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Reality Check Needed - See File and/or Read Description

Rick Allison
 

I'm putting together my first layout in 40+ years-and I have a couple of wiring questions. I've read through Alan's website but have not found an example that matches my situation, so before I build it I thought it best to come here for a reality check.

The layout is a fairly simple 5x9 consisting of two concentric loops surrounding a figure 8. There is a Walthers/Shinohara "DCC-Friendly" double-crossover connecting the concentric loops at the 6 o'clock position, but wiring that should be pretty straightforward. Where it gets tricky is this:

There is also a double crossover between the inner loop and the left-hand lobe of the figure 8, at about the 11 o'clock position. The top of the right-hand lobe of the 8 is elevated over/above the inner loop, and there is a double-crossover between that right-hand lobe and the outer loop at about the 1 o'clock position.

Both of those double-crossovers each use a Walthers/Shinohara curved turnout plus three Atlas turnouts tied together with a 45-degree crossover. (See file HORRTG Layout Polarity Plan.jpg.)

My main question is: With insulating joiners separating the 45-degree crossovers from their respective inner and outer loops, can I use a single auto-reverser (like a Digitrax AR1) between my booster/bus and the figure 8, thereby reversing polarity on the entire figure 8 when an engine crosses over to or from either the inner or outer loops? Or do I need an auto-reverser near each of those double-crossovers? Or...?

Secondary question--although it's a small layout running 3 engines tops, is it worth setting up those two crossovers in such a way as to prevent two engines hitting the reversing figure 8 at more or less the same time (wiring the switches to ensure only one crossover can diverge at a time, or wiring the crossovers with a sensor so that if one is in use the other is de-powered, for example?).
 
Sorry for the lengthy description; hopefully I've got the ''HORRTG Layout Polarity Plan' file or Picture uploaded correctly to better explain what I'm trying to do...

Thanks in advance for your guidance,

- Rick

Flash Gordon
 

Rick,


We seem to be on the same "track", I am also returning to HO after decades away. 


We both have a 5 x 9 area. Mine was first created back in the 90's with my sons. When they left the layout went up in the barn rafters for about 15 years. After retiring I decided to redo it last year.'


See drawing in (Ed S stuff).  I do not have any reverses in my 5x9, but another drawing shows where I will be adding a little more track.  The new section will have a reverse loop, a wye and a double cross over between 2 main tracks. So I have reverses to deal with.


From reading an experimenting I have decided to reverse protect whole districts. 


I started layout in the program RTS 8.0 which shows wiring conflicts and resolved those. Now I am using XTrkCAd 4.03a so I can work on clearances.


Looking at your lay out I see the reverse loop in the middle. I would put a reverse protector to the left of switch 7 and protect that whole district. Then gap all the track leading into that district.


If your are using RTS 8 you can send me the file and I can try it out and I can send you mine if your are interested.


Ed S

Vollrath, Don <dvollrath@...>
 

Rick,

You have done well to draw out the track plan using different colors to identify rail polarity. Note that one must traverse both the A and B double crossovers in order to reverse the direction of a train. It looks easier to me to isolate the polarity reversing issue at crossover B.

 

1.       At crossover B Provide isolating joiners at both frog rails on both of the lower turnouts leading to the diamond. The upper turnouts and the diamond of B remain fixed at the polarity of the outer loop.

2.       Determine the maximum length of a train. Follow the inner loop tracks of the figure 8 from crossover B about that same distance in both directions from B. This is where you need to place additional isolating joiners or gaps on both rails for the minimum practical length of auto-reversing track.

3.       Going CW from B, I would put insulating joiners at the point end of the siding turnout at the 6 o’clock position of the loop. If that is not far enough from B, put them at the point end of the three-way turnout, keeping the lower turnout and siding as part of the isolated loop.

4.       Going CCW from B, I would place isolating gaps past the overpass, maybe near the 5 or 6 o’clock position of the left loop of the figure 8… or even at the turnout near the 10 o’clock position.

5.       That isolated track segment, including the two lower turnouts at B, form the polarity reversing section. Wire those tracks to the AR-1 auto-reverser.

6.       All other tracks on the layout including crossover C are constant polarity. Be sure to provide plenty of track droppers for adequate DCC connections.

 

You could interlock the double crossovers of A and B, but it is probably not worth the effort. That would also prevent the opportunity of a long continuous single train run overall of the mainline tracks in both directions.

For simplicity I recommend providing a single PB or toggle switch to select ‘straight’ or X-over for all 4 motor controlled turnouts at each of the double crossovers. Then there is no need to fiddle with multiple switches.  

 

If you plan on multiple operators. It might pay in the long run to further isolate the figure 8 loop into two pieces by adding insulating joiners at B on the straight track between the two lower turnouts. For now wire those tracks up to the single AR-1. But in the future you may want to add a 2nd AR-1 for independent multiple train operations at the industry tracks while another train uses the overpass. You may also want to isolate the yard under the overpass from the A crossover, and feed it via an electronic CB protected district.

 

DonV

 

From: WiringForDCC@... [mailto:WiringForDCC@...] On Behalf Of Rick Allison
Sent: Tuesday, February 04, 2014 9:43 PM
To: WiringForDCC@...
Subject: [WiringForDCC] Reality Check Needed - See File and/or Read Description

 




I'm putting together my first layout in 40+ years-and I have a couple of wiring questions. I've read through Alan's website but have not found an example that matches my situation, so before I build it I thought it best to come here for a reality check.

 

The layout is a fairly simple 5x9 consisting of two concentric loops surrounding a figure 8. There is a Walthers/Shinohara "DCC-Friendly" double-crossover connecting the concentric loops at the 6 o'clock position, but wiring that should be pretty straightforward. Where it gets tricky is this:

 

There is also a double crossover between the inner loop and the left-hand lobe of the figure 8, at about the 11 o'clock position. The top of the right-hand lobe of the 8 is elevated over/above the inner loop, and there is a double-crossover between that right-hand lobe and the outer loop at about the 1 o'clock position.

 

Both of those double-crossovers each use a Walthers/Shinohara curved turnout plus three Atlas turnouts tied together with a 45-degree crossover. (See file HORRTG Layout Polarity Plan.jpg.)

 

My main question is: With insulating joiners separating the 45-degree crossovers from their respective inner and outer loops, can I use a single auto-reverser (like a Digitrax AR1) between my booster/bus and the figure 8, thereby reversing polarity on the entire figure 8 when an engine crosses over to or from either the inner or outer loops? Or do I need an auto-reverser near each of those double-crossovers? Or...?

 

Secondary question--although it's a small layout running 3 engines tops, is it worth setting up those two crossovers in such a way as to prevent two engines hitting the reversing figure 8 at more or less the same time (wiring the switches to ensure only one crossover can diverge at a time, or wiring the crossovers with a sensor so that if one is in use the other is de-powered, for example?).

 

Sorry for the lengthy description; hopefully I've got the ''HORRTG Layout Polarity Plan' file or Picture uploaded correctly to better explain what I'm trying to do...

 

Thanks in advance for your guidance,

 

- Rick

 




Rick Allison
 

Ed,


Thank you so much for the reply. It's great that you are rescuing the old layout and incorporating in a (HUGE!) new one. Wish I had that kind of space. My old layout is long gone 


Thanks also for the guidance on placement of the reverse protector; I'll review that and Don V.'s recommendation as well before moving forward. It's exactly why I joined the group.


Alas, I am a cheap SOB and am using SCARM for my layout plans (no where near as versatile as RTS, but pretty easy to learn and 100% free in beta form) so that precludes an exchange of files; but I do appreciate the offer.


Once again, thanks for weighing in on the reversing district.



Rick Allison
 

Don,


Thanks, you're very kind about the drawing. 


All your recommendations make good sense, and isolating at max train length in either direction from crossover B should work well, as I'm not looking to run anything over 90" max. Leaving the crossover A and the upper portions of B at matching polarity with the loops they connect to will simplify the set-up and lessen the need to worry about two trains conflicting an auto-reverser. Excellent.


Yes, I'm planning to use plenty of drops, and single controls for each of the crossovers, but am glad to hear that advice reinforced.


I will give some thought to the multi-operator scenario, though at the moment it's just me and mine. As for isolating the section under the overpass: I was under the impression that a DCC engine operating in a district that experiences a polarity reversal will continue to follow directional cab commands independent of polarity--what then is the advantage of isolating that area?


I may produce an updated drawing based on your (and Ed's) guidance and put it up to have you confirm I've understood properly, and if so, it may be of future use to anyone else crazy enough to try a layout like mine.


Again, thank you for the explanations & input. VERY helpful.


-Rick



Vollrath, Don <dvollrath@...>
 

Rick,

You said “As for isolating the section under the overpass: I was under the impression that a DCC engine operating in a district that experiences a polarity reversal will continue to follow directional cab commands independent of polarity--what then is the advantage of isolating that area?”

You are totally correct in your understanding of train direction control with DCC. The only advantage of isolating a switching yard and powering it through a separate circuit breaker is that this is the area of the layout where operators tend to make mistakes and train cars are most likely to derail and cause short circuits. By isolating power to the tracks and switches in a yard with a separate circuit breaker (CB) district one operator can cause a track short circuit and power to trains on other parts of the layout being used by other operators or simply set up for continuous running will not be interrupted. This is a  hot issue on large club layouts. Some folks go overboard. There are arguments either way. But putting in insulated track joiners for sectionalized ‘block or district’ wiring is easy while you are first laying down the track. Cutting in track gaps and re-wiring is more difficult later, when you (may) decide to add CBs. Ditto for breaking the mainline into detection blocks for signaling.

 

DonV.

 

From: WiringForDCC@... [mailto:WiringForDCC@...] On Behalf Of allison.public@...
Sent: Wednesday, February 05, 2014 12:41 PM
To: WiringForDCC@...
Subject: RE: [WiringForDCC] Reality Check Needed - See File and/or Read Description

 




Don,

 

Thanks, you're very kind about the drawing. 

 

All your recommendations make good sense, and isolating at max train length in either direction from crossover B should work well, as I'm not looking to run anything over 90" max. Leaving the crossover A and the upper portions of B at matching polarity with the loops they connect to will simplify the set-up and lessen the need to worry about two trains conflicting an auto-reverser. Excellent.

 

Yes, I'm planning to use plenty of drops, and single controls for each of the crossovers, but am glad to hear that advice reinforced.

 

I will give some thought to the multi-operator scenario, though at the moment it's just me and mine. As for isolating the section under the overpass: I was under the impression that a DCC engine operating in a district that experiences a polarity reversal will continue to follow directional cab commands independent of polarity--what then is the advantage of isolating that area?

 

I may produce an updated drawing based on your (and Ed's) guidance and put it up to have you confirm I've understood properly, and if so, it may be of future use to anyone else crazy enough to try a layout like mine.

 

Again, thank you for the explanations & input. VERY helpful.

 

-Rick

 

 




Flash Gordon
 

To all:

We all know that if you have a reverse loop, it has to be longer then the length of a train with lighted cars.

I have a situation where a yard is part of a wye. This yard will have lighted passenger cars or a caboose with markers.

My thinking is to is to isolate the whole yard with the wye and use a revereing circuit breaker to control it.

Any thoughts?

Ed S

Vollrath, Don <dvollrath@...>
 

That is a perfectly good plan Ed. There is nothing wrong with having the entire yard part of an auto-reversing section. When is a high current condition sensed by the AR/CB, it will first try to reverse track polarity (the A-R part) then if the high current condition doesn't go away it will trip out on the overcurrent of a track short. (the CB part). All done in a split second. There may be other issues if your yard is double ended or has multiple entrances when there is more than one loco in motion at a time.

Note also that if your yard is single ended stub/storage tracks fed through a single switch on the wye the polarity can be controlled by the direction of the turnout leading into it. Use a relay or the DPDT switches inside a Tortoise. No need for an expensive auto-reverser.

DonV

-----Original Message-----
From: WiringForDCC@... [mailto:WiringForDCC@...] On Behalf Of Ed S
Sent: Thursday, February 06, 2014 11:50 AM
To: WiringForDCC@...
Subject: Re: [WiringForDCC] RE: Reality Check Needed - See File and/or Read Description

To all:

We all know that if you have a reverse loop, it has to be longer then the length of a train with lighted cars.

I have a situation where a yard is part of a wye. This yard will have lighted passenger cars or a caboose with markers.

My thinking is to is to isolate the whole yard with the wye and use a revereing circuit breaker to control it.

Any thoughts?

Ed S





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Flash Gordon
 

Don,

Thanks for the confirmation. The wye is the only two points out of the yard district and the yard ends. I put it in so I could turn engines around.

I needed a circuit breaker for the yard and found one that included a reverser.

Ed S

At 01:14 PM 2/6/2014, you wrote:


That is a perfectly good plan Ed. There is nothing wrong with having the entire yard part of an auto-reversing section. When is a high current condition sensed by the AR/CB, it will first try to reverse track polarity (the A-R part) then if the high current condition doesn't go away it will trip out on the overcurrent of a track short. (the CB part). All done in a split second. There may be other issues if your yard is double ended or has multiple entrances when there is more than one loco in motion at a time.

Note also that if your yard is single ended stub/storage tracks fed through a single switch on the wye the polarity can be controlled by the direction of the turnout leading into it. Use a relay or the DPDT switches inside a Tortoise. No need for an expensive auto-reverser.

DonV

Steve Haas
 

<<We all know that if you have a reverse loop, it has to be longer then the
length of a train with lighted cars.>>

<<I have a situation where a yard is part of a wye. This yard will have
lighted passenger cars or a caboose with markers.>>

<<My thinking is to is to isolate the whole yard with the wye and use a
reversing circuit breaker to control it.>>


Ed,

Don V. has given you a couple of good answers, they'll both work just fine.

There are, however, easier ways to handle this situation.

Your thoughts and Don's responses all center around reversing the yard on
that end of the wye.

Depending on how the other two legs of the wye connect with the rest of the
trackage, it may be easier to easier to use one of the other legs of the wye
for your reversing section.

Here's a simple example:

1) take a piece of paper and draw a large circle on it. At 11 o'clock and 1
o'clock, sketch in the two turnouts that split off the main and lead to the
yard you describe. Bring them down into the center of the layout, bring
them together at the third switch of the wye, and draw the yard below that.

2) Let's call the turnout at 11 o'clock turnout "A", the turnout at 1
0'clock "B", and the turnout that leads into the yard proper "C".

3) Cut double gaps between turnout "A" and "B" and "A" and "C", just to the
right of the frog of turnout "A".

4) Now move one train length counter clockwise from turnout "A" and place
another set of double gaps there. The length of track from this set of gaps
clockwise toward the two sets of gaps just beyond turnout "A" is your
reversing section. It's one train in length, and the resulting gaps are not
likely to be violated by another train.

Take the time to sketch it out - it works pretty good.


Best regards,


Steve Haas
Snoqualmie, WA

Flash Gordon
 

Steve,

Thanks for your reply. I understand how a conventional wye would work, but I am far from conventional.

Look in the photo section, if you list the albums by latest first my album should come up first. ( Ed S stuff).

Open the album and look at the "complete layout". At this point let me say my layout is geared to switching and making up trains. It will have two main tracks that will be kept clear while switching is taking place in the yards. DCC made this all possible.

At the bottom is the yard I am talking about. To the left is one leg of the wye and way over to the right is the other leg. You will see that there are two yards involved.

The left one is a passenger yard so I can back passenger cars into a station. The yard to the right is a freight yard for staging.

Neither leg is long enough for a lighted passenger train or a freight train with a lit caboose. Both legs need to lead into the yards so I can clear the main while cutting the cars.

My plan is to put gaps in the wye legs near the main line and consider all that yardage as one district, controlled by a circuit breaker / reverser. ( even a few tail light bulbs in critical areas). I am using an 8 amp booster for the whole layout with 4 amp circuit breakers for the large districts. Most of my engine are very old and some draw near one amp. So a lash-up or helper can draw two or three amps.

Once a train is in a yard, another train can enter the other yard so I could be working a passenger spotting and another person can be cutting freight cars.

I know it looks complicated but like I said I am not a conventional person.

Take a look and let me know if you see any errors in my logic. Next up is a triple cross over using two double slip switches and four turnouts that create another reverse.

Ed S

At 03:08 PM 2/6/2014, you wrote:



<<We all know that if you have a reverse loop, it has to be longer then the
length of a train with lighted cars.>>

<<I have a situation where a yard is part of a wye. This yard will have
lighted passenger cars or a caboose with markers.>>

<<My thinking is to is to isolate the whole yard with the wye and use a
reversing circuit breaker to control it.>>

Ed,

Don V. has given you a couple of good answers, they'll both work just fine.

There are, however, easier ways to handle this situation.

Your thoughts and Don's responses all center around reversing the yard on
that end of the wye.

Depending on how the other two legs of the wye connect with the rest of the
trackage, it may be easier to easier to use one of the other legs of the wye
for your reversing section.

Here's a simple example:

1) take a piece of paper and draw a large circle on it. At 11 o'clock and 1
o'clock, sketch in the two turnouts that split off the main and lead to the
yard you describe. Bring them down into the center of the layout, bring
them together at the third switch of the wye, and draw the yard below that.

2) Let's call the turnout at 11 o'clock turnout "A", the turnout at 1
0'clock "B", and the turnout that leads into the yard proper "C".

3) Cut double gaps between turnout "A" and "B" and "A" and "C", just to the
right of the frog of turnout "A".

4) Now move one train length counter clockwise from turnout "A" and place
another set of double gaps there. The length of track from this set of gaps
clockwise toward the two sets of gaps just beyond turnout "A" is your
reversing section. It's one train in length, and the resulting gaps are not
likely to be violated by another train.

Take the time to sketch it out - it works pretty good.

Best regards,

Steve Haas
Snoqualmie, WA

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