First, thanks everyone for the advice on laying track. Things are moving along and I have about 80% of the track down and have wired one loop of the layout and ran some trains, old tycos and athearns from 50 years ago that my father had and some new Bachmanns and Walthers that I recently purchased.
I want to start wiring the layout into blocks and some questions arose that I would like to share with you all for advice please.
I'll try to get to the point as succinctly as possible but if you need more information to offer guidance just let me know what you need and I'll post right back.
I ordered the Atlas 215 selectors for the blocks but I am now noticing that there is a connection for each switch for only one wire. Does that insinuate that I would wire the layout with common rail and each block would get the second wire from the selector? If that is so, what I can't visualize is how to dispurse the wire for the common rail from the powerpack to all the different blocks? I assume there is a device that takes one input from the power pack and then on the output side there are multiple termimals to send wires to the different blocks? Please forgive me if there are terminology gaffs. I feel like a 3rd grader trying to ask a question.
On another note I would welcome thoughts on gauge of wire to use. I scoured the forums looking for guidance and it seems for a DC layout 18 to 20 gauge is sufficient. I have Larry Pucketts's book on wiring and he suggests 12 to 14 gauge for DC but that seems like overkill. Or maybe not? My layout is about 18 feet long and about 4 feet wide on the ends and narrow in the middle - dog bone shaped.
Thanks! I would be happy to post my layout as grist for the mill if you are interested.
Hello All,
Thank you for the update on your progress.
Since you are using Atlas controllers I suggest purchasing The Complete Atlas Wiring Book.
This is a valuable addition to any model railroaders library- -whether using DC or DCC.
It not only describes the application of the Atlas components but also gives schematics for the more technically inclined.
Unfortunately, it is currently listed as Backorder on the Atlas website.
To answer your question about the Atlas block switches- -yes, they do use a common ground that is NOT gapped on the "negative" rail for DC use.
A single wire from the "negative" side(s) of the cab(s) can be daisy-chained from one cab to the next then to the track or distribution unit.
If you are concerned about voltage drop on the "negative" common rail you have a couple of options:
To energize the entire strip you can fabricate jumpers from spade connectors and short pieces of wire or buy jumpers made of solid metal to connect the terminals. From there it's a matter of running wires from the lugs (screw terminals) on the terminal strip to the track section.
Before converting my 4' X 8' pike to DCC I had 16 control blocks (4 atlas controllers) with only a single "negative" common.
Because of the size of my pike I found 20 AWG wire sufficient for the power feeds for both the common and blocks.
For the turnouts I used a separate power source connected to two Capacitive Discharge Units through Atlas switch control boxes (#56). But that's another post.
Keep the questions coming, update us on your progress, and...
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
My layout is 14’ x 10’ and the mainline is a twice around. I have 14 blocks on the mainline. I do not use common rail. Each block is a homerun to my control panel using #19 solid bell wire. Each block is controlled with a DPDT center off toggle switch. My longest block run is about 16 feet. #19 solid wire has 1.8 amp capacity, that's 1.8 amps to each block. Two locomotives draw less than 1.8 amps working together.I designed and built it before DCC. In 2006 I went with DCC but I added a relay to switch the track power from my DC power pack to my new DCC controller. I operate my layout dual mode, DC or DCC.I use EURO Terminal Strips for my block wiring and Busbars for power distribution.
Mel Modeling the early to mid 1950s SP in HO scale since 1951My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California Aging is not for wimps.
I have a DC layout as well. (Don't intend to go DCC. Too many engines = too much expense.) I have 24 power blocks on it. (Reverse G shape 24' x 12' approx Rail yard area) As already stated if you're only using one power pack Atlas Connectors (yellow switch) are good enough (8 of them on my layout). Another thing that I have done on my layout is with my remote turnouts. On my Atlas twin coils each turnout has its own set of outer wires (Yellow and blue for me) but the green (control) is daisy chained from the control panel to each of them. (Less wire use and works just fine.) But how you do it is completely up to you. It is your layout.
Like any wiring or control system, common rail has it's advantages and disadvantages. It's been around for decades, so if that isn't indication that it works fine I don't know what is. On a layout your size, it would be a good idea to fully insulate sections of it that can easily be disconnected from the remainder of the system should the need ever arise, but otherwise, carry on with your plan of using the Atlas selectors. They will work fine for you.
LastspikemikeWiring more than one 220 in parallel is interesting and the Atlas diagrams are not correct.
Mike
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. Like a train set oval. That's the drawback. Any fair sized layout benefits from using multiple feeders to each rail for reliability....
That may be so for block control to run more than one train at a time.
My common rail DC layout, not counting staging yards, industrial sidings and areas of double track, has roughly 300' of mainline, all of it powered through these two wires...
Power is from an MRC Controlmaster 20, running through a Stapleton PWM walkaround throttle. I've run over a dozen locos at a time, without issues or slowdowns. I use double throw/centre-off toggle switches to control the double-tracked areas and simple on/off toggles to control the individual tracks in staging yards and some industrial tracks. Couldn't be simpler.
Several hard-to-reach turnouts are are powered by wall warts (1 Tortoise, 4 Rapido motor drives, and 2 PFM/Fulgurex rack drives.
Wayne
LastspikemikeI found that the positive and negative input connectors are not as illustrated. The "inner" terminals are the same polarity and the outer terminals are the same polarity. Atlas implies the opposite in their diagrams. The polarity also doesn't run "straight through" as you might expect. Older 220 with four outputs as well as four inputs reveal this oddity. Later design do not carry the "ground" polarity across the unit, Atlas no doubt realized that wiring the ground to the last 220 in a chain was all that was required actually so deleted the ground connectors, which were the outer pair of terminals at the input and the inner pair at the output. Looking at the schematic wiring diagram for the 220 confirms what I discovered myself by trial and error, after a frustrating afternoon of my layout not working. I also discovered the faulty brand new 220 units in similar fashion, tracking the internal wiring faults using a multi meter and the schematic if what was supposed to be connected and disconnected by the various sliders. Clever design, poor manufacture. A major deficiency of all Atlas switch units is the center off slider switches. The red polarity reversing switches in particular are very poor quality. The blue turnout motor switches are a close second.
As for quality, I know people dog on Atlas's #56 switch controllers, but I've not had a failure with them personally, even using numerous ones for years, so I won't say they are poor quality. I've also used numerous 220 controllers, 215 selectors, 210 twins, and 205 connectors for years with zero failures. My only "complaint" is that the center point could have a little more resistance to help prevent moving past it. Maybe you've got a shady supplier that's selling you Atlas knock-offs?
Common rail works fine and it has worked fine since the beginning of model railroading. Personally I’ve always liked the ability to reverse direction in individual blocks and that requires both rails switched in a DC operation.All my layouts from 1951 to 2006 were DC only and I’ve always switched both rails. I also like the ability to just turn off the power to both rails to individual blocks.When I went DCC in 2006 I tried the DCC Guru way (buss wiring) and didn’t like it. The buss wiring screwed up my very nice signaling system so I went back to DC Block wiring for my DCC system. Every thing works great, DCC isn’t rocket science and the data rate at 8.5kb will work fine on even the worst wiring out there. All you need is the current carrying capacity to handle your load. An HO locomotive uses about 600ma to 700ma under full load, figure out how many locomotives you will operate in a single block and size your wire for that amount of current. In my case I never run more than two powered locomotives per train so I sized my wiring for a 2 amp max load per block. I went with #19AWG solid bell wire from my local Big Box store, twisted red and white low cost wire. I haven’t had any problems with my wiring for over 33 years.I operate my layout dual mode, DC or DCC, never both at the same time. To simplify the switching from DC to DCC and back I use a DPDT relay to switch the rail power between the two power supplies. I use the Accessory voltage from my DC power supply to operate the relay coil so that when I turn on the DC power supply the relay pulls in and switches the rail power from the DCC controller to the DC power supply, fail safe and no memory cells needed. I’m almost 84 and my memory cells aren’t what they used to be. Mel Modeling the early to mid 1950s SP in HO scale since 1951My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California Aging is not for wimps.
AblebakercharlieOn another note I would welcome thoughts on gauge of wire to use. I scoured the forums looking for guidance and it seems for a DC layout 18 to 20 gauge is sufficient. I have Larry Pucketts's book on wiring and he suggests 12 to 14 gauge for DC but that seems like overkill. Or maybe not?
I wouldn't think it should matter DC or DCC. Power attenuates over longer distance. So it depends on how long your bus is. There are tables you can google for DCC, for example, that would be also good for DC.
Tables I've looked at indicate that runs of less than 50' you can use 14 AWG wire for your bus. Longer than that and 12 AWG. I purchase rolls of 14 AWG house wire from Lowes for my bus and am sticking with that for size and bus length.
I am am running staging track feeders at around 8 feet so using 20 AGW bell wire for those from Lowes.
Rio Grande. The Action Road - Focus 1977-1983
AblebakercharlieOn another note I would welcome thoughts on gauge of wire to use. I scoured the forums looking for guidance and it seems for a DC layout 18 to 20 gauge is sufficient. I have Larry Pucketts's book on wiring and he suggests 12 to 14 gauge for DC but that seems like overkill.
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...
riogrande5761...I wouldn't think it should matter DC or DCC. Power attenuates over longer distance. So it depends on how long your bus is. There are tables you can google for DCC, for example, that would be also good for DC...
You're half right, if it will work for DCC it will work for DC, but the opposite is not necessarily true. Heavier gauge wiring is recommended for DCC for multiple reasons - the main ones being heavier loads (multiple trains running from single power supply) and detecting short circuits.
LastspikemikeI 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.
LastspikemikeDon'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.
LastspikemikeAdding 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."
LastspikemikeYou 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.
LastspikemikeMy 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.
LastspikemikeThings 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
LastspikemikeMuch 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.
greg - Philadelphia & Reading / Reading
LastspikemikeThings 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.
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
Alton Junction
CSX RobertThese 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
richhotrainIs there any way to sort this all out in order to salvage this thread?
what do you find confusing?
A lot of the replies seem contradictory to one another. As I said, somebody must be right and somebody must be wrong.
gregcnot 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.
CSX RobertI 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
richhotrainA 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.
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
richhotrain A lot of the replies seem contradictory to one another.
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.
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.
"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.
RichCommon 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/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
richhotrainBut 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.
LastspikemikeI 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."
LastspikemikeThe 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.
LastspikemikeThe 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
Lastspikemikeand 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
Lastspikemikeeach 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
LastspikemikeAtlas 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
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
Lastspikemike each Cab is given its own reversing switch and the powerpack reversing switches are not used.
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