# Reversing Loop diodes,insulators,& wiring details



## donut (Apr 5, 2008)

/DesktopModules/NTForums/themes/mls/emoticons/crying.gifI have a double slip switch that feeds into a Rt.turnout that completes the reversing loop need discussion on diodes location,size,insulating gaps locations.Wishing I could draw you all A schematic of track layout,but computer skills, no draw/DesktopModules/NTForums/themes/mls/emoticons/blush.gifLink to INFO.helpful,also rail schematics. This being my first post on MLS forums,I"ll say All aboard ! I see no wiring forum track power ? Searched archives found little except LGB Reversing Loop brass,I use stainless,must be another way to skin this cat. Regards,(donut @Q.com) >HELP/Phone Thxs.


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## toddalin (Jan 4, 2008)

Welcome to the forum. See the link for tips on setting up a reversing loop. 

http://www.trainweb.org/girr/tips/tips3/reversing_tips.html


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## donut (Apr 5, 2008)

Good thing I'm riding 1st class,quick reply. Looks like there might be A fee instore for electronics talented RR nut willing to fabricate circuitery,I can use to accomplish smooth ops.in auto control. Please to be in touch,Email in 1st post/DesktopModules/NTForums/themes/mls/emoticons/whistling.gif


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## Dougald (Jan 2, 2008)

*RE: Reversing Loop diodes,insulators,& wiring details*

For those folks who prefer traditional track power, I always recommend dropping by your local hobby store (or ordering from Kalmbach) to pick up a basic book on model railroad wiring. The scale makes little difference to the principlles - a reversing loop in HO is exactly the same schematically as a reversing loop in large scale, only the gauge of wire is different. 

Automated operation of a reversing loop is also possible but involves considerably more complex circuitry than a simple switch as some form of detection must be used to drive relays. Again, a basic wiring book will explain in detail. 

There is, in fact, a Track Power Forum if you look further down the listing of forums available. 

Regards ... Doug


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## toddalin (Jan 4, 2008)

Yes, considerably more complicated! 
It requires a magnet stuck on the bottom of the engine, an LGB reed switch, and an LGB EPL (dpdt switch) connected to the turnout motor. You also need about 14-20 volts a/c (usually the a/c tap on your power pack) to power the turnout motor and make it all work. 
Whew, this track powered stuff is complicated and expensive!!! /DesktopModules/NTForums/themes/mls/emoticons/tongue2.gif"


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## Dougald (Jan 2, 2008)

Track powered stuff for controlling multiple locos independently is complex and expensive, plus very labour intensive to install and maintain. 
And reed switches are not a very good way of determining polarity if bidirectional running with lots of backing and switching moves thrown in. Something more sophisticated is needed for both detection and direction. Think of a turntable as the simplest form of reversing loop. 
Now if you only want to run one train in continuous display mode ... it can be very simple ... but some of us enjoy seeing the train do more than go round in a circle. 
Regards ... Doug


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## San Juan (Jan 3, 2008)

I use a bridge rectifier for my reverse loop. But since we've changed to mostly battery power I kind of forget how it was wired. I bet someone here knows more about this type of setup though. 

I do know the loop could only be run in one direction and a flip of the direction switch on the power pack after the train passed the rectifier insulated gap was all I needed to do to change polarity. Spring switch is a must since it automatically routes the traffic the correct "one way only" direction.


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## donut (Apr 5, 2008)

THANKS again RR.chaps,I am wrapping my brain around this dilemma.with the help from another thread 
http://www.mylargescale.com/Communi...rumid/23/postid/13566/view/topic/Default.aspx 
I will post A rail schematic soon. 

Al McEvoy:key contributer/DesktopModules/NTForums/themes/mls/emoticons/wow.gif 
1st Class Member 

Brakeman 
Posts:27 

Send Message 
02/24/2008 8:19 AM Quote ReplyAlert 
You might contact this chap. Dave is quite the inventor with train electronics. If he doesn't already have exactly what you want, he'll build it. 
http://www.trainelectronics.com/ 


Al>>Looks like software coded chip W/infrared sensors,can make it auto run


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## donut (Apr 5, 2008)

*RE: Reversing Loop diodes,insulators,& wiring details*

http://www.trainelectronics.com/Reverse_Loop/Donut/ 

copy,& paste link to browser window address bar to see layout project Ops.diagram,& movements explaination. 

[email protected] To thank,Donut


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## donut (Apr 5, 2008)

Reverse Loop Controller 
with Double Slip Switch 
Revised 04-05-08

The objective of this project is to operate a train through an LGB double slip switch that, along with a standard turnout, can have the train navigate the reverse loop either in a clockwise or counterclockwise direction.

Overview: 
A reversing loop is frequently used by model railroaders to reverse an engine's path on a single main line. The problem with reversing loops crops up when track power is used as they create a short circuit within the track as the loop connects the two rails of the main line. This problem is addressed in a number of ways. The simplest and most common is to completely isolate a section of the reversing loop from the main line. This isolated section must be long enough to accommodate the engine and any cars that might have pickup wheels that feed power to the engine. The isolated section is powered from the main line through a bridge rectifier. This device supplies the same polarity of power regardless of the polarity that is fed into it.

When the train has fully entered the reversing loop a reed switch is tripped by a magnet under the engine triggering the controller which throws the DPDT relay reversing the power to the main line so that the train moves in the proper direction upon exiting the reversing loop. An optical sensor can be used in place of the reed relay and magnet with additional circuitry.

Layout: 
The layout is shown here. The crossover at the left presents no wiring problems and simply changes the train's direction after it completes the loop.

This detail shows the right hand section of the layout. There are a number of scenarios that must be accommodated:

Train on upper track moving from left to right - turnout set to go from "1" to "2" and slip switch set to "6" to "4" - the train enters the loop (clockwise) and exits on the lower track. Nothing needs to be done with polarity as no short circuits exit.

Train on upper track moving from left to right - turnout set to go from "1" to "2" and slip switch set to "6" to "3" - the train enters the loop (clockwise) and exits on the same track that it came in on. This is a classic reverse loop and a short circuit must be prevented by reversing the polarity at some point when the train is in the loop.

Train on upper track moving from left to right - turnout set to go from "1" to "3" and slip switch set to "3" to "6" - the train enters the loop (counterclockwise) and exits on the same track that it came in on. This is a classic reverse loop and a short circuit must be prevented by reversing the polarity at some point when the train is in the loop. Most turnouts will allow a train to go through the turnout from "2" to "1" without the switch being set that way so no automatic operation of the turnout (setting it from "2" to "1") is necessary.

Train on the lower track moving from left to right - slip switch set to "4" to "5" - the train enters the siding.

Train on the lower track moving from left to right - slip switch set to "4" to "6" -the train enters the loop (counterclockwise) and exits on the upper track. Nothing needs to be done with polarity as no short circuits exist. Most turnouts will allow a train to go through the turnout from "2" to "1" without the switch being set that way so no automatic operation of the turnout (setting it from "2" to "1") is necessary.

(images exceed max 640 pixel width, resized and reloaded, SteveC mod.)


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## Schlosser (Jan 2, 2008)

*RE: Reversing Loop diodes,insulators,& wiring details*

Donut, do you want automatic operation or is this a manual control operation? I just put down a temporary layout that has an similar configuration. 

If manual control, it's not complicated. You need two reversing switches and 6 (six) track insulators. 

Turnout 1 must have both rails insulated from track section 2. 

Turnout 1 must also have both rails insulated from track section 3. 

Track section 4 must have both rails insulated from the slip switch. 

The return loop starts at track section 2, goes around the loop, ending at track section 3, and includes the slip switch and track section 5. All this track will be controlled by one reversing switch. 

Turnout 1 and everything to the left of it and to the left of the slip switch, and that would include track 4, would be controlled a second reversing switch. 

Also please note: Your reference to a 'cross over' is incorrect; that is a crossing. A cross over is two switches that allow a train to cross from one track over to another track running along side of it. You will find a lot of cross overs in a station's 'throat' where trains often have many choices of routes to get to a specific track at the station. 

Now automatic running is a whole 'nother story. A full wave rectifier feeding the loop mandates one-way running around the loop which is a disaster when something goes wrong. You have but one reverse loop so once the train reverses, it goes that way forever. It has to back up around the reversing loop and a full wave rectifier prohibits that. A reversing operation is very difficult to automate. 

In 1947, I bought a book on wiring two rail track and used till it was memorized. Identifying a return loop in a maze of tracks can be quite difficult. 

Hope this might be of help. If you have a question about what I've written, just ask. 

Art


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## donut (Apr 5, 2008)

Posted By Schlosser on 04/07/2008 4:09 PM
Donut, do you want automatic operation or is this a manual control operation? 
Art 




Auto ops prefered,the siding off the slip switch,needs to be a funictional movement in auto ? Dallee Electronics, Inc. might have a product that can accomplish ?


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## toddalin (Jan 4, 2008)

This could probably be done using a combination of LGB EPLs, reed switches, diodes, and relays (maybe even latching relays) if creative thought is employed. 

Off-hand, I don't see the need for any rectifiers and trains could enter the loop from either direction using the right combination of reed switching points. But it would be a very time-consuming, mental excercise, to say the least. 

What does the winner get? /DesktopModules/NTForums/themes/mls/emoticons/tongue.gif


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## donut (Apr 5, 2008)

There fee,with in reason.


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## toddalin (Jan 4, 2008)

OK, I was giving this some thought and figured it out when I should have been sleeping. (I do my best thinking then.) This may even represent a whole new way of doing reverse loops too! 

This is both simpler /DesktopModules/NTForums/themes/mls/emoticons/tongue.gif and more complicated /DesktopModules/NTForums/themes/mls/emoticons/shocked.gif than originally envisioned but will allow for the trains to enter and proceed through the reverse loop from either direction. No rectifiers are employed, just some relays (I'm thinking three off hand) and three reed switches. Power routing to the spur would be accomplished using a simple LGB EPL on thta turnout. 

The caveat is that: 

"Train on the lower track moving from left to right - slip switch set to "4" to "6" -the train enters the loop (counterclockwise) and exits on the upper track. Nothing needs to be done with polarity as no short circuits exist. Most turnouts will allow a train to go through the turnout from "2" to "1" without the switch being set that way so no automatic operation of the turnout (setting it from "2" to "1") is necessary." 

Sorry, in this case, the turnout will need to be properly oriented for the through traffic for proper power routing. Can you live with that? 

As envisioned now, when the train goes through the loop, the wheels will push the points into their proper position (as you indicated). No automatic operation of the turnout needed, but can be added (but adds substantially to the complexity). 

But, I need to get so info on how you intend to run. 

1) Do you intend to use LGB turn-out motors? (I assuming yes.) 

2) Will you be using a common ground for your system? 

3) Will you fire your turnouts with dc or half wave ac? 

While this is fairly clear in my head, getting it onto paper is more complicated. /DesktopModules/NTForums/themes/mls/emoticons/blush.gif


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## Guest (Apr 14, 2008)

*RE: Reversing Loop diodes,insulators,& wiring details*

excuse me, gentlemen, 

but i don't see a reverse-loop on the pictures above. 
i see a 8-formed loop with a diagonal connection. 

i would think, the planning can't be based on normal reverse-loops, to be sucsessfull. 

i disagree with toddalin. there is a short-circuit in that plan. at the diagonal connection between the turnout and the slipswich.


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## Schlosser (Jan 2, 2008)

*RE: Reversing Loop diodes,insulators,& wiring details*

Maybe I'm missing something or just slow. For clockwise direction, the only decision that can be made is whether to reverse the train or not, and if so - that leads to whether to use the switch between track sections #1 & 2 or use the slip switch. 

After the decision to reverse travel to counter-clockwise direction had been made and executed, no further decisions can be made without stopping the train and reversing. Knowing where the end of a train is, can be very intimidating. Track occupancy detection, photo cells, nothing is easy. 

In computers, a program was capable of 'automating' a process or procedure but ONLY AFTER the process/procedure was carefully planned, thought out, and documented so that the program could be written. 

Automating a single track between two reversing loops is quite simple; magnets on loco, two track contacts, and two EPL switch drive motors. I don't see how a single reverse loop can, or needs to, be automated. 

Art


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## Guest (Apr 14, 2008)

if it were my layout, i would apply the KISS principle. 

i would change the places of the double switch and of the turnout. 

then i would have a loop, either as simple '8' or as double '8' 

all electronics needed would be the swich of the double-switch influencing the polarity of the right circle. 

like shown below:


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## toddalin (Jan 4, 2008)

Posted By kormsen on 04/14/2008 11:03 AM
excuse me, gentlemen, 
but i don't see a reverse-loop on the pictures above. 
i see a 8-formed loop with a diagonal connection. 
i would think, the planning can't be based on normal reverse-loops, to be sucsessfull. 
i disagree with toddalin. there is a short-circuit in that plan. at the diagonal connection between the turnout and the slipswich.




There is a reverse loop there, you're just not seeing it. /DesktopModules/NTForums/themes/mls/emoticons/blink.gif 

There won't be any short circuits when the insulators are installed and power properly routed.


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## toddalin (Jan 4, 2008)

Posted By Schlosser on 04/14/2008 11:22 AM 
Knowing where the end of a train is, can be very intimidating. Track occupancy detection, photo cells, nothing is easy. 
Art


A reed switch will determine occupancy. 

Posted By Schlosser on 04/14/2008 11:22 AM 
I don't see how a single reverse loop can, or needs to, be automated. 
Art


Need to learn to think "outside of the loop" (errr, box). /DesktopModules/NTForums/themes/mls/emoticons/satisfied.gif


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## Guest (Apr 14, 2008)

*RE: Reversing Loop diodes,insulators,& wiring details*

toddalin, 

that depends on the point of view. 

if i look, like i marked in '1', then i see a reverseloop too. 
but if i look at the whole run (2), i see an '8'-formed loop. (because the train does not come back to its 'reverse-loop')


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## toddalin (Jan 4, 2008)

Posted By kormsen on 04/14/2008 12:18 PM
toddalin, 
that depends on the point of view. 
if i look, like i marked in '1', then i see a reverseloop too. 
but if i look at the whole run (2), i see an '8'-formed loop. (because the train does not come back to its 'reverse-loop') 












You are exactly correct and as I noted, the first case does present a reverse loop that must be dealt with. My way takes care of this.


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## toddalin (Jan 4, 2008)

OK guys..., I've worked it all out and included a schematic. It uses five relays ($0.60 each), two N/O reed switches, one N/C reed switch, six track insulators, and a 6 volt power supply (or whatever voltage relays you decide on. Total cost is next to nothing. (Ahh the virtues of track power and a creative mind!) 
Reed switch 1 goes between the slip switch and the turn out. Reed switch 2 goes just to the right of the turn out and reed switch (N/C) goes about 3 feet to the left of the turn out. 
Use a dpdt toggle to flip your turnouts using one set of poles (and common ground). Use the other set of poles as the toggle switch shown. The insulators go on the sets of legs to the right of the turn out and to the left legs of the slip switch. 
Enjoy!


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## Guest (Apr 15, 2008)

*RE: Reversing Loop diodes,insulators,& wiring details*

i can not follow you, because i don't understand everything. 
these lettercombinations say nothing to me: 
N/O and N/C 

the only type of reed switches, i know, are those, like are used in the LGB contacts. 

please explain. 

thank you, 
korm 
.


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## toddalin (Jan 4, 2008)

Posted By kormsen on 04/14/2008 8:50 PM
i can not follow you, because i don't understand everything. 
these lettercombinations say nothing to me: 
N/O and N/C 

the only type of reed switches, i know, are those, like are used in the LGB contacts. 
please explain. 
thank you, 
korm 
.




N/O = Normally Open 

N/C = Normally Closed


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## donut (Apr 5, 2008)

1) Do you intend to use LGB turn-out motors? (I assuming yes.) correct, 
2) Will you be using a common ground for your system? Explain ? You mean polarity,yes 
3) Will you fire your turnouts with dc or half wave ac? I assume from power pack that would be what I get.half wave ac.


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## toddalin (Jan 4, 2008)

OK, now that I've developed the Lizard Bash Loop Control (see the Track Power Forum), we can get back to your situation. As I've demonstated (contrary to some peoples' thinking /DesktopModules/NTForums/themes/mls/emoticons/tongue.gif ), trains can travel through the loop in either direction, just so the loop and mainline are kept in sync. 

In your case, Reed Switch 2 would be placed along the loop between the turnout and the slip switch. You would also add rail insulators on the slip switch where it attaches to the main line. You would also place a reed switch (RS3) along the main line, just before the train enters the slip switch. This reed switch would be connected in parallel with Reed Switch 2. 

So, if the train leaves the loop it passes over RS3 and this "syncs" the loop to the main line so the train can enter the loop with correct polarity. Actually, when the train leaves in this direction, the loop and main line will be in sync, and tripping RS3 does nothing (except ensure that they are in sync). If the train then passes out of the loop through the slip switch and goes back to the loop the through the turn out, they are still in sync and the turnout is still properly aligned. 

If the train leaves the loop in a clockwise direction, when it passes over RS3 it resets the loop so that they are again in sync. If the train now passes out of the loop through the slip switch, the loop and the main line will still be in sync, but the turnout would be thrown against the train and it would enter the loop in the wrong direction popping a fuse. The cure for this is to also control the turn out using the Lizard Bash Loop Control (a modification to the circuit) to ensure that when the train reapproaches the loop it goes through in the proper direction..., or you can just toggle the turnout to reset things to the proper direction. 

Piece of cake! 

Soooooo...., what do I win?


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## donut (Apr 5, 2008)

Soooooo...., what do I win? " border=0>



Send PM., w/10-20 [email protected]


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