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A reversing loop with cross-over

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A reversing loop with cross-over
Posted by pathvet9 on Friday, March 16, 2012 2:36 PM

I am sending along a picture schematic of what I sent Tony of Tony's Trains after buying his PSX-AR.

As you can see, he has sketched in the placement of the reverse block. The red and black are my buss writes and correspond to the track feeds, so as can be seen, I have one spot at the lower left turnout where track polarity will change. If I am running a loco counter-clockwise, it will be OK until it hits that turnout, when the right and left wheels will experience a change in polarity.

Tony claims that with his diagram, that is not problem???? I am not real good at figuring these things out but it seems to me that I have a short waiting to happen?  Confused

If so, how would one wires the circuit? I just cannot get my head on this.   Ashamed

 

 

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Posted by Texas Zepher on Friday, March 16, 2012 2:46 PM

pathvet9
The red and black are my buss writes and correspond to the track feeds

Why would you run your bus wires in a reverse loop configuration?   The bus will have to be broken into a main line portion and a reversing unit portion.

I have one spot at the lower left turnout where track polarity will change. If I am running a loco counter-clockwise, it will be OK until it hits that turnout, when the right and left wheels will experience a change in polarity.

Simply gap both legs of that turnout.  The main bus feeds the point side and output from the reversing unit feeds the frog sides past the gaps.

 

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Posted by pathvet9 on Friday, March 16, 2012 4:31 PM

Texas Zephyr - that is what I did (those gaps) but Tony claims they are un-necessary. I do not plan to have the buss wires in the reverse portions but there are track feeds outside of portion that are wired to the busses as shown.

Do I need to move the reverse portion back to the level of the turnouts and then have no buss feeds on the "loop" sides of the turnouts?  Dunce

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Posted by richhotrain on Friday, March 16, 2012 5:18 PM

If your bus wires follow your track, here is the required setup.

Gap the rails where the circles are placed on the following diagram.

When a train enters the reverse section by crossing the gaps, the PSX-AR flips the polarity to prevent a short. 

The following diagram shows the resulting flipped polarities.

The reversing section should be longer than the longest train so as not to confuse the PSX-AR.

If a train continues on a straight route and does not follow a divergent route across the crossover, the polarities remain in phase, and the PSX-AR is not required to reverse polarities since no short will occur.

In other words, the only point of reverse polarity is where the divergent tracks of the two turnouts, forming the crossover, meet.

Rich

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Posted by pathvet9 on Friday, March 16, 2012 8:55 PM

Oh Rich - I love it!! Seems like the way to go. BUT now I am going to put in my true track plan with the buss leads as well as the track leads.

 

So would the schematic look about the same???   Thanks so much for replying.    Bow

 

 

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Posted by richhotrain on Friday, March 16, 2012 9:33 PM

Jake,

If those three tracks leading off the crossover are stub ended and not connected elsewhere on the layout, you are fine as long as they are above the gaps that I drew on the crossover.

If they are connected elsewhere on the layout, or if they might be in the future, you could add gaps to the rails at the end of the divergent track on each turnout.  In other words, you could could gap six additional rails.

Rich

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Posted by pathvet9 on Monday, March 19, 2012 10:28 AM

Rich - sorry to be so long in replying to your kind comments but I am now in Florida taking care of my Mom for a week.

I have been ruminating on this plan and now realize that you had changed the buss/track polarity at that lower left turnout, and so I understand how that would work.

But i am afraid that i simplified things WAYYYYY too much and now I have re-drawn my true track plan (except for the reverse crossover on the other loop to the left). The trackage is more complex than i lead you to believe and now I see more major problems.

First I am wondering if, given all the turnouts and yard on the top, if it would be possible to put the reversing circuit to the lower left turnout area? I am also wondering what happens if a second loco enters the loop at the same time?

The way I see it, feeds 1,5,7,6,8, &15 are on the main buss, while #2,3,4,14 are on the out side of the PSX-AR.

Then I am not sure about feeds #2,10,9,11,12, & 13. I think at least those yard tracks should be gapped, otherwise they will draw main buss power if that is how they are wired to the main buss as I have done them??

As you can tell, I am overmatched with this layout but know there must be a way to right it. All I know is that Tony's solution will cause me to blow out my Zephyr again.!! Don't need that.    Ick!

Help!  Bang Head

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Posted by richhotrain on Monday, March 19, 2012 11:07 AM

Jake,

I would ask two things of you so that we can help you.

First, post a drawing of your entire track plan because otherwise we risk wrongly advising you.

Second, don't post a drawing of your buss wires.  Rather, post a drawing of your track configuration.

It would also help to know if your turnouts have the frogs wired or insulated.  in other words, are the frogs live or dead.

Rich

 

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Posted by pathvet9 on Monday, March 19, 2012 7:01 PM

Rich - that is the track plan, only with the track polarity marked. Also, my turnouts are all insulated or gapped(either Atlas or hand-made Fast-Tracks #5).

I hope i have clarified enough, sorry to be so slow to the uptake. If you want me to trace the tracks again, please let me know.

Thanks again.

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Posted by richhotrain on Tuesday, March 20, 2012 8:01 AM

pathvet9

Rich - that is the track plan, only with the track polarity marked. Also, my turnouts are all insulated or gapped(either Atlas or hand-made Fast-Tracks #5).

I hope i have clarified enough, sorry to be so slow to the uptake. If you want me to trace the tracks again, please let me know.

Thanks again.

I still have a couple of concerns.

One concern is that set of bus wires that end abruptly and are marked with a #10 in your bus wire diagram.  Is that meant to represent a stub end track, such as a spur?

The other concern is your earlier statement that you have now "re-drawn my true track plan (except for the reverse crossover on the other loop to the left)".   I am not sure what you mean by the term "reverse crossover" and what you mean by "the other loop to the left".  Can you draw that part of your track configuration ?  That could be crucial to proper wiring.

Rich 

 

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Posted by pathvet9 on Tuesday, March 20, 2012 9:00 AM

Rich - thanks for hanging in with me. I have internet connection again, so I re-drew what my track looks like. I took off all track feeds and am just showing the track polarity as it is now wired, including gaps that I have made. Yes, The #10 is a spur for a switching lead. I have also given some crude dimensions to let you know how long the tracks will be. The loops are 4' each. So there it is as laid for now.

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Posted by superbe on Tuesday, March 20, 2012 9:07 AM

To me your drawing is confusing.

As an interested observer I'd suggest you relabel your drawing by discarding the numbering of feeds and clearly show and number the turnouts.

The first thing that has to be done is to indentify any reversing loop.

Bob

 

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Posted by AlienKing on Tuesday, March 20, 2012 10:24 AM

I would gap the following 4 places and make the blue section the reversing section.

Depending on how long the bottom crossover is, you may need to move the gap that is below the crossover further into the loop. It may even make sense to move it all the way to just beyond the other turnout on the crossover.

 

 

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Posted by pathvet9 on Tuesday, March 20, 2012 4:15 PM

Thank you Allen - as usual, I forgot one other detail,I have 2 reversers to use so I will make 2 such separate loops. Now I just need to know how to wire the drops from the busses to keep the polarity so I don't blow up another Zephyr!   Oops

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Posted by pathvet9 on Tuesday, March 20, 2012 4:17 PM

Bob - hope you saw the revised plan that I posted with yellow and black tracks? Thanks for the input.

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Posted by richhotrain on Wednesday, March 21, 2012 5:14 AM

pathvet9

As usual, I forgot one other detail.  I have 2 reversers to use so I will make 2 such separate loops. Now I just need to know how to wire the drops from the busses to keep the polarity so I don't blow up another Zephyr!  

Jake,

You can have one set of bus wires with two auto-reversers.  The key is to correctly gap the rails to isolate each reversing section.

The only feeder wires that should be connected to the input side of each auto-reverser are feeder wires from the bus wires outside of any reversing section.

The only feeder wires that should be connected to the output side of each auto-reverser are feeder wires to the rails inside the reversing section controlled by that auto-reverser.

No feeder wires within any reversing section should connected to the bus wires.

Rich

 

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Posted by pathvet9 on Wednesday, March 21, 2012 7:58 AM

Rich - thanks for all the support. I do understand what you are saying and it makes sense. I had an epiphany Huh? last night as I was trying to get to sleep  Sleep

I can do what Tony originally said if i keep the buss feeds to the non-reversed tracks in the same polarity throughout the layout. Instead of having the polarity follow the curves, I am going to treat it like I started before, and thus leave all red to the inner track and black to the outer, then i only have to figure where to put my reversing sections within the curves.  WOW, how one it has taken for me to figure that!  Bang Head

One final question - what happens if a second train enters the reversing section while a first train is still in it? Maybe that is why one should keep the reverse section as small as a train length (or is it a locomotive length??)

 

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Posted by pathvet9 on Wednesday, March 21, 2012 8:56 AM

Here is the FINAL diagram, and thanks to my grandkids for the markers.  Yes

Let me know if anyone sees anything wrong with this iteration.   Bow

 

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Posted by pathvet9 on Wednesday, March 21, 2012 8:59 AM

Well, I see I forgot the black wire for the left lower crossover and also to say that the gaps would be put where the green wires start.

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Posted by rrinker on Wednesday, March 21, 2012 9:05 AM

 Are those reverse sections long enough to contain your longest train?

                  --Randy


Modeling the Reading Railroad in the 1950's

 

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Posted by floridaflyer on Wednesday, March 21, 2012 9:20 AM

 After looking at your diagram a bit longer, I still see the short when you use the crossover. You switched the colors of the track coming out of the upper green section but that is not what happens, reverser switches the track in the green section not in the red and black section. the crossover still has to be isolated. same is true of the lower crossover, you changed the colors of the red and green coming out of the reverser but again that doesn't happen . Look again at Alienking's diagram. It will work. At any rate the crossovers must be isolated and king's diagram shows that. His suggestion to move the lower gap is a good one and if you want to use two reversers, which in my opinion is good, you would have to gap the blue track from the lower crossover to the left hand turnout that starts the upper crossover. this would make each reversing section independent from each other

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Posted by pathvet9 on Wednesday, March 21, 2012 2:02 PM

Randy - I think they will be as they will probably end up as 2-3 feet each in length. But why does it have to be an entire train and not just the loco?

Cheers, Jake ---------------------------------------- Patience when resources are limited
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Posted by pathvet9 on Wednesday, March 21, 2012 2:09 PM

Floridaflyer - thanks so much for taking the time to scrutinize my plan. I do not quite see what you mean about a short in the crossover. Can you diagram where it will be?

It seems to me that if i run a train from lower left either through the crossover or around the loop that the reverser will change that polarity and then the reverser will correct it. Are you saying that it will not revert back coming out of the reversing section?    More headaches and sleepless nights for me! Ick!

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Posted by richhotrain on Wednesday, March 21, 2012 6:19 PM

Jake,

Nothing will happen if another train enters a reversing section while another train is already in the reversing section, at least nothing that will cause a short.  The problem is when one train is entering the reversing section while another train is exiting the reversing section because the auto-reverser will become confused regarding competing reverse polarities and won't know which way to flip them.

The locomotive will always trip the auto-reverser because it has metal pick up wheels.  If no other cars on your train have metal wheels, that is, all of the other cars have plastic wheels, then you will have no problem once the locomotive crosses into the reversing section.  However, if there are any trailing cars with metal wheels, that is sufficient to trip the auto-reverser.  In that case, the reversing section needs to be longer than the longest train entering the reversing section.  Otherwise, a portion of the train will be exiting while a portion of the train is still entering, thereby confusing the auto-reverser once again.

Now that ought to keep you up tonight !    Pleasant dreams !

Rich

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Posted by pathvet9 on Wednesday, March 21, 2012 7:40 PM

Rich - do you think my latest, last plan will work? Do you see a short as Floridaflyer does?

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Posted by pathvet9 on Wednesday, March 21, 2012 7:43 PM

Just as I had thought! 

Rich, do you see any problems with my latest, LAST train plan? Do you see a short as does Floridaflyer?  I THINK it works!!??   unless the train going out of the reverser picks up the wrong polarity but I think it should see the proper buss power?   

Thanks for the encouragement!    Bow

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Posted by rrinker on Wednesday, March 21, 2012 7:51 PM

 As long as you don't have any cars with metal wheels, or lights, the short reverse section will work. But i fyou have metal wheels, or lighted cars, or a lighted caboose, if one such car is existing while another is entering, there will be a short because the auto reverser will be in conflict.

                 --Randy

 


Modeling the Reading Railroad in the 1950's

 

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Posted by floridaflyer on Wednesday, March 21, 2012 9:24 PM

Upon further review I now believe it will work. The suggestion to make the reversing sections longer in a good one.

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Posted by richhotrain on Thursday, March 22, 2012 5:09 AM

pathvet9

Here is the FINAL diagram, and thanks to my grandkids for the markers.  Yes

Let me know if anyone sees anything wrong with this iteration.   Bow

http://i369.photobucket.com/albums/oo133/pathvet/DSC_0015.jpg

 

Jake,

This latest drawing makes no sense to me.

First, you are still drawing the bus wires, not the track configuration.  You are only asking for trouble if you are working under the layout with all of those color changes on the bus wires.  The bus wires should simply be strung in a continuous manner under the table.  The gaps in the rails on top of the layout and the routing of the feeder wires in and out of the auto-reversers provide the polarity changes, not the bus wires.

Second, as you have drawn the reversing sections, if I understand that diagram correctly with the green colors, those two areas by themselves are not reversing sections.  They are merely part of a section of track with the same polarity as the sections before and after.

Rich

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Posted by richhotrain on Thursday, March 22, 2012 6:22 AM

I sat down and drew the track plan that I think you are contemplating.

My first thought it that the track plan is fraught with problems even before considering the issue of reverse polarity.  As a single track configuration with mutiple trains, there is every possibility of a head on collision, depending upon the movement of the trains.

That said, there are two points where reverse polarity occurs.  One is the crossover on the lower left.  The other point where reverse polarity occurs is the left hand turnout below the programming track.

You could create one large reversing section to deal with both reverse polarity situations and only use one auto-reverser.  The second possibility is two adjacent reversing sections, each with its own auto-reverser. 

The main concerns are the length of the reversing section(s) and the length of the longest trains.

But again, I would be more concerned with the possibility of a head on collision.  This contemplated track configuration lends itself to single train operation.

Rich

Alton Junction

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