become two outputs. The schematic and the Atlas Wiring book ignore this change except for a written note. That written note does not appear in the Atlas Wiring book. Older 220 have to be used only downstream from the newer design of 220. Perhaps the original 220 could not be ganged. 

The schematic does show that when the C circuit did flow through the ganged 220's that the powerpack connection diagram ls incorrect. The inner of the two input terminals flow though the C common rail connection according to the schematics. That is correct as you will find if you check with a multimeter. The Atlas figure shows the powerpack is connected in series rather than in parallel to the 220. I know that is incorrect because I followed the figure and not the schematic.  If you wire the powerpack according to the figure instead of according to the schematic you will get a dead short. 

I know that the information I posted is correct because I ganged three 220's to feed three "reversing sections" and checked polarity using a multimeter.

Incidentally, it is actually confusing to refer to reversing sections and "main lines" as if these are different electrically. It makes more sense to realize that electrically speaking you automatically create two reversing sections as soon as you create one.

I did not say you cannot use the powerpack reversing switches  I said that you do not. If you do try to use the power pack reversing switches when using the 220 controller you will eventually get confused, I guarantee it. Electrically, there is no difference between using the 220 with 215 selectors and a series of DPDT block control switches except for polarity control. The 220 is quite convenient because it exploits the advantages of common rail wiring. There are disadvatages to common rail noted elsewhere. The major advantage of DCC is elimination of the need for any block control. Except for reversing sections.

I wired up one reversing section to a snap relay to bypass the reversing loop reversing switch and in that case you may need to occasionally manually reverse the reverse polarity within the reversing loop because of that feature. Reversing a train through a reversing loop with "automatic" reversing polarity controlled by the turnout can cause operating issues.

It is amazing how egotistical many posters seem to be about "their way" of describing stuff.  The rest of us idiots should just leave the forum or maybe just tug our forelocks before logging in. Who needs to log in, just read the words from the forum gods.

No comments required.  

Alyth Yard

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Posted by SeeYou190 on Saturday, June 12, 2021 8:23 AM

Lastspikemike
Atlas wiring book page 37 figures 5-6 and 5-7 show incorrect connections from powerpacks to the 220. The 220 packaging diagram is also incorrect.

The wiring diagrams provided by Atlas are correct.

ATLANTIC CENTRAL
I would never recomment anyone use the Atlas system..

Like Sheldon, I would NEVER suggest anyone use the Atlas wiring components.

ATLANTIC CENTRAL
I've been staying out of these DC wiring threads because they are full of questionable or hard to understand advice.

Yes. They always get muddled up by inexperienced people giving bad advice about a subject they do not comprehend.

That is why I deleted my posts about DC reverse loop wiring. The replies full of incorrect information ruined the thread.

Only people that have successfully wired multiple DC layouts, and understand DC control, should be participating in these conversations.

Wink Happily modeling my STRATTON & GILLETTE RAILROAD. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by ATLANTIC CENTRAL on Saturday, June 12, 2021 6:16 AM

gregc

 

 
Lastspikemike
each Cab is given its own reversing switch and the powerpack reversing switches are not used.

 

the powerpack reversing switch can certainly be used on both the mainline and reversing sections

 

I've been staying out of these DC wiring threads because they are full of questionable or hard to understand advice and I don't have the time to sort them out.

But first off, I would never recomment anyone use the Atlas system....

Second, the power pack reversing switches can be used as a "local direction switch" for the cab in question, but it is not really the best approach.

By only using the separate reversing switches established for the mainline and reverse loops, you can establish a protocal where the direction switches are always in the same position relative to the actual direction of travel, best defined as east/west on the main, and clockwise/counter clockwise in reverse loops.

Every time you change the power pack direction switch, you reverse this whole protocal changing everything down stream. Very confusing at best.

As an example, on my DC powered layout I use Aristo wireless throttles. The layout is designed and wired such that if you push the left direction button on the throttle, the train ALWAYS moves to you visual left, etc.

My reverse loops (of which there are just one loop, one wye, and one turntable) are wired in a  semiautomatic fashion which maintains this directional continuity.

My entire layout is designed such that you are always viewing the trains as if you are facing north, left is west, right is east.

This is a distinct advantage for helping operators understand the layout, be they DC or DCC controled, but is a serious advantage on a DC layout direction switches set the direction of travel relative to the track, not the locomotive "front".

Sheldon     

    

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Posted by gregc on Saturday, June 12, 2021 5:15 AM

Lastspikemike
The Atlas 220 Controller is designed to work with common rail

there's no reason the 220 couldn't be used on a non-common rail layout.   they are designed to plug into atlas 215 modules

Lastspikemike
and allows polarity to be reversed for Cab A relative to Cab B,

there's no need to reverse the polarity relative to the other cab.   there is a need to independently control the polarity of both the reversing section and mainline

Lastspikemike
each Cab is given its own reversing switch and the powerpack reversing switches are not used.

the powerpack reversing switch can certainly be used on both the mainline and reversing sections

Lastspikemike
Atlas wiring book page 37 figures 5-6 and 5-7 show incorrect connections from powerpacks to the 220. The 220 packaging diagram is also incorrect.

perhaps you can explain what is wrong with the Atlas wiring using the following diagram we can all see

 

greg - Philadelphia & Reading / Reading

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Posted by CSX Robert on Friday, June 11, 2021 9:03 PM

Lastspikemike
I just quoted what Atlas calls common rail in Chapter 3. They even have a diagram of a simple oval with one power pack, figure 3-1. You have to move on to Chapter 4 before Atlas adds a second Cab (powerpack). So, clearly, there is not a commonly accepted definition of common rail.

I don't have the Atlas book, so I'll take your word for it.  As I said, every discussion I've seen has been about mutliple cab control, but that may just be because when someone has a question about common rail wiring that's usually what they are wanting to do.  Allowing for that it's still a far cry from "all DC layouts are essentially common rail."

Lastspikemike
The Atlas 220 Controller is designed to work with common rail and allows polarity to be reversed for Cab A relative to Cab B, each Cab is given its own reversing switch and the powerpack reversing switches are not used.

The reason the Atlas 220 Controller has direction switches for the cabs is because with a reversing section you want to be able to reverse the cabs separately from the reversing section.  If you were to use the power pack reversing switch, to traverse a loop you have to stop the train in the loop, throw the power pack reversing switch and the loop reversing switch, and then you can proceed out the other end.  With the 220 controller you can throw the cab reversing switch while the train is in the loop and proceed through the loop without stopping.  Without a reversing section you do not need the 220 controller and are free to use the power pack reversing switches.

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Posted by Lastspikemike on Friday, June 11, 2021 5:02 PM

I just quoted what Atlas calls common rail in Chapter 3. They even have a diagram of a simple oval with one power pack, figure 3-1. You have to move on to Chapter 4 before Atlas adds a second Cab (powerpack). So, clearly, there is not a commonly accepted definition of common rail.

The Atlas 220 Controller is designed to work with common rail and allows polarity to be reversed for Cab A relative to Cab B, each Cab is given its own reversing switch and the powerpack reversing switches are not used.

Atlas diagram shows all the positive powerpack terminals connected to the same polarity and only the negative terminals go to the control rails. Or maybe the opposite since DC doesn't care which way the current flows around the circuit. Atlas doesn't label their diagrams with positive and negative until they start discussing reversing sections when current direction relative to the rest of the layout becomes important.

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Posted by CSX Robert on Friday, June 11, 2021 3:56 PM

richhotrain
But I always thought that Common Rail was a well defined method of wiring...

It is, at least for the 35+ years I've been model railroading every discussion of common rail wiring I've seen has refered to the same thing.  "Common rail" wiring refers to a method of wiring a layout for multiple cab control where one rail and one terminal of each cab is wired to a common point.  It doesn't refer to the  number of feeders, the common rail can have one or a hundred and more, it's still "common rail wiring" if those feeders all tie into the same common point with the cabs.  A single cab DC layout is not "common rail" wiring. Sure there is a common left rail and a common right rail, so some people may call that a common rail layout, but without having one of the rails tied into a common connection between two or more cabs, it is not "common rail" wiring as generally understood in model railroading parlance.  Even if that single cab layout has multiple blocks that can be switched on or off through a single pole switch, it still would not generally be considered a "common rail" layout.  What distinguishes "common rail" wiring is that common connection between the cabs.

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Posted by RR_Mel on Friday, June 11, 2021 3:30 PM

Rich

Common rail is just what its name says, there is one rail common through out the layout.  In DCC both rails are common.  The reason I don’t like or use common rail is it ties the direction of the DC locomotives locomotive to the same direction.  

By using two separate power packs one can operate a DC locomotive in each direction but that requires one power pack to be connected positive to negative on the common rail.
 
I prefer to individually control the track polarity for each block individually, in both DC and DCC modes.  

Back when I was learning two rail power vs. Lionel three rail I decided it was easier to switch both rails when controlling my layout.  Even as a teenager connecting the positive terminal of one power pack to the negative of the second power pack didn’t sound like the way to operate two trains.

That was a decision of an early teenager and after 49 years and 10 months working in the electronics field nothing change even a little bit.

Like I said it’s strictly my preference to switch both rails rather than take a chance of crossing the voltages of two power packs.  I like the no brainer approach.

Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
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Posted by richhotrain on Friday, June 11, 2021 2:57 PM

Lastspikemike

"Common rail" does not have a fixed definition.  Atlas Complete Wiring book describes common rail as a system with only one rail being gapped for electrical control.  That allows two or more cabs to be conveniently connected without doubling up all the block wiring but only blocks are needed to create a common rail system. One powerpack will do. As is commonly accepted.   

Oh well, I give up. I don't care anyhow because I am a DCC user. But I always thought that Common Rail was a well defined method of wiring as opposed to two rail wiring.

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Posted by richhotrain on Friday, June 11, 2021 2:26 PM

gregc
richhotrain
A lot of the replies seem contradictory to one another. 

can you site a specific example.  i only see confusing lengthy replies that may be self-contradictory

greg, I cannot believe that it is not obvious to you. The thread is littered with one guy saying this is fact and I am right, while the next guy says you are wrong and I am right. No, I am right and you are wrong.

Read back through the thread, and you will see what I am talking about. Who is to decide who is right and who is wrong? It renders the thread useless in my opinion.

Rich

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Posted by Lastspikemike on Friday, June 11, 2021 2:11 PM

richhotrain

I am a  DCC user, so I have no skin in this game. But, when the thread started out, I tried to follow along to see if I could learn something about DC block wiring and common rail.

But, at this point, this thread has become useless because of so many contradictory statements. Somebody must be right, and somebody must be wrong. Is there any way to sort this all out in order to salvage this thread?

Rich

 

Not necessarily. "Common rail" does not have a fixed definition.  Atlas Complete Wiring book describes common rail as a system with only one rail being gapped for electrical control.  That allows two or more cabs to be conveniently connected without doubling up all the block wiring but only blocks are needed to create a common rail system. One powerpack will do. As is commonly accepted.  

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Posted by gregc on Friday, June 11, 2021 1:31 PM

CSX Robert
I just meant that in the reversing section, one of the rails is still going to be electrically common with the "common" rail of the rest of the layout

right, and of course.   thanks

richhotrain
A lot of the replies seem contradictory to one another.

can you site a specific example.  i only see confusing lengthy replies that may be self-contradictory

Atlas has proven that common-rail works.

greg - Philadelphia & Reading / Reading

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Posted by CSX Robert on Friday, June 11, 2021 10:38 AM

gregc
not sure if this is what you mean that the reversing sections are (or can be) common rail

I just meant that in the reversing section, one of the rails is still going to be electrically common with the "common" rail of the rest of the layout although you have to be able switch which rail that is.

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Posted by richhotrain on Friday, June 11, 2021 10:30 AM

A lot of the replies seem contradictory to one another. As I said, somebody must be right and somebody must be wrong.

Rich

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Posted by gregc on Friday, June 11, 2021 10:27 AM

richhotrain
Is there any way to sort this all out in order to salvage this thread?

what do you find confusing?

greg - Philadelphia & Reading / Reading

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Posted by gregc on Friday, June 11, 2021 10:25 AM

CSX Robert
These sections are actually still common rail, but you have to be able to switch witch rail is the common rail depending on which end of the section you are traversing.

i don't believe there are any restrictions in having multiple blocks within a reversing section allowing trains being operated by separate cabs.   

the power for those blocks would go thru the reversing section reversing switch.

not sure if this is what you mean that the reversing sections are (or can be) common rail

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Posted by richhotrain on Friday, June 11, 2021 10:24 AM

I am a  DCC user, so I have no skin in this game. But, when the thread started out, I tried to follow along to see if I could learn something about DC block wiring and common rail.

But, at this point, this thread has become useless because of so many contradictory statements. Somebody must be right, and somebody must be wrong. Is there any way to sort this all out in order to salvage this thread?

Rich

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Posted by CSX Robert on Friday, June 11, 2021 10:13 AM

Lastspikemike
Things get a bit more complicated when you add a second power pack to a DC system in that you have to make sure you connect the red wires and the black wires correctly to the second powerpack (duh).

You have to have at least two power packs to have a "common rail" layout.

A layout with a single power pack and isolated sections that can be turned on and off is not a "common rail" layout - you could call it that if you want, but in accepted model railroading parlance that is not correct.  "Common rail" specifically refers to a method of wiring cab control where you have more than one cab (or power pack), and you have a common connection both between the cabs and one rail of the layout.

One thing that is confussing for some is that with common rail wiring you do not have to have the "+" of one cab wired to the "+" of the other.  This means that you can switch directions of the cabs independently, so with a properly wired common rail layout you have independent control of speed and direction of the blocks.  A "reversing section" on a common rail layout refers to a section of track where the "A" and "B" rails swap, such as a reversing loop or wye.  These are the sections that need to be double isolated - not to give directional control of the trains but to prevent the "A" and "B" rails from shorting out to each other.  These sections are actually still common rail, but you have to be able to switch witch rail is the common rail depending on which end of the section you are traversing.

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Posted by gregc on Friday, June 11, 2021 10:12 AM

Lastspikemike
Things get a bit more complicated when you add a second power pack to a DC system in that you have to make sure you connect the red wires and the black wires correctly to the second powerpack.

doesn't matter.   cab power needs to be reversible

Lastspikemike
Much of the confusion about reversing loops is caused by incomplete understanding of common rail wiring.

and unnecessary described constraints (see above)

 

power can be switched between cabs using an SPDT for common rail blocks and using DPDT for switching between cabs in reversing sections.

regardless of common rail or not, there is a potential for a short at the sum of both cab voltages.

and of course, things need to be wired properly.

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Posted by CSX Robert on Friday, June 11, 2021 9:32 AM

Lastspikemike
My point is that even double isolated blocks will be common rail unless you also switch power on and off to both rails (and of course use reverse polarity switching for reversing sections). I know. I wired one. All the red rails on my double isolated DC layout are connected together by bus bars under the layout.

If the rails are tied together under the layout, then they are not isolated, if they are isolated, then it is not common rail.

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Posted by Lastspikemike on Friday, June 11, 2021 9:20 AM

CSX Robert

 

 
Lastspikemike
Adding bus wires and feeders doesn't make it not common rail wiring. Cutting power to only one rail is what makes a system "common rail" straight toy speaking. For DCC you don't need a "control rail", Bith rails are common rails. It's the addition of double isolating blocks that does break up the common rail(s)  wiring system...

 

It looks like you added this while I was replying.  If you understand that double isolating the blocks breaks up the common rail wiring, then how do you come to the conclusion that " all DC layouts are essentially common rail."

 

 
Lastspikemike
You need to do that only if you add power boosters in DCC or want full electrical control of your DC blocks. 

 

Again not true, with common rail wiring you have full electrical conrol of the DC blocks.

 

I know you are missing my point. It doesn't matter. You understand common rail and so do I. Common rail would have been more accurately named "control rail" since it is the electrical control of the blocks by isolating gaps in only the one rail that makes it a common rail "system". Electrically, a common rail is a rail powered with one electrical source for its entire length. The return rail is akso a common rail if it meets that definition.  

My point is that even double isolated blocks will be common rail unless you also switch power on and off to both rails (and of course use reverse polarity switching for reversing sections). I know. I wired one. All the red rails on my double isolated DC layout are connected together by bus bars under the layout. Why? So I can easily connect a DCC power booster to the entire layout but still retain the option of running block control DC. I can add polarity reversing capability to any block by disconnecting the red wire at the appropriate bus bar and connecting it to a DPDT instead.

Much of the confusion about reversing loops is caused by incomplete understanding of common rail wiring.

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Posted by CSX Robert on Friday, June 11, 2021 9:15 AM

Lastspikemike
Adding bus wires and feeders doesn't make it not common rail wiring. Cutting power to only one rail is what makes a system "common rail" straight toy speaking. For DCC you don't need a "control rail", Bith rails are common rails. It's the addition of double isolating blocks that does break up the common rail(s)  wiring system...

It looks like you added this while I was replying.  If you understand that double isolating the blocks breaks up the common rail wiring, then how do you come to the conclusion that " all DC layouts are essentially common rail."

Lastspikemike
You need to do that only if you add power boosters in DCC or want full electrical control of your DC blocks. 

Again not true, with common rail wiring you have full electrical conrol of the DC blocks.

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Posted by Lastspikemike on Friday, June 11, 2021 9:09 AM

I'm not confused. The idea of common rail confuses people because it seems to involve some of the things you describe. It doesn't.

A toy train uses common rail power. A DC or DCC system with control rail gaps is common rail. Add just one reversing section and you no longer have a common rail system.

Too many people don't understand common rail because of the way it is described. It's just toy train wiring. 

Things get a bit more complicated when you add a second power pack to a DC system in that you have to make sure you connect the red wires and the black wires correctly to the second powerpack (duh). You really don't want to do that if you add a second power booster to a DCC layout. In fact, there are good reasons not to use full common rail wiring when building a DC layout but electrically your DC layout will still be common rail even if double isolated unless you also control your blocks with DPDT instead of SPDT which you forgot to mention. 

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Posted by CSX Robert on Friday, June 11, 2021 9:04 AM

Lastspikemike
I look at the wiring and the tracks. It's correct. Your perspective may disguise the reality. Layout wiring is pretty simple stuff. Red wire to one rail, black wire to the other rail.  In fact, one huge advantage of DCC is you can just hook up two wires to one connection track and your whole layout will be powered for multiple locomotive operation. Two common rails. No bus wires at all. Don't mention reversing sections. They don't work with common rail at all. DCC or DC.

I think maybe you're confused about what common rail wiring is.  Take a DC layout with two blocks (to really be useful you need more than two bloacks, but this is just for demonstration), two cabs, and two trains running - block 1 switched to cab 1 and block 2 switched to cab 2.  With normal (not common rail) wiring, you have cab 1 output A wired to block 1 rail A, cab 1 output B wired to block 1 rail B,  cab 2 output A wired to block 2 rail A, cab 2 output B wired to block 2 rail B.  Within each block you may have one feeder wire per rail or you may have a dozen, it doesn't matter.  You have two isolated circuits - there is nothinig common between them - there is no way this could be described as a common rail layout.

 

Now, if you wire cab 1 output A and cab 2 output A together and remove all of the isolating gaps between the blocks in rail A, but leave them in rail B, you have a common rail layout.  It doesn't matter if you have one feeder or 100 for the common rail, it's still common rail because that entire rail is common and tied back to the common outputs from the two (or more) power packs.

 

Lastspikemike
Don't mention reversing sections. They don't work with common rail at all. DCC or DC.

Common rail doesn't work with reversing sections, but you can certainly have reversing sections on a common rail layout, you just have to have the reversing section completely isolated.  It's still considered a common rail layout because the rest of the layout is common rail.

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Posted by Lastspikemike on Friday, June 11, 2021 8:38 AM

CSX Robert

 

 
Lastspikemike
...The only way common rail is different to standard DC or DCC two wire bus wiring is common rail relies on the rail only to feed current to one side of the circuit...

 

No, the way common rail is different is one rail is electrically common throughout the layout (except for reversing sections if the layout has any).  Most larger common rail layouts use multiple feeders for the common rail instead of relying on just the rail for feeding current to the common side of the circuit - they are still "common rail" layouts because they still use an electrically common rail.

 

 
Lastspikemike
...although all DC layouts are essentially common rail no matter what people say about how theirs isn't...

 

I don't know how you came about this idea but it's simply not true.

 

 

I look at the wiring and the tracks. It's correct. Your perspective may disguise the reality. Layout wiring is pretty simple stuff. Red wire to one rail, black wire to the other rail. 

In fact, one huge advantage of DCC is you can just hook up two wires to one connection track and your whole layout will be powered for multiple locomotive operation. Two common rails. No bus wires at all.

Adding bus wires and feeders doesn't make it not common rail wiring. Cutting power to only one rail is what makes a system "common rail" straight toy speaking. For DCC you don't need a "control rail", Bith rails are common rails.

It's the addition of double isolating blocks that does break up the common rail(s)  wiring system. You need to do that only if you add power boosters in DCC or want full electrical control of your DC blocks. 

Don't mention reversing sections. They don't work with common rail at all. DCC or DC. (Oops, you did already) 

Alyth Yard

Canada

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