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Reverse Loop Advice

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Reverse Loop Advice
Posted by jb7778 on Tuesday, November 10, 2015 5:43 PM

  Sorry for the hand drawing but looking for some input where to gap/insulate my track for the 2 reverse loops. Its approximately 40 inches between the turnouts connecting the front to back mainline. First thought was to isolate those 2 sections but curious what others recommend? Type of reversers? Any other advice? I will be using a NCE DCC sysytem and modern diesel locomotives, no more than 2-3 in tandem, PECO Electrofrog with PECO PL10 and 13 switches.

All feedback appreciated, Thanks in advance!

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Posted by richhotrain on Tuesday, November 10, 2015 7:39 PM

How many trains will be running on this layout at the same time?

Rich

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Posted by jb7778 on Tuesday, November 10, 2015 7:47 PM

2 maybe 3 at times...

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Posted by richhotrain on Tuesday, November 10, 2015 7:50 PM

Wow, possibly 3 trains.  From top to bottom, what is the overall length of the layout?

Rich

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Posted by jb7778 on Tuesday, November 10, 2015 8:01 PM

32' end to end bench work, 26" radius on the ends.. Alot bigger than my drawing portrays!  1-2 trains utilizing mainline and maybe a staging engine servicing yard.industries not shown (when kids are around).  Id bet more times than not just myself and one train. Good questions, I had not considered multiple train reprocussions.

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Posted by richhotrain on Tuesday, November 10, 2015 8:30 PM

OK, 32 feet adds credibility to that diagram.

To answer your first question, you could create two reverse loops, one at the top and one at the bottom.  Alternatively, you could create one reversing section by isolating just the left side of the layout.  

The main issue will be to control the entry and exit routes of multiple trains. You might have a better chance to do that with a single reversing section.

Rich 

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Posted by richhotrain on Tuesday, November 10, 2015 8:34 PM

The Digitrax AR-1 is a good auto-reverser with a mechanical relay, and it is a lot cheaper than an auto-reverser with a solid state relay like the PSX-AR.  While the PSX-AR is a very fine auto-reverser, I don't think you need that level of sophistication on your particular layout.

Rich

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Posted by jb7778 on Tuesday, November 10, 2015 8:51 PM

With 2 loops exactly where would I isolate? Between the turn outs on the crossovers or on the mainline before the turnouts?

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Posted by richhotrain on Tuesday, November 10, 2015 10:53 PM

In my version of your diagram, the point of reverse polarity in each loop is indicated by the red circles.  The first set of gaps in each loop must be placed at that point of reverse polarity.  The green circles are the locations of the other gaps to completely isolate the reverse loops.

Rich

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Posted by jb7778 on Wednesday, November 11, 2015 5:46 AM

Terrfic that helps tremendously!

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Posted by richhotrain on Wednesday, November 11, 2015 5:53 AM

As always, the key is to keep the length of the train shorter than the length of the reverse loop, so that the train is not simultaneously entering and exiting the loop.

Since you will be running more than one train, the other concern is that one train not enter the loop while the other train is exiting the loop.

If the loop is long enough, though, it would be OK for both trains to be fully inside the loop at the same time.

Rich

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Posted by floridaflyer on Wednesday, November 11, 2015 12:07 PM

Rich Would you consider putting the gaps at the point ends of the turnouts?

doug

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Posted by richhotrain on Wednesday, November 11, 2015 1:34 PM

floridaflyer

Rich Would you consider putting the gaps at the point ends of the turnouts?

doug

 

Yeah, that would be the most convenient spot, and it would maximize the length of the reverse loop.

Rich

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Posted by BroadwayLion on Wednesday, November 11, 2015 3:48 PM

Essentially, your layout looks something like this. 32 feet is a long layout, and has lots of possibilities. The "Hight Line" through Syrah is the Fly in your ointment, otherwise you would have two simple reversing loops.

Let us assume that the loops are your two terminals, and allow them to have perhaps two tracks and a siding at Vineyard Vale, and several tracks and sidings at Booze City.

The gaps are as shown and while of course there are many switches, only the numbered switches shown would need to be controlled by your CTC machine, and dispatcher. Local switches around Chardonnay, Riesling, Merlot, Syrah, and Burgundy can all be hand thrown. Any switches that you add at Vineyard City and at Booze City can be handled by local towers.

Assume that both loops are used in the counterclockwise direction. The CTC switches are power routing, that all trains through the loop cities will stop in the station, and that power is applied to the High Line and on the Water Level Route.

ROAR

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Posted by jb7778 on Wednesday, November 11, 2015 6:12 PM

Rich/Floridaflyer Can you elaborate on this? I understand your previous diagram and using a total of 12 insulators, do you mean to put insulators on all 4 point rails on each of the 4 crossover turnouts for a total 16?

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Posted by cuyama on Wednesday, November 11, 2015 7:12 PM

With layouts roughly approximating a dogbone with crossovers, sometimes it's simplest to gap so that there is only a single reversing section. This is a bit counter-intuitive, but it often works well with DCC and auto-reversers (so no toggles need be thrown). 

Here four gaps create a single reversing section. I believe this would work, but a lot depends on the relative distances, which are hard to judge from the sketch -- so it might not work at all in this case. Sometimes an advantage to this approach is that the reversing section is single track.

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Posted by dominic c on Wednesday, November 11, 2015 7:26 PM

jb7778
All feedback appreciated, Thanks in advance!

The layout is long enough, but I don't know if you mentioned the width. By looking at the drawing, the reverse loop may not hold an average size train for the whole train to be contained in the loop. And like someone mentioned before, the train can't be longer than the reverse loop.

Joe C

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Posted by floridaflyer on Wednesday, November 11, 2015 7:32 PM

No. I would move the gaps at the turnouts on the left side of the diagram to the point ends of the turnouts, and eliminate the gaps at the red circles. Number of gaps would be reduced to eight and  each end is isolated

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Posted by jb7778 on Wednesday, November 11, 2015 8:24 PM

First, thanks for all the replys! Im very much a beginer and appreciate the insight..  

Due to the orientation of my pic the single reverse option went right over my head when Rich mentioned it in first reply. Smile There will be 14' between the 2 turnouts on right side, longer than any trains I plan to run. After seeing Cuyamas diagram it makes sense and seems like the most user friendly route? 

I guess Im confused of the operational differnces in the single vs double option. My original plans did not include the crossovers for fear of complexity. But being able to run the train the opposite dire+ction through scenes has driven me to figure it out!

Well over a year of planning and preparing so excited to be laying track I just want to be sure to get this right! Hate the idea of tearing up new track over something so easily prevented.

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Posted by floridaflyer on Wednesday, November 11, 2015 9:01 PM

jb, see my edited post above.

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Posted by richhotrain on Wednesday, November 11, 2015 9:40 PM

Let me add a few comments.

Cuyama's diagram illustrates the single reversing section that I mentioned previously.  It could be done either on the left side or the right side. The disadvantage of the single reversing section is that it limits multiple train movements more than the dual reverse loop approach.

Florida Flyer makes a good point about placement of the gaps. It could be done with 8 instead of 12 gaps, but the wiring protocol is different and requires more initial care.

Also, the OP mentioned the use of Peco Electrofrogs which requires additional gaps on the inner rails beyond the frogs, not to deal with reverse polarity of the reverse loop but to deal with the flow of current over the hot frogs.

Rich

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Posted by richhotrain on Wednesday, November 11, 2015 9:53 PM

This is florida flyer's suggested gapping.  Works fine, just got to be a little more careful with keeping the rail polarities matched. The upper and lower loops are reverse loops.

Rich

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Posted by floridaflyer on Thursday, November 12, 2015 9:31 AM

After thinking about this for a while, I believe that the OP would be better off going with rich's original diagram, 12 gaps at the points indicated. It will work fine, other methods would work but while rich's plan has more gaps, the plan is a good one.

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Posted by richhotrain on Thursday, November 12, 2015 9:50 AM

I think that, operationally, there are some challenges when running two or more trains, despite the length of this proposed layout.  

Whether the choice is the 8 gap option or the 12 gap option, it does seem that creating two reverse loops, one at each end of the layout, provides the most flexibility, operationally as well as visually.  Part of the challenge is visualizing where the reversing sections (loops) begin and end on the layout and where the trains are relative to the entry and exit points of each reversing section.

Rich

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Posted by cuyama on Thursday, November 12, 2015 12:44 PM

Since the dogbone-inspired single reversing section is inherently single-track, it seems to me (just my opinion) that it would be less of an issue operationally in terms of there being only one train in it at a time. But that's just my preference.

Since we haven't seen the layout drawn to scale, it's hard for me to know for sure.

 

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Posted by richhotrain on Thursday, November 12, 2015 1:12 PM

cuyama, while I tend to agree with you about the dogbone-inspired single reversing section, I am constantly amazed at the passion exhibited by some in favor of the two separate reverse loops at the ends of the dogbone. A lot depends here upon the actual scale of the layout.

Rich

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Posted by floridaflyer on Thursday, November 12, 2015 6:38 PM

The only issue I see with the single reversing section, as diagramed, is the very short length of the reversing section when trains enter from the crossover track (enter the turnout from the tangent)

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Posted by jb7778 on Thursday, November 12, 2015 8:33 PM

Apologize for the goose chase! I tried sparing myself the embarrasment of how poor I am with the SCARM program... Here is a pic and Id be happy to share the actual file but beyond benchwork Ive not had the patience to figure the rest of the programs capabilities out. (HO Scale) Benchwork in 30" deep except at ends and middle extension. Middle extension is also a future peninsula expansion point.

Otherwise does this info help settle the best recommendation? Im not opposed to placing gaps for single and double loop options while you guys hammer out the best solution! LOL  Sorry, Ive not been in capacity to respond any sooner while you guys are solving my problems!

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