Presently, my layout has one reversing turnback, three DPDT switches and five track feeders. I will be adding another reversing turnback. Considering all of the polarity changes, should I consider using the "common rail system"?
Presently, my layout has one turnback and a main line. I have plans for a 2nd turnback. I have the turnback wiring in a block with DPDT switch and the section of track leaving the turnback gapped to control by a 2nd DPDT switch. I do not want to use the throttle to control polarity when the train moves into the main line so I plan to add a 3rd DPDT switch. I assume that I should have terminal boards for both power in from throttle (+/-) and power to DPDT's, and from from DPDT's to track feeders?Regards,
I have figured out how to use the two DPDT switches to get through the 1st turn back but since I do not want to use the throttle diI hrectional switch, how do I add a 3RD dpdt for the main line feeders?
Living the dream.
Kevin,
Yes except that there are only two parallel tracks at the bottom of the page. Remove the third inside track at the botom of the page.
Dave
Ok, Mike, I'm tired of trying to understand what you write.
You need to be able to reverse the main and the reverse section separately. So you need two toggle switches wired in AFTER the power pack reversing switch.
I'm not interested in what the Atlas book says.
Sheldon out.
Really?
Why in the world would you want to be required to throw the two switches at the exact same time under a moving train?
That is no fun in having to do that, nor is it really a good idea, since there there will be no assurance of smooth transition.
In my 53 years at this, I have never heard or seen anyone suggest such a thing.
Separate switches, ignoring the switch on the power pack, is the correct way to handle this.
Sheldon
Dave K I plan to add a 3rd DPDT to contol the main line and not have to control direction from the power pack. Thanks all. Off to a local train meet/sale. Dave
I plan to add a 3rd DPDT to contol the main line and not have to control direction from the power pack. Thanks all. Off to a local train meet/sale.
Exactly as I proposed, that will allow smooth operation.
Well Mike, again I understand, but I'm not much for doing stuff over, so my instinct is to design the best comprehensive solution and do it once.
And I see ease of use as an important goal. My solution was by no means complex yet it might well be a complete and comprehensive solution for the op.
"Temporary" is just not in my vocabulary.
Mike, the two passing sidings serve no purpose if you cannot isolate a loco there. So my solution builds that into the system with less toggle switched to wire, and less toggle switches to understand and operate.
Another solution would be to eliminate the toggles for the sidings, and control them as X sections, only giving them power, always of the correct polarity, only when the turnouts are aligned to them.
But that still requires the operational convention of setting the two reverse switches based on "system direction" and using the power pack reverse switch to "back up".
LastspikemikeFinally, I understand reversing loops, polarity conflicts, common rail and double isolated blocks because I've wired them all incorrectly at one time or another. And in the space of less than a year of layout building. That qualifies me as an expert....
Some of the best learning comes through mistakes we've made.
My layout has many things I've done wrong, and each one will be fixed in the next layout.
York1 John
Lastspikemike I've thought about this a bit. The Atlas Twin switch illustrates an illusion about "reversing loops" and that is they aren't loops at all. If they are built as loops they are permanently shirt circuited. All that is required to accommodate separate blocks of track that need to be polarity matched is that the block section where the train is needs to be long enough to accommodate the whole train while the polarity is corrected (matched) in the adjoining block. It is not necessary for both blocks to be that long. The oval loop with connecting crossing tracks that reverse train direction are a special case of "reversing loop" that aren't loops. All that is required is to choose which section is "main" and which section is where the train is when the "main " has its polarity reversed. The trouble starts if you think the "main line" has to be the longer line or "the rest of the layout". That's why I suggest people stop thinking of reversing loops as a special problem. A reversing loop is just an isolated section of isolated block no different to any other. The fact that it loops back on itself is not relevant to the required wiring. As long as an entire train can be contained in that block while polarity is matched in an adjacent block it does not matter how long that adjacent block is. All that matters is that a reversing loop needs its own DPDT whereas a block not needing separate polarity control can use a SPDT for block control. If all your blocks used DPDT then reversing loops would present no issues. Finally, I understand reversing loops, polarity conflicts, common rail and double isolated blocks because I've wired them all incorrectly at one time or another. And in the space of less than a year of layout building. That qualifies me as an expert....
I've thought about this a bit. The Atlas Twin switch illustrates an illusion about "reversing loops" and that is they aren't loops at all. If they are built as loops they are permanently shirt circuited.
All that is required to accommodate separate blocks of track that need to be polarity matched is that the block section where the train is needs to be long enough to accommodate the whole train while the polarity is corrected (matched) in the adjoining block. It is not necessary for both blocks to be that long.
The oval loop with connecting crossing tracks that reverse train direction are a special case of "reversing loop" that aren't loops. All that is required is to choose which section is "main" and which section is where the train is when the "main " has its polarity reversed.
The trouble starts if you think the "main line" has to be the longer line or "the rest of the layout". That's why I suggest people stop thinking of reversing loops as a special problem. A reversing loop is just an isolated section of isolated block no different to any other. The fact that it loops back on itself is not relevant to the required wiring. As long as an entire train can be contained in that block while polarity is matched in an adjacent block it does not matter how long that adjacent block is. All that matters is that a reversing loop needs its own DPDT whereas a block not needing separate polarity control can use a SPDT for block control. If all your blocks used DPDT then reversing loops would present no issues.
Finally, I understand reversing loops, polarity conflicts, common rail and double isolated blocks because I've wired them all incorrectly at one time or another. And in the space of less than a year of layout building.
That qualifies me as an expert....
Mike,
Apparently most people don't think like you. Again, I understand what you are saying.
And that is largely the solution I layed out above.
BUT, it assumes a set of conditions not always in play. Call the loop the mainline, call it the loop, call it block #456, it does not matter.
I labeled things the way I did as part of making it easy to learn and understand, and to make the direction of movement of the trains correspond consistently to the position of the block toggles, a feature I found helps most people understand what they need to do.
Lastspikemike Well that's why I suggested making those short straights into the "reversing sections". Once the train is headed out of the crossing tracks making up the figure 8 you should be able to set the polarity correctly with one DPDT controlling all three straights together, Atlas wiring book figures 5-8 and 5-9 plus the text description in the chapter 5 explains how and why this would work.
Well that's why I suggested making those short straights into the "reversing sections". Once the train is headed out of the crossing tracks making up the figure 8 you should be able to set the polarity correctly with one DPDT controlling all three straights together,
Atlas wiring book figures 5-8 and 5-9 plus the text description in the chapter 5 explains how and why this would work.
If the whole train is not in a single block for reversing the polarity of the rest of the layout, there will be a short as soon as a metal wheel bridges a plastic rail joiner.
Now, with plastic trucks that might not happed with EVERY wheelset, every tme, but it is bound to happen at some point.
On my layout it would never work, I use mostly metal trucks with metal wheelsets, and all my cabooses are lighted for rear of train detection by the detection circuit.
So as soon as one axle is in one block and the other axle of that truck is in a block with opposite polarity - boom, short circuit.
Believe me Mike, I understand all your (and other peoples) reverse loop schemes. I would never use most of them in any case.
I still say, there is more fun to be had without the reverse loops.......
Because operation will be simple.......
No reverse loops on the 420' of double track mainline of the ATLANTIC CENTRAL.
I will turn trains on a dead end wye, no issues, very simple.
Lastspikemike ATLANTIC CENTRAL Still waiting for a track plan. Sheldon You can see the problems on the latest photos.
ATLANTIC CENTRAL Still waiting for a track plan. Sheldon
Still waiting for a track plan.
You can see the problems on the latest photos.
Sure can.
Biggest problem is that in todays world of metal wheelsets it is only going to work if the whole train is short enough to fit in the reverse cutoffs thru the middle.
Are we dealing with just one throttle/power pack?
I would:
Make the inner loop the mainline and make it one block.
Make each of the outer passing tracks blocks
Make each cutoff thru the middle a block.
Wire each block with a double pole, double throw, center off switch to control the polarity of each block separately.
Label the block toggles based on clockwise and counter clockwise.
Label the cutoff block toggles based on clockwise or counter clockwise entry/exit from the main.
Label the power pack direction switch forward and reverse such that forward and clockwise result in clockwise motion around the main.
Train enters cutoff, once train is in cutoff (it may need to stop simply based on length) mainline block is switched to counter clockwise. Sidings must match mainline for entry.
Off positions allow parking locos/other trains.
But if it was me, and I only had 4x8 to work with, I would ditch the reverse cutoff track completely and just add some sidings in the middle.
I appreciate the housekeeping comments but first I would like to operate my trains. Then, I intend to perform a cleanup.
Thanks,
Kevin is so right. Sloppy wiring is an invitation to problems.
My wring looks a lot like Kevins.
I wired the turnback loop DPDT switch as required. Did the same for the main loop switch. The main loop is fine but the turnback switch is shorting somewhere? I am getting a reading when the switch is in the middle and a short in one of the up positions. I tried to reveres wires in many combinations and chenger switches, all to no avail.