Help! Reverse Loop Questions


beiland

Well-Known Member



I posted this track plan in the opening dialogue as I felt multiple references back to it might be necessary. (sorry for the lousy quality, I don't do computer drawings)


Basics: This is the bottom deck of my 2-deck layout, I call the maindeck. The big round circle at the top is my external helix 'room'. I also have a flat mainline dogbone loop in there (shown), and it has a turnout on it (at point X) that feeds the peninsula, then continues on around to become the other half of the 2 mainlines on that left side (at point B).


Those 2 mainlines continue on around the room, cross the entrance-way bridge, then up a stone viaduct to go into the helix structure to make their way to the top deck.


On the left side of the room there is a long straight track running right along the wall. That track feeds the lower staging areas by way of a lower helix track.


Along the right side of the room, there is another long section of straight track along the wall that acts as a siding that eventually loops around to feed the peninsula area.


I've not included some details of trackwork in several areas as I did not feel they were necessary to this discussion of reversing loops.
 
I will start off these reverse loop questions with one of the most obvious examples. Looking at the upper left hand corner we see the mainline making a flat loop inside the helix structure, then returning as the opposite mainline at point B. I had figured that I would make the entry point somewhere along the other mainline at point A. That should be plenty long enough for my longest train.


One question arises. What do I do about the siding turnout at X point that feeds the peninsula? It feeds that double slip turnout that feeds the peninsula, and if I'm correct that double slip must be fed by 2 identical polarities??
 
I was next working on the siding on the right hand side of the room, and as I got up to the loop into the double slip I discovered this new problem,...I could end up with opposite polarities at point D & C,...at the double slip.

Compounding this situation is the freight yard ladder track, and coaling tower tracks that are connecting with the peninsula with the same polarities of those mainline tracks on the left side of the layout. I believe that all the tracks within my peninsula should be identical polarity??
 
The siding at X greatly complicates things. However, since it originates in a defined 'reversing section', it should either be reversed simultaneously, meaning it must be gapped at the distal end down the peninsula, or at the closest exit to that segment (a close turnout), or reverse everything it affords access to. Personally, I would reverse it at the same time and gap it at the southern turnout where it meets something else. Just hope you don't have two trains trying to cross gaps at the same time.
 
I was next working on the siding on the right hand side of the room, and as I got up to the loop into the double slip I discovered this new problem,...I could end up with opposite polarities at point D & C,...at the double slip.

Compounding this situation is the freight yard ladder track, and coaling tower tracks that are connecting with the peninsula with the same polarities of those mainline tracks on the left side of the layout. I believe that all the tracks within my peninsula should be identical polarity??
Simple here, and it agrees with my earlier suggestion of gapping that branch off the helix at the DS. Gap it there, reverse both the left side loop and its branch at the same time, and then keep the same phase/polarity for the right side track with its 180 deg loop, including the DS, and on down onto the peninsula.
 
Power Districts, how many?, how defined??

Reversing districts are now defined.

I'm debating with myself how to divide up my layout into power districts,..beyond the reverser districts.

At first I thought I would make the left had side (freight yard, steel, turntable) and the center peninsula all one district. Then make the right hand side another district, including the double tracks in the helix going up to the top deck (primarily the double tracks of the viaduct and the entire helix tracks).

I've now rethought that. Primarily my thought was to make the helix tracks their own power district, such that any problems in there would not shut down my trains from running individually on either the upper or lower decks. With that in mind, I redefined the lower deck districts. I took the center peninsula tracks away from being a part of the left side district, and made them a part of the right hand district.

1613623111099.png



Lower Deck: ?
So now I would have two power districts for the lower deck, and 3 reverse sections.

Helix:?
Its own power district

Upper Deck:?
1 reverse section (dogbone loop in helix housing), and at lease one big power district for remaining tracks. Or should I break this up into at least 2 power districts, left and right side of shed,....or maybe an individual one for the logging areas??
 
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I am reading this subject again (as I often have to do on electrical subjects), and I'll likely have some additional questions to try and determine how many PSX boards I need to purchase to divide my layout up into power districts.


So I came to this one,.....


Russ Bellinis
Sound makes it even worse. They recommend 5 amp breaker to keep you from having nusance shut downs due to too many locomotives on the system. The problem is that if one locomotive hits a switch thrown the wrong way, you can burn up the wiring in the loco before you hit 5 amps to shut down the system. If you have a lighted passenger train, it gets worse! All of those lighted cars add electrical load to the system. You need Frog Juicers to protect every switch. You can protect multiple switches with each Juicer, but every switch needs to be protected by Frog Juicers to flip the current if the switch is hit wrong to protect your locomotives. The 5 amps will protect the dcc system, but 5 amps is too high to protect locomotives from shorts.

I am using almost all peco insulafrog turnouts, so frog juicers are not possible. One of my major concerns is shorting out locos on turnouts I forgot to throw correctly. I was under the impression that the great PSX boards would take care of this problem, but reading the quote above gives me pause.
1) If I just have a single engine running in a certain power district is that more of a problem than if I had more engines drawing power in that district?
2) Is this any reason to make the power districts larger so we might be consuming more of that 5 amp load?




One more thing, if you have extra locomotives sitting on switch leads, the dcc board in the locomotive stays powered up even when the loco is parked, sound stays active. If you have too many locomotives on "ready tracks", you should have toggle switches to shut down the power on those tracks until you need to pull out a loco.

I have been made aware of this problem, and I am giving it due diligence in my staging areas and my turntable tracks.
 
Helix:
Its own power district
Upper Deck:
1 reverse section (dogbone loop in helix housing), and at least one big power district for the remaining tracks. Or should I break this up into at least 2 power districts, left and right side of shed,....or maybe an individual one for the logging areas??
railandsail.....Brian

Helix question again:
I'm wondering why I might consider the helix section its own power district when it will likely have no turnouts in it (so very little chance of shorting by trains/derailments), and it will likely have minimal number of locos in it at any one time??

Wonder if I should include the turnouts leading to the helix (both at the top and the bottom) in this 'helix zone/ district' ?
 
Double track, .....with double track entrance on bottom deck at stone arch viaduct,...single track entrance at top level.
 
Is there any reverse loops on the top deck? So when a train reaches the top level and lets say headed east can it head down the helix headed west. I say this because I do have a switch in my helix's neutral zone which enables the train to head east or west and continue on and then head back down the helix heading in a different direction because of the location of the switch being within the helix.. I was just wondering if you solved that problem in a different way?

George
 
I need to do an updated drawing of that upper deck.

Meantime let me see if I can explain it clearly The dbl helix tracks arrive at the upper deck on the left side of the room. They converge into a single track that runs around the perimeter of the room. The trains can continue to run around the room in that counterclock wise direction,...OR they can take a reversing loop of track accessed thru the back wall of the room (located over the top tracks of the helix). That loop sends the trains back in the opposite direction such that they arrive at the switch they found when they came up the helix. The trains can there make a choice as to which of the dble helix tracks they will take down.

So I know I need one PSX-AR up there for that reversing loop. Then the question is how many zones should i brake the other trackage up into?

Some moc-up plans here
https://model-railroad-hobbyist.com/node/36903?page=8

https://model-railroad-hobbyist.com/node/36903?page=10

https://model-railroad-hobbyist.com/node/36903?page=12

This is some of the industry down that left side of the layout room, on the very upper level
Cryogenic Plant, Helium Plant, and Refinery
https://model-railroad-hobbyist.com/node/37831
 
Laying Turntable Tracks

I want to get these tracks in position so I can drill all the holes thru the plywood deck to run their feeder wires (without excessive sawdust dropping on the staging tracks/turnouts below, and with more room to feed those wires up thru the holes).

Handy item for laying those tracks,...those 2 straight alum spacers...
image%28129%29.png


I've got a number of more tracks than I first anticipated ...oh well, all the more to display my steam engines !
image-20210302095023-1.jpeg


image%28130%29.png


Oops. that track feeding the turntable from the peninsula area has been a bear, and resulted in numerous re-alignments.
At first I was going to use a small radi wye Y Peco, and its radi was 24" which is what I wanted for the bigger radi to accept the larger steamers. BUT it created an S turn in that turntable feeder track, so I took it out and substituted a small radi conventional Peco that is also 24".

BUT it had a straight portion on its curved diverging track that had to be cut out. It was still not fitting in just right so I had to go back to those turnouts feeding it, and move them down a little. That resulted in a realignment of the double slip that fed the peninsula !! Everything is so inter-related when trying to get a real compact design,....a real challenge.
image-20210302100128-2.jpeg


And now I've discovered a way to get the small Peco in a little better aligned so it will feed a dead STRAIGHT track onto the turntable,...but of course I need to move one of those outdoor stowage tracks over just a bit,..so just un-glue it, and relay it. I do like that adhesive caulk someone on this forum recommended.

Now I'm trying to decide whether to wire this turntable/roundhouse scene into which of the 2 power districts I've decided to utilize on the lower level of this layout? I'm thinking I need to keep this zone separated from the zone that also includes my freight yard/diesel engine services/steel mill scene.
 
I've continued on with organizing these many tracks connected with the turntable and roundhouse area. Its a busy scene


I have a 3-way switch that takes the steam engines to the major coaling tower, then onward to a mainline. I've used a Roco 3-way that has broad radius diverging rails to handle those big steamers I have. It feeds 2 major coaling track, plus an auxilary track for the coal supply hoppers. Its a big Walthers coaling tower. I was also trying to maintain broad radius track here even while the coaling tower is quite close to the turntable. My minimum radius is like 24-25".
image%28133%29.png

(that's the coal drop shed sitting there on the track)


The 3-way is further down the tracks toward the turntable.
image%28134%29.png






I also have 2 radius tracks that bypass the turntable,...denoted her with arrows
image%28135%29.png

The lower one is a 22" radius curve that is meant for diesel engines and freight cars coming from the peninsula tracks (to the right of this photo), over to the freight yard and diesel services track (to the left of this photo). That 22" radi should handle most all the diesels that I have, including the 6 axles ones.


The other track is a 24" radius to handle the steam engines. Those steamers might well select the straight route of that turnout and go directly to the turntable,....or they might continue on the curved route and re-coal and re-water. It was kind of tricky getting all those curves, including the double curved Peco in there,...a challenge.


Maintaining that 24" minimum curve on the steam engine track resulted in moving down that group of switches on the peninsula area, and that forced me to change the position of the double slip up above them.At first I thought it was going to be something like a 4-5 inch change, but in the end I got it down only 1,5".
image%28136%29.png



image%28137%29.png






So now I need to start drilling my multiple holes for all the feeders wires, getting those feeders installed,....the I can put the staging deck back in its place below this area.
 
So over the past several days I got all those tracks surround the turntable and roundhouse firmed up and glued down in place. Then yesterday I began to drill all the holes for the DCC feeder wires for all of these tracks.


As I have mentioned before I was going to proceed clockwise around the perimeter of the turntable and wire all the various tracks with a polarity that matched the one particular end of the turntable bridge,.... such that anytime that end was mated to any particular storage track, their polarity would match.


I started at the track with the 3-way switch. That one would positive/negative rails matching the mainlines it was connected to.
image-20210308094949-1.jpeg






I proceeded all way around the circle to wire each track in the same manner/order. BUT when I got to the very last track (the other one that feeds the turntable from the peninsula area,...the very last one), I discovered a mismatch....
image-20210308095440-2.jpeg






That opened a new question,...what am I going to do about this? Either I have to remember this particular oddity,... or perhaps I might consider modifying the polarity of the entire peninsula area track group that this individual feeder track is connected to ?? I'm going to explore that possibility, as it had already been on my list to consider.
 
I want to explore the possibility of reversing the polarity of the peninsula tracks as a group,.. since I was already considering them a power zone with 2 reversing loop tracks contained within. Perhaps I can simplify this zone and make it compatible with my turntable??


Lets see if I can explain my thoughts with this new general view of my track plan (the lower main level)





Lets suppose I were to divide my plan up into 2 zones, 1) yellow one on the left to include the turntable/roundhouse, freight yard, steel mill,..... 2) green one on the right to include those tracks along the right hand side, AND the center peninsula tracks. Along either wall of the room I was wiring all the tracks such that the 'positive side' of the rail was closest to the wall.


I would have no problem with going around the perimeter of the layout WITHOUT any need to reverse polarity. I could go across the very top of the layout on the viaduct, and across the bottom at the entranceway bridge, ie I could cross between the 2 zones I pictured above without any need to change polarity.


If I took that siding on the very right wall into the peninsula area via the U curve up under the viaduct bridge (and coke plant), I would have no problem if all the peninsula tracks were wired accordingly with their polarity to match with that incoming track. From a topview observation it would appear the opposite polarity. Even the other connecting track from the peninsula down to the brick factory would be the correct polarity. This would mean I would NOT have to have 2 reversing track segments over on the right hand side of the room. They would all be polarity compatible.


Where I would run into a polarity problem would be where those 2 tracks meet each other between and just below the turntable area and the peninsula area,...(they are marked with a yellow line in the middle of the drawing),...that area where primarily steam and diesel engines alone are moving from the peninsula area to the turntable or freight yard ladder.





Is there some sort of 'brief manner' I could solve this polarity reversing problem in a local way in that area, OR do I need to make that whole right hand zone an electrical reversing loop??
 
...on another forum,....
do I need to make that whole right hand zone an electrical reversing loop??

Oh God no, don't do that. Way too many entrances and exits that multiple trains could be crossing at once and short out the whole system.

You can reverse something like an entire stub-end yard at once, but you have to physically limit the possibility of trains hitting both "sides" of the polarity at once.
 



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