# block wiring a new layout



## Les (Feb 11, 2008)

I'm getting closer to laying track, been reading.
 
I note there's a method of wiring called 'common rail', which means one rail (apparently the inside one) is considered 'common' or 'ground' in electrical terms--of which I'm familiar. I instantly saw the advantages of this method, but what are the pitfalls, if any? My layout will be PP.
 
Also, this question's been bugging me for a year: Gaps in the track rail. So that one 'block' can be isolated from the next. I get it, that far. Now, what happens when a metal wheel momentarily bridges that gap, and let us suppose the 'hot rail' or the outside one (from question above) happens to be set accidentally to the 'reverse' direction? Am I missing something pretty basic, here? Are there electrical lockouts or signals? or should there be? I don't mind installing signals to indicate 'hot' track. I am inclined against electronic circuitry. (Don't want to fool with it). Which promotes another question: using 'track polarity reversing' to change directions, how can one also have 'common rail'?
 
Also, suppose the following scenario: I am puddling along in my Critter, dragging a couple of skips. I leave Block 1 and enter Block 2, which is A) either dead, or B) energized in the proper direction/polarity. If A, the engine stops. (Assume all plastic wheels and slider shoe pickups, it's simpler). If B, it continues on and all is well. Thus, is it good practice to set all the electrical switches along a chosen route First, or set them as the train approaches? This is a relevant question, because my layout will be subdivided into areas where I will physically move to control things locally, so to speak. I envision all the electrical circuitry and controllers to be confined to the trackside structures and track for that area alone.
 
Thanks,
 
Les


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## steam5 (Jun 22, 2008)

Les,

I recommend you pick up a wiring information book from your local hobby shop for a read.

It short to answer your questions, common rail has no pit falls; it works fine for normal DC and also DCC.

Regarding the rail joint, a metal wheel bridging this joint will not do anything all. What will happen is if a block is turned off and its adjacent is on, the metal wheel will liven the block.

To reverse the loco you switch the polarity of the track. Common in this case refers to the rail; all common rails are electrical connected. When you switch the polarity to change direction it will swap the power from the common rail to the other side, so the polarity of the common rail changes as well.

Hope this helps you out.


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## DKRickman (Mar 25, 2008)

Posted By steam5 on 11/05/2008 7:09 PM
It short to answer your questions, common rail has no pit falls; it works fine for normal DC and also DCC.



This is not 100% accurate. Common rail wiring is not reccomended for DCC, although it can work if done properly. The big problem is that some DCC boosters are internally grounded with the 120VAC wiring, and share that ground with one of their outputs. Connecting two through a common rail system can potentially cause a closed circuit being fed by both boosters, doubling the voltage. This has a habit of frying things, which can be somewhat frustrating, to say the least.

Boosters are available with no electrical connection between their input and output, and plenty of people have converted a common rail layout to DCC without issue. But, it CAN be a problem in some cases.


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## Greg Elmassian (Jan 3, 2008)

Les, you are not missing something, if you have 2 adjacent blocks at opposite polarity, wheels bridging a gap between blocks will INDEED cause a momentary short circuit. 

Also, if you are using DC, you would need, I believe, separate power supplies to reverse just one block if you had common rail. All of these wiring questions are exactly like the other scales, so as steam5 recommended, perhaps reading a book, that can explain all these concepts in detail would help. 

Personally, if I was doing this, I would not use common rail and gap both rails, it makes some of the wiring simpler. 

Also, certain DCC systems do not work well or at all with common rail, although the one I use works. 

How your system would tolerate this, and how it would affect other trains running from the same power supply would depend on a lot of things. Basically you do not want this to happen. 

With all the advanced methods of train control available to you, and the difficulties of running individual power to separate blocks and powering them, and separate power supplies, and reversing switches, I'm wondering why you are thinking of this way of controlling your layout? 

Regards, Greg


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## toddalin (Jan 4, 2008)

Posted By Les on 11/05/2008 6:25 PM
I'm getting closer to laying track, been reading.

I note there's a method of wiring called 'common rail', which means one rail (apparently the inside one) is considered 'common' or 'ground' in electrical terms--of which I'm familiar. I instantly saw the advantages of this method, but what are the pitfalls, if any? My layout will be PP.

Also, this question's been bugging me for a year: Gaps in the track rail. So that one 'block' can be isolated from the next. I get it, that far. Now, what happens when a metal wheel momentarily bridges that gap, and let us suppose the 'hot rail' or the outside one (from question above) happens to be set accidentally to the 'reverse' direction? Am I missing something pretty basic, here? Are there electrical lockouts or signals? or should there be? I don't mind installing signals to indicate 'hot' track. I am inclined against electronic circuitry. (Don't want to fool with it). Which promotes another question: using 'track polarity reversing' to change directions, how can one also have 'common rail'?

Also, suppose the following scenario: I am puddling along in my Critter, dragging a couple of skips. I leave Block 1 and enter Block 2, which is A) either dead, or B) energized in the proper direction/polarity. If A, the engine stops. (Assume all plastic wheels and slider shoe pickups, it's simpler). If B, it continues on and all is well. Thus, is it good practice to set all the electrical switches along a chosen route First, or set them as the train approaches? This is a relevant question, because my layout will be subdivided into areas where I will physically move to control things locally, so to speak. I envision all the electrical circuitry and controllers to be confined to the trackside structures and track for that area alone.

Thanks,

Les



The common rail can be either inside or outside. Makes no difference, but once you pick one, you have to follow suit throughout your track work.

Advantage is that it saves you about half the wiring for you track feeds. But, you can also use it for all of your lights and accessories, including turn-outs. That's what I do. I feed four different dc and two ac circuits though my common rail with no problems.

Another advantage is that the rail represents a really FAT wire (i.e., low loss over distance).

If you set up your blocks with dpdt center off toggles (most common way to do it) and use two transformers and the train is on one block being controlled by one transformer and transistions onto the next block that is under control of the other transformer..., if they are set with their polarity the same way, it is not a problem. If they are set opposite, one (or both) will pop their fuse/circuit breaker when the train shorts them together. 

Changing directions is accomplished exactly the same as without a common rail. If you have two transformers and one is set one way and the other is set to go the other way and you use a common rail, this is not a problem and BION all of the electrons find their way back to the proper transformer. I recognize that this is hard to fathom and you will have to take it on faith that it does work this way. (Many people have a problem with this concept, me included at first.)

I run with 23 blocks and a common rail. I run as many as 7 train at once on three transformers (four on loops and three p-t-p). Because I run a common rail and have integrated three reversing units right into my control panel, I can even do p-t-p between any two facing sidings on the railroad without double gapping the rails.

Nice to see someone getting into old fashion means of control. Welcome!

If you have other questions in this area, sing out


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## up9018 (Jan 4, 2008)

Les, 

Block wiring is simple, but before you decide how to do it, you must answer a couple of questions. 1) How many trains do you plan on running at one time? and 2) How many power packs do you plan on using? 


If you plan on running more than one train, then don't go with the common rail method as it would prevent running them in opposite directions. Instead cut both rails to create your block. 

Now let's talk about wiring, assume you are using one power pack there should be 2 outgoing wires for track power, for now we will say one is red, the other is black. (BTW, always use 2 colors of wire to keep them separated) Now, you will need 1 toggle switch for each block, these need to be DPST (Double Pole Single Throw) switches. You can get them at Radio Shack, just make sure they will handle your voltage and amperage. (FYI....Double Pole means you can hook both wires to it, Single Throw means it only works in one direction, basically and ON/OFF switch.) Take the red wire, hook it to one post on the input side of the switch, hook the black wire to the other post on the input side of the switch. On the output side, hook a red wire the post on the same side of the switch as the input red wire, and run it to the outside rail of the track, do the same for the black wire and hook it to the inside rail. You will need to do this for each block. Now simply to run in a block, you simply set the switch to the ON position and the block is powered. Use the direction switch on the power pack to set the direction. Now if you plan on moving from one block to another, you simply set both switches to ON, the power pack has the direction set and you will not need to worry about polarity problems. And the beauty is, if all you want to do one day is just run around, you can turn all the switches to ON, and just run around. 

If all of this sounds confusing, let me know and I will try to be more helpful. If you need more help, or a drawing on how to wire let me know. BTW, I design electric forklifts for a living, and have a lot of wiring knowledge. 

Chris


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## toddalin (Jan 4, 2008)

Posted By up9018 on 11/05/2008 8:44 PM
Les, 

Block wiring is simple, but before you decide how to do it, you must answer a couple of questions. 1) How many trains do you plan on running at one time? and 2) How many power packs do you plan on using? 


If you plan on running more than one train, then don't go with the common rail method as it would prevent running them in opposite directions. Instead cut both rails to create your block. 

Now let's talk about wiring, assume you are using one power pack there should be 2 outgoing wires for track power, for now we will say one is red, the other is black. (BTW, always use 2 colors of wire to keep them separated) Now, you will need 1 toggle switch for each block, these need to be DPST (Double Pole Single Throw) switches. You can get them at Radio Shack, just make sure they will handle your voltage and amperage. (FYI....Double Pole means you can hook both wires to it, Single Throw means it only works in one direction, basically and ON/OFF switch.) Take the red wire, hook it to one post on the input side of the switch, hook the black wire to the other post on the input side of the switch. On the output side, hook a red wire the post on the same side of the switch as the input red wire, and run it to the outside rail of the track, do the same for the black wire and hook it to the inside rail. You will need to do this for each block. Now simply to run in a block, you simply set the switch to the ON position and the block is powered. Use the direction switch on the power pack to set the direction. Now if you plan on moving from one block to another, you simply set both switches to ON, the power pack has the direction set and you will not need to worry about polarity problems. And the beauty is, if all you want to do one day is just run around, you can turn all the switches to ON, and just run around. 

If all of this sounds confusing, let me know and I will try to be more helpful. If you need more help, or a drawing on how to wire let me know. BTW, I design electric forklifts for a living, and have a lot of wiring knowledge. 

Chris


Chris, this is not confusing but you have it wrong (at least how it is usually done).

Yes you can run trains in opposite directions on different blocks using different transformers with  a common rail. I do it all the time.

Next, you do not use dpst switches, you use single pole double throw center off toggle switches. From the two power packs, wire the black wires together then to the common rail (or run both to the common rail, same thing). Run one red wire to an outter connection on the toggle. Wire the other red to the far side of the toggle. Now wire the center of the toggle to the track for that block. This is the proper way to do it.


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## Guest (Nov 6, 2008)

i did use common ground with blocks and various transformers. - but only on fully automated layouts. 
by my experience, a block, that temporaryly shall have reversed current, may not be included in the common ground. 

on a simple analogue layout, i used a one track circle with sidings at stations for bi-directional traffic. (i just interchanged the cables to the motors of half of the locos) 
using three transformers (slow-, medium- and fast) i connected all station-tracks to slow, a little farther out to medium and in open country the fast track. 
reedcontacts for turning on the "dead" rails,to start the trains, where the longest strech between stations reaches the next siding. 

the advantage of the common ground was, that i had one thick cable below the layout, where i connected all "left" rails with short cables and connected the "left" out-connectors of all three transformers. 
the "right" out-connectors of each transformer i connected to each "right" rail of the same speed. 

for this basic design there were no switchmotors needed. the trains did cut open the switches at leaving the stations. (the switches fell back to default) 
accidents could happen only by uncoupled cars. only other failures now and then were burnt-out reedcontacts. 

not understanding much about electrics (let alone electronics) i built everything by trial and error. including some additional gimmicks like alternating trains and another circuit, using partly the same rails. 

korm 
.


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## Torby (Jan 2, 2008)

For plain DC, a common rail works well *if* your throttles are powered by separate power supplies. 

Since somebody has to say it,









Forget wiring and mount a battery and RC throttle on the train. In my first battery experiment I wired in a switch so I could switch back to track power. I never switched it back and later ripped out the track pickups.


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## Les (Feb 11, 2008)

Posted By Greg Elmassian on 11/05/2008 8:12 PM
Les, you are not missing something, if you have 2 adjacent blocks at opposite polarity, wheels bridging a gap between blocks will INDEED cause a momentary short circuit. 

/// I thought that'd be the case.

Also, if you are using DC, you would need, I believe, separate power supplies to reverse just one block if you had common rail. All of these wiring questions are exactly like the other scales, so as steam5 recommended, perhaps reading a book, that can explain all these concepts in detail would help.

/// Weelll... every darn book I've EVER bought concerning 'how-to' leaves a lot of tiny little details out. The devils are in the details, the Chinese proverb has it. 

Personally, if I was doing this, I would not use common rail and gap both rails, it makes some of the wiring simpler. 

/// Since that was my fall-back option, I've ever so glad you recommend it.







That's what I had in mind until I happened across a 'common rail' article in an old NG&SL mag. I think--I haven't actually sat down and drawn anything out--that I can build a portable TRACK ONLY power supply to plug between blocks, which will be physically separated. But if I have to, I'll make independent TRACK p/s's. Note that for trackside structures, lighting, animation, etc, I will certainly use dedicated power supplies.

A further detail: I will be building in sections (modules, but not transportable). Thus, wiring can be done in stages.

How your system would tolerate this, and how it would affect other trains running from the same power supply would depend on a lot of things. Basically you do not want this to happen.

/// I there will not be more than one 'hot' engine at any one time, except when my son is over.

With all the advanced methods of train control available to you, and the difficulties of running individual power to separate blocks and powering them, and separate power supplies, and reversing switches, I'm wondering why you are thinking of this way of controlling your layout? 

/// In a word, $$$. DC track control is cheaper, and I understand it (despite the first post I made.)









Thanks for taking time to reply.

Les

Regards, Greg


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## Les (Feb 11, 2008)

The common rail can be either inside or outside. Makes no difference, but once you pick one, you have to follow suit throughout your track work.

Advantage is that it saves you about half the wiring for you track feeds. But, you can also use it for all of your lights and accessories, including turn-outs. That's what I do. I feed four different dc and two ac circuits though my common rail with no problems.

Another advantage is that the rail represents a really FAT wire (i.e., low loss over distance).

If you set up your blocks with dpdt center off toggles (most common way to do it) and use two transformers and the train is on one block being controlled by one transformer and transistions onto the next block that is under control of the other transformer..., if they are set with their polarity the same way, it is not a problem. If they are set opposite, one (or both) will pop their fuse/circuit breaker when the train shorts them together. 



Changing directions is accomplished exactly the same as without a common rail. If you have two transformers and one is set one way and the other is set to go the other way and you use a common rail, this is not a problem and BION all of the electrons find their way back to the proper transformer. I recognize that this is hard to fathom and you will have to take it on faith that it does work this way. (Many people have a problem with this concept, me included at first.)

I run with 23 blocks and a common rail. I run as many as 7 train at once on three transformers (four on loops and three p-t-p). Because I run a common rail and have integrated three reversing units right into my control panel, I can even do p-t-p between any two facing sidings on the railroad without double gapping the rails.

Nice to see someone getting into old fashion means of control. Welcome!

If you have other questions in this area, sing out

'BION'? Uh... what's that mean? 

Right off the top of my head, I DON"T see how you can have two DC power supplies, both of which are reversible, and one common wire. I'll sit down and think about it.

Thanks for the encouragement. Old ways aren't necessarily the worst ways to go. Just look at the diesel/steam controversy still simmering in back corners.

Thanks for the input.

Les


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## Les (Feb 11, 2008)

Posted By up9018 on 11/05/2008 8:44 PM
Les, 

Block wiring is simple, but before you decide how to do it, you must answer a couple of questions. 1) How many trains do you plan on running at one time? and 2) How many power packs do you plan on using? 

Chris,

I plan on using one p/s per block for TRACK ONLY control. I plan to run one train only in any given block. I will be running small engines, critters and 0-4-0's. Low current, in other words.


If you plan on running more than one train, then don't go with the common rail method as it would prevent running them in opposite directions. Instead cut both rails to create your block.

///Good to know this. Wonder why that article didn't point that minor drawback out? 

Now let's talk about wiring, assume you are using one power pack there should be 2 outgoing wires for track power, for now we will say one is red, the other is black. (BTW, always use 2 colors of wire to keep them separated) Now, you will need 1 toggle switch for each block, these need to be DPST (Double Pole Single Throw) switches. You can get them at Radio Shack, just make sure they will handle your voltage and amperage. (FYI....Double Pole means you can hook both wires to it, Single Throw means it only works in one direction, basically and ON/OFF switch.) Take the red wire, hook it to one post on the input side of the switch, hook the black wire to the other post on the input side of the switch. On the output side, hook a red wire the post on the same side of the switch as the input red wire, and run it to the outside rail of the track, do the same for the black wire and hook it to the inside rail. You will need to do this for each block. Now simply to run in a block, you simply set the switch to the ON position and the block is powered. Use the direction switch on the power pack to set the direction. Now if you plan on moving from one block to another, you simply set both switches to ON, the power pack has the direction set and you will not need to worry about polarity problems. And the beauty is, if all you want to do one day is just run around, you can turn all the switches to ON, and just run around.

/// Layout will be PP. I don't get much out of watching trains run 'round. (Genetic defect, prob'ly). 

If all of this sounds confusing, let me know and I will try to be more helpful. If you need more help, or a drawing on how to wire let me know. BTW, I design electric forklifts for a living, and have a lot of wiring knowledge. 

I've done some wiriing too, over the years, nothing particularly complicated. My fall-down area is, I've never run DC track power. I'm just about dead certain I'll stay with 'blocks' of two isolated rails, rather than common rail.

Thanks for taking time to reply.

Les

Chris


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## Les (Feb 11, 2008)

Korm,

I want to avoid reed switches, relays, transistorized gizmos and whatnot, if at all possible, even at the cost of having a train stop until I can physically move over to the dead block and activate it.

I understand polarity (except for the above discussion on common-rail two-transformer control) but I don't care much for it. I'd rather focus my energies on the mechanics, etc. (Ye Gads, I sound like those folk who don't want to put money in a drill press instead of a locomotive!) Sigh.









Thanks for the comments.

Les


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## Les (Feb 11, 2008)

Posted By Torby on 11/06/2008 7:08 AM
For plain DC, a common rail works well *if* your throttles are powered by separate power supplies. 

Since somebody has to say it,









Forget wiring and mount a battery and RC throttle on the train. In my first battery experiment I wired in a switch so I could switch back to track power. I never switched it back and later ripped out the track pickups.

Torby:

I spent a year studying battery and R/C. Here's my personal conclusion: Too many drawbacks, Too expensive, and it diverts time (electronics installation/trouble-shooting) from doing thing I like to do. Expense: transmitters, onboard decoder units, batteries, chargers, and misc. fiddling around. The un-advertised necessity of (sometimes) having to have a battery car.

If my layout were outside, I'd probably go that route. It isn't, and I ain't.









Thanks for the opinion, howsumever.

Les


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## toddalin (Jan 4, 2008)

Posted By Les on 11/06/2008 8:20 AM




The common rail can be either inside or outside. Makes no difference, but once you pick one, you have to follow suit throughout your track work.

Advantage is that it saves you about half the wiring for you track feeds. But, you can also use it for all of your lights and accessories, including turn-outs. That's what I do. I feed four different dc and two ac circuits though my common rail with no problems.

Another advantage is that the rail represents a really FAT wire (i.e., low loss over distance).

If you set up your blocks with dpdt center off toggles (most common way to do it) and use two transformers and the train is on one block being controlled by one transformer and transistions onto the next block that is under control of the other transformer..., if they are set with their polarity the same way, it is not a problem. If they are set opposite, one (or both) will pop their fuse/circuit breaker when the train shorts them together. 



Changing directions is accomplished exactly the same as without a common rail. If you have two transformers and one is set one way and the other is set to go the other way and you use a common rail, this is not a problem and BION all of the electrons find their way back to the proper transformer. I recognize that this is hard to fathom and you will have to take it on faith that it does work this way. (Many people have a problem with this concept, me included at first.)

I run with 23 blocks and a common rail. I run as many as 7 train at once on three transformers (four on loops and three p-t-p). Because I run a common rail and have integrated three reversing units right into my control panel, I can even do p-t-p between any two facing sidings on the railroad without double gapping the rails.

Nice to see someone getting into old fashion means of control. Welcome!

If you have other questions in this area, sing out

'BION'? Uh... what's that mean? 

Right off the top of my head, I DON"T see how you can have two DC power supplies, both of which are reversible, and one common wire. I'll sit down and think about it.

Thanks for the encouragement. Old ways aren't necessarily the worst ways to go. Just look at the diesel/steam controversy still simmering in back corners.

Thanks for the input.

Les


BION = Believe It Or Not

"Right off the top of my head, I DON"T see how you can have two DC power supplies, both of which are reversible, and one common wire. I'll sit down and think about it."

Yes, this does work and you will have to just take it on faith. (Doesn't matter how much you think about it and I recognize that it doesn't seem logical.) Once you actually wire it this way, you will see that it does work and as I said, the two power supplies can be set to opposite directions, and all of the electrons will find their way back to their proper homes. You can run as many different supplies, both ac and dc, as you wish on the common rail and all will coexist happily. Trust me on this one. 

But, the two power supplies must be separate. If you use a separate power source from the throttle (e.g., AristoCraft Ultima and AristoCraft Train Engineer) you need a seperate Ultima/TE for each of the two power sources. You cannot run two TEs off the same Ultima. If you run fully contained power supplies (i.e., the power supply and throttle in one box), you need two of these.


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## Bob Pero (Jan 13, 2008)

My railroad (Live Oak & Northern was designed and wired in blocks. I did this so that I could switch the yard and industries, and also cross over to get to the engine terminal from either main line. I used an old ATLAS HO wiring book as my guide. All my blocks are in a plastic sprinkler control cabinet with a track diagram on the lid. Each individual siding off the main line is controlled by a switch located in a weatherproof box for the siding next to the turn out that it controls. When not running operations with a dispatcher, all switches are set so that each loop is handled by it own controller. I use TE's and manual ground throws.


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## Pete Thornton (Jan 2, 2008)

gap both rails, it makes some of the wiring simpler.

Les, 

Please note (from bitter experience) that the advantage of separate blocks is not simpler wiring, it's simpler diagnostics when something goes wrong. (And it will - just wait and see.) If all blocks are separately wired, then you can still run trains while figuring out what is wrong with the bad block. Even though I planned to use DCC, my last indoor layout had separately wired blocks, for diagnostic purposes.


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## Les (Feb 11, 2008)

Bob,

That is very nearly what I intend. I will have a terminal (built first). Then a quartz mine, and a logging site. Anything else I can squeeze into a 22 x12' space will be gravy. The only commonality between the terminal module and either of the other two will be the ML. And I want to dual-gauge that for the sawmill. (Just for the heck of it). Thus, I'll be operating only one site at a time, one train at a time (I'm not into excitement anymore).

The more in detail I think of it, the more I believe I'll use a 'hot block' indicator, a ball signal. My era is ca 1875 backwoods, I like ball signals (operating) and there it is.

That'll give me both-tracks-gapped, independently powered 'sites'. Easy to build, maintain and troubleshoot, as Pete mentioned.

Thanks for all who inputted! Another decision in the bag.

Les

I should add all my turnouts will be manual stub-type.


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## Les (Feb 11, 2008)

Pete,

Right on. Easy diagnostics.

Les


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## Les (Feb 11, 2008)

Todd,

I'll take your word on it. See my post below to Bob. Thanks for your input.

Les


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## toddalin (Jan 4, 2008)

The common rail makes things so much simpler, less confusing, and cheaper. 

You not only save about half the wiring (and I mean ALL wiring including accessories, turnouts, building lights, etc.), but you save half the cost of rail insulators (@~$1/each).

If you assign the common rail as negative for your buildings and accessories, you only need to run the + wire (and pick the negative up off the track). Therefore, you NEVER have the delimma of having reversed polarity or wiring something backwards because you've set a standard. You always know that the wire to the track is negative.

People have problems with a common rail typically because they don't solder jumpers on their tracks, and/or they don't have enough "feeds" to the common rail for the lengths of track they are dealing with. (All of my rails have soldered jumpers and I have 6 feeds going to various areas for ~600 feet of track.) Without rail jumpers, you can loose your common connection through a track joiner or get a high resistance connection. Obviously anything or any train "downwind" from this high resistance or open point will suffer. Of course this can also happen if you run two wires to each block somewhere within that block, but the next block is unaffected by this. 

Don't let them scare you off. This is the cheap and easy way to do it and it works well. With just two power packs, how much diagnostics do you really think you will be doing? I've not had a single problem in 11 years of operating this way.


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## Les (Feb 11, 2008)

'Isolated blocks' was my first inclination, until I read the common rail article. After thinking about it, I'm going to stay with it because A) I understand it, B) rail joiner costs are a non-issue because my track will be handlaid wood w. strap-iron (acutally flattened 12 ga copper wire), C) I hope to do NO diagnostics, and D) 'they' didn't scare me off, they helped me think the issue through to a satisfying conclusion.

I thank all of you who've taken time to post your thoughts, perspectives and opinions.

Les


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## Guest (Nov 6, 2008)

Right off the top of my head, I DON"T see how you can have two DC power supplies, both of which are reversible, and one common wire.

think of electricity as closed circles. 
current goes from feeder to user, and comes back to feeder. 
only with a closed circle does the user work. 
but it is possible, that part of the circle forms part of other circles too. - the common wire. 
and, the electricity is sent like a kind of signal. and recieved again by the feeder as a corresponding signal. 
that is, why the circles don't get mixed up. 
so if one circle sends the electrons clockwise, the other circle on the common wire can send them counterclockwise. 
in the extreme, one could even use a common wire for 110v AC and for 12v DC. 

in your case, as you described, working sectionwise, and having regulator for each block and wanting actual control instead of watching trains go round - i would forget about the saving some foot of wire by use of common wire. 

korm


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## noelw (Jan 2, 2008)

Hi Les... Lots have given good ans. I just helped a bud of mine wire up about 700 ft of track and a few blocks. It depends on like others have said are you going to use more that one transformer/throttle. If using only one Throttle, like one I just wired up, he is only using one Aristo TM with the second half of the layout we installed a 7.5 watt @ 2amps. wire wound pot to regulate that section.
When running two train.........This will slow the nbr 2. train down so it won't catch up the Nbr 1 train. 

We also put in a few blocks and run around sidings. By insulating one side of the rails in those blocks with a SP/DT Radio shack switch to hold back a train or go around it. 

On our layout we use Two Aristo's Train Master R.C's, Two Aristo 10 amps power supply's and one fixed throttle @ 15 amps for our Eng. set up area. 
The main tracks are set up with DP/ center off / DT Switches. This is so we can block with any TM/RC. with "A" or " B" throttle. 
Just remember not to tie both Power supply's together. This makes when jumping say " A" block to" B" block, it will have no reference point back to the sec. side of the power supply's A/C transformer.

Usually if one block is turned On in one direction and the other block that is jumped is On in another direction.. It will just stall or go back and forth. or may throw a breaker if throttles are wide open. 

We installed 10 amp. resettable breaker on the secondary side of the T M's so it will trip first and not blow the 10 amp fuse. Usually only blow a fuse if throttle is wide open and breaker doesn't have a chance to heat up. 
The resettable breaker saves any short to the TM's. and keeps relays from sticking. 
Sticking relays is another story.. after sending them in 3 or 4 time to be replaced...

So kind of sums it up on ours.... we use on all of our blocks.. DP/ center off /DT Radio Shack Sw. ( Blocking both side of the tracks.) and using two different power supply's and two TM's Remote controls. and one fixed Throttle that can be Switched ( In the Eng. area set up area.) from "A" or "B" Throttle/ to center off/ Fixed throttle. Works simple and lets us have three trains operating at one time or just set it up to run one train and just sit back and watch them run.. 

Reason we have our set up this way is we like to do some switching of rolling stock. Move Eng's. around for next train set up or change Eng's. and can be run and fun with more that one person. We also, installed Intercoms in three areas being we can't see each other to keep things going. This has been lots of fun and lots of things to do either by our self or others that swing by to run trains to.

Using this idea we don't see the train coming back to the same place for 4 to 5 mins. sometimes.
Hope you get a lot of information off of these post. All railroads don't have the same ideas of powering them up. So off of these ideas ... it goes back to how you like to run your R.R. 
Happy R.R..Noel


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## Les (Feb 11, 2008)

Thanks for the input Noel.

Yeah, my RR is a pretty conservative one. Or will be, when I get it up and running. Switching, transfer operations, that sort of stuff appeals to me. The electricity part is just a means to an end. Simple is best.

Les


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## Les (Feb 11, 2008)

Korm,

Okay, think I get it: basically, the train's motor completes the circuit, doesn't matter to it which way it's running. Good.

Thanks,

Les


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