# Controls (e.g., reed switch & auto-turnout throwing) questions



## CliffyJ (Apr 29, 2009)

Hi,

Well, it's been two years, I'm still dealing with landscaping issues, and haven't laid a foot of track... but that day is a-comin', I can smell it! For now, in between humping rocks and shovelling dirt, I'm trying to work through a bunch of control issues (still). 

So here's a new one. I was planning (for now) to use track power, switch machines on all turnouts, with certain turnouts being auto-thrown via reed switches, for at least semi-auto train running between two reverse loops. But the more I think about it, the more complex this matter seems to be. For example:

- If turnout is manually overridden from a remote console, wouldn't the reed switches always be fighting that?
- Directionality of the loco seems critical: you have to use a diode, to make sure you throw the switch (and manage polarity), said diode being fed from rail power... 
- Similarly, one needs to offset both magnet and reed switch to one side of the track?
- What about backing a train through the fork? Can't have magnets on every car, right?

Sorry, I'm displaying my ignorance; but here's the main question:

Does anyone have a garden-railroad-applicable book or series of articles to recommend, which deal with these sorts of things? I've several books, but they don't seem to go deeply into these things.

Thanks in advance for your advice,

Cliffy


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## dbodnar (Jan 2, 2008)

Cliffy - I have written a number of articles over the years that deal with some of your questions. Have a look here:

Train Electronics - Articles Page[/b]

Specifically these articles are what you want to view:

*Automatic Block Switch Controller*
[*] Intro
[*] Automatic Switch Project - Part I - Block Control
[*] Automatic Switch Project - Part II - Turnouts
[*] Automatic Switch Project - Part III - Diode Speed Control
[*] Automatic Switch Project - Part IV - Sensors
[*] Automatic Switch Project - Part V - Controller
[/list] 
*Reverse Loops & Wyes*
[*] The Easy Way with Latching Relays!
[/list] 
*Sensors*
[*] Garden Railway Sensors Part I - Reed Switches & Relays
[*] Garden Railway Sensors Part 2 - Hall Effect Switches
[*] Pulsed IR Sensor Part 3 - 38 kHz Pulsed IR
[*] Infrared Train Detector
[/list] 
Please let me know if you have any questions.

dave
(There ya go Dave, the code has to be HTML v4.01/XHTML v1.0 compliant, SteveC mod.)[/i]


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 20 Oct 2010 04:23 PM 
Hi,

For example:

- If turnout is manually overridden from a remote console, wouldn't the reed switches always be fighting that?
- Directionality of the loco seems critical: you have to use a diode, to make sure you throw the switch (and manage polarity), said diode being fed from rail power... 
- Similarly, one needs to offset both magnet and reed switch to one side of the track?
- What about backing a train through the fork? Can't have magnets on every car, right?


Thanks in advance for your advice,

Cliffy


- No, both the manual console and reed switch throw the turnout momentarily and then it's done and no power flows to the turnout. The only time you would have such a conflict is if you toggle the manual control at the same time the train toggles the reed switch, and they were set for opposite directions.

Similarly, if you do a "leap frog" siding where a train comes in to a siding and toggles the turnout and power to a parallel track so the other leaves, via reed switch, and each of the parallel tracks has such a reed switch, toggling both simultaneously would be a no no as you would simultaneously send both + and - power to the turnout. (Sometimes the incoming train parks too close to the reed switch and this can and does happen, but there are ways around it.)

- You use a diode and a/c power to send to the switch. You do not use the power that goes to the rail for the engines so this is not an issue.

- The only reason to offset a magnet would be to have it control some function that you only wanted controlled going in one direction, like a whistle in a sound system. If you use reeds and magnets to control turnouts, they are usually in the center.

- That's when you use your manual override.


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## kormsen (Oct 27, 2009)

cliffy, 

most of your questions could be answered by the "lgb_00559_explore_the_world_of_lgb.pdf" - the section "Taking Control"
it can be downloaded from here: 
http://www.champex-linden.de/download_fremddokumente/lgb_00559_explore_the_world_of_lgb.pdf 

read that for understanding, how the system works. once understood, there are lots of ways to use auto control. 

basicly i use that system, i just built some of the components myself. 

to your questions: 

- If turnout is manually overridden from a remote console, wouldn't the reed switches always be fighting that? 

if "always" means continuously - no. the reeds just work for a moment. but if a train with a magnet passes over a reed, after you switched manually, the reed might switch it back. 


- Directionality of the loco seems critical: you have to use a diode, to make sure you throw the switch (and manage polarity), said diode being fed from rail power... 

not necessarily. i place the reeds so, that the reed, a train needs is the last one in a row, in the direction, the train moves. 
it might be better, to place the reeds in a way, that no train works its own switches, but a train on another part of the layout does it. 


- Similarly, one needs to offset both magnet and reed switch to one side of the track? 

i do use them just in the middle between the rails. 
(but i am planning, to try out if it would work to have different reeds on each side of the track and trains with magnets at different places. - if that is possible, there are lots of traffic possibilities!) 


- What about backing a train through the fork? Can't have magnets on every car, right? 

no need to. if you have one magnet per train and the reed far enough away from the fork, it works. 


happy planning!


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## kormsen (Oct 27, 2009)

Dave, a couple of you links seem not to work.


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## dbodnar (Jan 2, 2008)

Posted By kormsen on 20 Oct 2010 07:51 PM 
Dave, a couple of you links seem not to work. 
Right you are - I tried to edit them and, even though the HTML shows them to be correct, when I complete the edit and see them on the forum they don't work -

The only link that does work is the first one and that is the one that you need to use as it takes you to the page that has the others.

http://www.trainelectronics.com/articles.htm 

Sorry for the inconvenience but the editor seems to be a bit buggy.

dave


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## kormsen (Oct 27, 2009)

i was just studying the reverse loops and wye. 
i would love to incorporate a wye into my new layout. but i am afraid, it wouldn't work with the planned system.


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## toddalin (Jan 4, 2008)

Posted By kormsen on 20 Oct 2010 08:16 PM 
i was just studying the reverse loops and wye. 
i would love to incorporate a wye into my new layout. but i am afraid, it wouldn't work with the planned system. Wyes are extremely easy to do..., easier than reverse loops. I don't know what you are proposing, but I can't think of many situations where you couldn't get it to work. Maybe you could tell us what you are trying to accomplish?


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## kormsen (Oct 27, 2009)

that is what i do. (only with eight stations and eight trains this time)
half of the locos have the polarity changed.

if i would include a wye in the system, i would not only have to change polarity in the wye for the different trains, but on the whole layout the trains would need constant changing of polarity.

the only way could be, to make the layout one giant "reverseloop" that starts directly after the wye....


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## toddalin (Jan 4, 2008)

Posted By kormsen on 20 Oct 2010 09:15 PM 














if i would include a wye in the system, i would not only have to change polarity in the wye for the different trains, but on the whole layout the trains would need constant changing of polarity.

the only way could be, to make the layout one giant "reverseloop" that starts directly after the wye....



Show where you would include the wye.


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## kormsen (Oct 27, 2009)

thatis the point. i am not so sure. 

if i will try to do that, it will be for a harbor scene with two piers. 
i think, it should replace two stations. 
so i would have practically two wyes, crossing each other. on each pier one leg of both wyes. 

but that is a "no priority" idea only. - at the moment about 15' from about 420' are laid. and since my heart decided to run only in first gear i am a bit slow with these things.


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## toddalin (Jan 4, 2008)

Posted By kormsen on 21 Oct 2010 03:35 AM 
thatis the point. i am not so sure. 

if i will try to do that, it will be for a harbor scene with two piers. 
i think, it should replace two stations. 
so i would have practically two wyes, crossing each other. on each pier one leg of both wyes. 

but that is a "no priority" idea only. - at the moment about 15' from about 420' are laid. and since my heart decided to run only in first gear i am a bit slow with these things. 


OK, if I'm understanding your problem/concern, it's that once a train goes through the wye and is reversed, the other 7(?) trains would also be going backwards. Obviously, regardless of what system you use be it track power, battery, DCC, etc., you can't have one train going the opposite direction of the others, at least for long, until they collide.

So what you need is a parallel track to work with the wye so that you can reverse a train and store it in it's new direction until you get all of the trains reversed. Then you can put them back on the mainline. I can do this on my railroad. See my track plan.


Click above picture fo larger image


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## CliffyJ (Apr 29, 2009)

Thanks everyone for your input; just logged in, and will spend some time chewing on it all. 
(I'd forgotten to click the box to subscribe to the thread, but I've learned my lesson!)
Cliffy


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## CliffyJ (Apr 29, 2009)

Thanks Dave!

Ironically, it was your reverse loop relay circuits that I was basing my rail power schematic on. A couple days ago, I was flipping thru all my books, trying to find that circuit -- forgetting that it was from your site! So thanks so much, tremendous articles. And I've got a big fat shortcut on my desktop now.

One of the things I was forgetting was that the train needs to always go through the reverse loop on one direction. And if for non-automatic operation (e.g., there are sidings on the loop), I suppose one would disable that reed switch's input and operate the switch motor by other means. 

I'm sure I'll find what I need in your other articles. Thanks again!

Cliffy


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## CliffyJ (Apr 29, 2009)

Dave,

I've reviewed your articles, and they're great! I'm planning on using your relay-based circuit for track power. However, my concern is auto-throwing of the switch machine, via reed switches.

I'm assuming for now that the train has to enter the loop from one side of the switch. Which means that the switch must be thrown properly, to direct the train properly. 

The reed switch involved in track power reversal is within the loop. But how and when does the switch motor get thrown back to its 'default' position? Via the reed switch on the opposite loop?

If that's the case, I'll need something different, say, a timer, or a different reed switch downstream of the loop. This is because the loops are quite separated, with a bunch of things going on in between.

I'd kind of rather not have to have the loop entered from a particular leg. So to solve these things, and sense the direction of the train, I was conjecturing about offset-mounting of reed & magnet.

Sorry folks, I'm a slow learner some times.

Cliffy


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## dbodnar (Jan 2, 2008)

Cliffy - are you referring to the article on using latching relays to do reverse loops, wyes & such - 

http://www.trainelectronics.com/Reverse_loop_dual_coil_relay/index.htm

If so you will note a paragraph around the middle of the article that states:

*Note that neither of these layouts require powered turnouts. The switches are all spring loaded so that the train can enter when the points are going the wrong way without derailing. The spring allows the points to move but returns them to their initial setting once the train has passed. Most "G" scale switches, and many for other scales, work this way. As long as your engines and rolling stock are not extremely light in weight the switch points will be safely pushed aside as the train passes.*

I have used the design on both G scale & HO and it works well with both. It is also lots easier than including circuitry to throw the switches.

Please let me know if that answers your question or if I misinterpreted what you were asking.

thanks!

dave


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## toddalin (Jan 4, 2008)

This is my original concept for automatic loop control. If desired, the reed switches can be replaced with "double" track gaps (The Tortoise Bump A.S.S. concept) that will allow any engine or rail car with metal wheels to activate the system. 
Lizard Bash Loop Control 

The included diagram uses five relays to automatically control the polarity of both the loop and main line. While all relays are shown as 4pole double throw (4pdt), not all of the poles are used on every relay. Furthermore, Relay 4 is redundant to Relay 3, but is necessary for a fifth pole on that relay. If a 5pdt (or more) relay is obtained, Relay 3 may be replaced and the pole contacts on Relay 4 may be shifted to Relay 3 alleviating the need for Relay 4. 

As illustrated, the relays use 6 volts. But any voltage relays may be used, so long as the proper voltage is used to trigger them. The voltage connections that power the relay coils are shown in red while the current that goes to the tracks is in black. The Power Pack represents the power supply that actually runs the trains. The two Reed Switches are Normally Open (N/O). The Turn Out Toggle (TOT) represents the toggle switch that would be on the control panel used to activate an LGB turnout motor (or equivalent). We’ll use a double pole double throw (dpdt) switch that is off in the center position and spring loaded to return to the center. We’ll use one half of the switch (left blank in the diagram) to activate the turnout (assuming a common ground). The other half of the dpdt switch will activate the Lizard Bash Loop Control (LBLC). 

Follow along the diagram as you take a ride through the loop and see what happens. 

On our first trip, we’ll proceed from left to right (clockwise) going through the “straight section” of the turnout. 

Current flows from the power pack through Relay 1, Pole 3 and 4 (counting up from the bottom of the diagram) (R1P3 and R1P4) to the main line so the train has power. It then flows from the track (would actually be from R1P3 and R1P4 but this is more intuitive and serves for illustration purposes), through R3P3 and R3P4 to the loop so the train has power when it enters the loop. 

The operator toggles the turnout pushing the switch down. Voltage is applied to Relay 5 pulling down the armature. R5P1 is pulled down. Because no voltage is flowing to pole 1, nothing happens. (That’s OK at this point.) The train proceeds and first encounters Reed Switch 1 (RS1). The magnet closes the reed and voltage flows to R3P2. Because the circuit is open at this point, nothing happens and the reed switch is ignored. 

The train continues on and encounters RS2. The magnet closes the reed and voltage flows to R3P2. From there it continues on to R1P2, firing Relay 1. When Relay 1 fires, it reverses the current to the main line. But that then reverses the current to the loop and if left like this, the train would go backward before it reaches the main line again. (More on this in a moment.) When Relay 1 fires it also completes the circuit so that voltage flows through R1P1. This voltage continues on through R2P1, and back to the Relay 1 coil. This then makes Relay 1 stay “fired” (keeping the current to the main line reversed) even after the train clears the Reed Switch. 

As noted, when the current to the main line is reversed, it also reverses the current to the loop and the train would go backward when triggering RS2. As such, when the train passes over RS2 firing Relay 1, it also fires Relays 3 and 4 through R4P1. Relay 3 then reverses the current to the loop at the same time Relay 1 reverses the current to the main line. So the current to the loop is reversed and reversed again and stays as it was before the train passed over the reed switch. When Relay 3 fires it pulls R3P1 completing that circuit. Voltage flows thought R3P1, then though R5P1 keeping Relays 3 and 4 fired after the train clears the reed switch. 

At this point, the control of the turnout points can be accommodated though this circuitry (with some modification), can be controlled using the typical LGB circuitry (adding the appropriate reed switch to activate the turnout) but without the bother of polarity control), or the train can simply “push the points” into position as the train transitions out of the loop onto the main line and pulls away. 

So the train pulls away and takes care of business later to return to the loop. The turnout points are still where they were when the train left, either because they were fired by circuitry or because the wheels simply pushed them over. If left unattended, the train proceeds through the loop, this time in a counter clockwise direction through the curved leg of the turnout and first encounters RS2. Voltage flows though the reed switch to R3P2. But the relay is still in its active state and the voltage comes to an unconnected relay contact, and the Reed Switch is ignored. The train proceeds on and encounters RS1. Voltage flows again to R3P2 and this time passes through the relay on to R1P2. Relay 1 is also still energized, and the voltage passes through R1P2 and fires Relay 2. When Relay 2 fires, R2P1 opens interrupting the voltage that has been holding Relay 1 open and Relay 1 closes. This then reverses the current to the mainline. 

Again, the mainline feeds the loop and to keep the train from going backward before reaching the main line, the voltage from RS2 passes through R3P2 to R4P1 (that is still in a fired position along with Relay 3) to the coil on Relay 5. This fires Relay 5 that removes the voltage that holds Relays 3 and 4 open. Relays 3 and 4 then reverse simultaneous with the main line and the current from the main line and loop are again in sync. 

This will go on repeatedly with trains alternating clockwise/counterclockwise as infinitum without intervention. If the user decides to alter this natural rhythm, he can do so by toggling the turnout. This resets the relays to whatever “state” is selected through the Turn Out Toggle (TOT) also used to activate the turnout. When the TOT is pushed down it sends voltage to the Relay 5 coil pulling the armature that breaks the circuit through R5P1 holding Relays 3 and 4 open and they revert to the original clockwise direction relative to the main line. When the TOT is pushed up, it fires Relays 3 and 4 to the counterclockwise direction relative to the main line and they will latch in that position by sending voltage through R3P1 followed by R5P1. 

As noted, the reed switches can be replaced with simple track gaps allowing activation by any engine or railcar with metal wheels. The detectors consist of short sections of rail sandwiched between Aristo-Craft/LGB track insulators. The rail is only long enough to fit in the gap between the two insulators pressed together, so any power loss to a wheel is VERY short (less than half of a turn-out frog). The +6 volts shown in the schmatic is sent to the rail anywhere within the loop, and a wire connects the small rail section between the gaps to relay #3 as shown for the reed switch. So when an engine or metal wheel bridges the gap, it sends 6+ volts to the relay and the system activates. 

That’s it in a nutshell. Enjoy.


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## CliffyJ (Apr 29, 2009)

Dave,

I would prefer to do what you are describing. However, I'm planning on Train-Li WA-1 switche machines, and after conversing at length with Axel (who performed tests), the WA-1 won't tolerate that action, and must be thrown. Hence my prior query here, re. springing the switches. A gentleman mentioned that adding a spring in the throw bar mix will do the trick, but I've not had a reply on how to do that. Maybe it's a no-brainer?

Anyway, since Axel said so, I'd been assuming that the switch had to be triggered via reed switch, by a train coming into either leg. But now that I'm plotting where the reed switches go, more importantly, CAN'T go, I'm sorta jammed up. 

Some of the trains will consist of long strings of comparatively light ore cars. If I weight them all down, that would be a problem. 

So I quess I can't go with the sprung approach... or can I?

Thanks much,
Cliffy


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## CliffyJ (Apr 29, 2009)

Quite impressive!
I was hoping for something less complex though... but if this is the solution, it's the solution! 
How do you house your relays? And what relay manufacturer do you tend toward?
Cliffy


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 24 Oct 2010 04:34 PM 
Quite impressive!
I was hoping for something less complex though... but if this is the solution, it's the solution! 
How do you house your relays? And what relay manufacturer do you tend toward?
Cliffy


Thanks.

I would either put them in my control panel, or in a weatherproof box trackside.

This is_* A*_ solution and essentually does with simple relays what one of the LGB systems does using the EPLs with supplementary switches attached, or what Dave does using the latching relays.

But, this soultion lets you use any Internet surplus (= CHEAP) relays rather than expensive LGB components or expensive and hard to find latching relays. (You can buy all five relays and a wall wart for less than one LGB supplementary switch, let alone their reed switches and other stuff to make the system work.) Look at surplus electronic sites (such as allelectronics and Electronic Goldmine) to find a wealth of cheap relays, many of which would be suitable. Also find things like wall warts to power them at a few bucks.

The track gap method would allow you to run any engine or railcar with metal wheels through the system and activate it without the need for magnets (e.g., you could back a train through). That has several advantages to reed switches, but is not appropriate in every case (e.g., a leap frog) where a reed switch and magnet can more easily accomplish the task cheaper. It is actually a little cheaper to use surplus reed switches (~$0.75 per detector) as opposed top the LGB and AristoCraft track insulators (~$2.00 per detector) to do the track gap method.

If you can show us your intended track plan, we can come to a better understanding of how to best accomplish the task.


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## CliffyJ (Apr 29, 2009)

Thank you Todd (is it Todd?), I'm slowly getting your schematic.

Not quite there yet, but in a nutshell it seems to me that you are ignoring the "entry" reed switch, and honoring the "exit" reed switch -- regardless of train direction. I really like that. 

Any diagram I put up wouldn't really help the discussion at this level: yours is just fine for discussion purposes. 

I'm only trying to get my arms around these requirements:
- Track power
- Entry into a reverse loop: to either direction is preferred, but I'll live with uni-directional if I have to
- Reed switch(es) in the loop handle the reversal of main line polarity
- Same reed switch(es) or other one(s) MUST handle the physical throwing of the stinkin' switch -- unless someone can prove to me a reliable sprung throwbar method that deals with a string of lightweight ore cars
- AND, if the solution demands the train always enter the loop so that it ALWAYS goes to one leg or the other, the system must accommodate the physical throwing of the switch beforehand.
- I need to send a momentery signal to the switch machine, and it needs to be rock solid in position.


Now, the thing I like about Dave's circuit is that the loop is always rectified to be a certain polarity. On the other hand, that's the thing I don't like: always needing to enter the loop from a particular leg, with the train going a certain direction. I can live with that, but how to reset the switch (trigger the switch machine) properly? THAT's the beginning of my concerns.

Clearly, both you dudes are smarter than I am -- or at least more lucid, seeing that my RR/Internet time generally coincides with Miller Time...









Having confessed that, I'm wondering if there is a way to blend these concepts... say, rectify the input(s) to a single latching relay...?

I'll mess with it [I haven't had THAT much beer!! But don't expect much regardless...], but please let me know if either of you are seeing important things I've not.

Thanks for your hep!!

Cliffy


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## CliffyJ (Apr 29, 2009)

OK, I've been trying to work thru this, and here's my findings -- ripe for anyone to correct, but here goes. 

To me, this all seems to boil down to a "smart" directional sensor -- one that knows which direction the train is going. Such would throw the points and manage the main line polarity shortly prior to exiting the reverse loop. 

I've suggested offset magnets, but I guess from the response that such won't work (I'm the one with zero hands-on experience, so thanks for your patiance everybody). Makes sense though, after looking at LGB magnets: big momma's, unpredictable fields and results. So much for offsetting the magnet -- unless someone can help me out here, with solid evidence to the contrary. 

OK, centered reed switches. But is there a means to make them direction-sensitive? 

Here's one approach, and please permit me to be brief enough to seem like I know what I'm talking about, though I do not. 

Into reverse loop, on either leg, there are two wires coming off the rails. These two pairs are, say, 2' from the frog, on either leg. 

Let's deal with just one of those wire pairs. Both have diodes, bringing rail power to an SPST relay coil. The diodes only allow current to said coil, if rail power is "going" a certain "direction". 

Question 1: do loco's always have rail power coming from one rail or the other? I think so, it's embarrasing to ask, but someone please help me out here. 

Anyway, the diodes only allow the relay to fire (via reed switch) IF the train is going in a certain direction (assuming the above question is answered in the affirmative). 

Question 2: can relays be had with coils sensitive enough, and robust enough, to handle any level of track power? Say, 4v-24v? Probably not? On the other hand, aren't we talking about handling only signal power? 

Regardless, it seems like this form of approach might handle the momentary throwing of the switch motor, and latching-over of the power latching relay. 

Thanks very much, 

Cliffy 
Pol


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 25 Oct 2010 04:00 PM 
Thank you Todd (is it Todd?) 


in a nutshell it seems to me that you are ignoring the "entry" reed switch, and honoring the "exit" reed switch -- regardless of train direction. I really like that. 

- I need to send a momentery signal to the switch machine, and it needs to be rock solid in position.



Thanks for your hep!!

Cliffy



Yes, it's Todd

Thanks.

Can do that using the something like the TrainMaster maybe easiest and costliest), the LGB components, a little harder to wire, but reliable and less costly, or through more sophisticated electronic methods (cheapest using Internet surplus, but hardest because you will soldering your own using "custom designed" circuits to the application that sometimes require "troubleshooting."


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 25 Oct 2010 05:15 PM 
OK, I've been trying to work thru this, and here's my findings -- ripe for anyone to correct, but here goes. 

To me, this all seems to boil down to a "smart" directional sensor -- one that knows which direction the train is going. Such would throw the points and manage the main line polarity shortly prior to exiting the reverse loop. 

Here's one approach, and please permit me to be brief enough to seem like I know what I'm talking about, though I do not. 

Into reverse loop, on either leg, there are two wires coming off the rails. These two pairs are, say, 2' from the frog, on either leg. 

Let's deal with just one of those wire pairs. Both have diodes, bringing rail power to an SPST relay coil. The diodes only allow current to said coil, if rail power is "going" a certain "direction". 

Question 1: do loco's always have rail power coming from one rail or the other? I think so, it's embarrasing to ask, but someone please help me out here. 

Anyway, the diodes only allow the relay to fire (via reed switch) IF the train is going in a certain direction (assuming the above question is answered in the affirmative). 

Question 2: can relays be had with coils sensitive enough, and robust enough, to handle any level of track power? Say, 4v-24v? Probably not? On the other hand, aren't we talking about handling only signal power? 

Regardless, it seems like this form of approach might handle the momentary throwing of the switch motor, and latching-over of the power latching relay. 

Thanks very much, 

Cliffy 
Pol 






Sure you can do this and I do something similar for my Tortoise Bump Accident Sentintal System (Bump A.S.S.) that protects my "X" crossing.

But to run trains slow, you need to use 6 volt relays (or less) and this will allow operations down to about ~7 or less volts on the rails..., which is pretty slow.

No the relay will not be able to take the full range of voltages that you apply to the track. So you send the track power through the diode so it only triggers in one direction. Then you send it from there to the 5 or 6 volt regulator and use the appropriate relay.

Of course, the new Bachman trains have an internal switch that lets them run in either direction so would foul the system if set for the wrong polarity.

If you don't use "springy" turnouts, you still need ~16 volts present to throw the actual turnout motor.


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## CliffyJ (Apr 29, 2009)

Thanks for the further info Todd. 

I checked out Electronic Goldmine (http://www.goldmine-elec.com/) and you're right -- fantastic prices!
Still working thru your circuit. Had to put it in a Word doc to read it (got tired of the scroll bar!  ). Couple more questions if you don't mind.

I suppose that all the relays could be mounted on a breadboard, pre-wired as a group and put in a weatherproof box. 

Which brand of box do you use? For control panels I'm liking these (they're ~$30):
http://www.polycase.com/item/wa-35.html

Any advice on what product to use in regulating track power down to ~5 or 6 volts?

This is sort of off-topic, but in regards to pushbuttons I think these are nice:

http://www.cherrycorp.com/english/s...rproof.htm

They're waterproof, illuminated and only ~$5 at Digikey. Ever used 'em?

Cliffy


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## dbodnar (Jan 2, 2008)

Cliffy - Have you chosen switch motors to throw your switches? The reason that I ask is that some switch motors, LGB's in particular, continue to draw power after they have thrown. My measurements show that they draw about 0.5 amps at 12 volts. This is not likely to burn up the switch motor but I don't like a component being left on when it is not necessary.

The reason that I ask is that you could easily add another latching relay and two more reed switches to the reverse loop to throw the switch motors to the appropriate direction. The switch motors from Aristo and the Tourtoise draw little or no power after they have thrown. They would work quite nicely with the latching relay. LGB's switch motors would be much more likely to damage the contacts on the relay after an extended time.

Thanks

dave


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 26 Oct 2010 04:55 AM 
Thanks for the further info Todd. 

I checked out Electronic Goldmine (http://www.goldmine-elec.com/) and you're right -- fantastic prices!
Still working thru your circuit. Had to put it in a Word doc to read it (got tired of the scroll bar!  ). Couple more questions if you don't mind.

I suppose that all the relays could be mounted on a breadboard, pre-wired as a group and put in a weatherproof box. 

Which brand of box do you use? For control panels I'm liking these (they're ~$30):
http://www.polycase.com/item/wa-35.html

Any advice on what product to use in regulating track power down to ~5 or 6 volts?

This is sort of off-topic, but in regards to pushbuttons I think these are nice:

http://www.cherrycorp.com/english/s...rproof.htm

They're waterproof, illuminated and only ~$5 at Digikey. Ever used 'em?

Cliffy



For my "sub modules" I just buy waterproof plastic boxes at Home Depot, Lowes, etc., They come in 4"x2", 4"x4", 8"x8", etc. I typically use the 4"x4" place a birdhouse over them.

The surplus houses will also have 5 and 6 volt regulators very cheaply. Get them where you get your relays.

I would not use push buttons, but a toggle switch. When you throw a toggle a certain way, you know the turnout throws that direction. With a pushbutton (unless you use two), you don't know which direction you are throwing the turnout when you push the button. Besides, surplus toggles are lots cheaper than that.


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## toddalin (Jan 4, 2008)

Posted By dbodnar on 26 Oct 2010 07:21 AM 
Cliffy - Have you chosen switch motors to throw your switches? The reason that I ask is that some switch motors, LGB's in particular, continue to draw power after they have thrown. My measurements show that they draw about 0.5 amps at 12 volts. This is not likely to burn up the switch motor but I don't like a component being left on when it is not necessary.

The reason that I ask is that you could easily add another latching relay and two more reed switches to the reverse loop to throw the switch motors to the appropriate direction. The switch motors from Aristo and the Tourtoise draw little or no power after they have thrown. They would work quite nicely with the latching relay. LGB's switch motors would be much more likely to damage the contacts on the relay after an extended time.

Thanks

dave 



Dave,

My LGB switch motors draw nothing when they are not being actively thrown. They can't because no power is supplied to them except when they are toggled, either at the control panel, or at the proximate automation module.


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## dbodnar (Jan 2, 2008)

Posted By toddalin on 26 Oct 2010 10:29 AM 
Posted By dbodnar on 26 Oct 2010 07:21 AM 
Cliffy - Have you chosen switch motors to throw your switches? The reason that I ask is that some switch motors, LGB's in particular, continue to draw power after they have thrown. My measurements show that they draw about 0.5 amps at 12 volts. This is not likely to burn up the switch motor but I don't like a component being left on when it is not necessary.

The reason that I ask is that you could easily add another latching relay and two more reed switches to the reverse loop to throw the switch motors to the appropriate direction. The switch motors from Aristo and the Tourtoise draw little or no power after they have thrown. They would work quite nicely with the latching relay. LGB's switch motors would be much more likely to damage the contacts on the relay after an extended time.

Thanks

dave 



Dave,

My LGB switch motors draw nothing when they are not being actively thrown. They can't because no power is supplied to them except when they are toggled, either at the control panel, or at the proximate automation module.

Understood, Todd, but that was not my point - I was expanding on the circuit that I referred Cliffy to and explaining that a latching relay would easily accommodate switch movement but not so well with LGB switch motors.

dave


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## toddalin (Jan 4, 2008)

Posted By dbodnar on 26 Oct 2010 11:14 AM 
Posted By toddalin on 26 Oct 2010 10:29 AM 
Posted By dbodnar on 26 Oct 2010 07:21 AM 
Cliffy - Have you chosen switch motors to throw your switches? The reason that I ask is that some switch motors, LGB's in particular, continue to draw power after they have thrown. My measurements show that they draw about 0.5 amps at 12 volts. This is not likely to burn up the switch motor but I don't like a component being left on when it is not necessary.

The reason that I ask is that you could easily add another latching relay and two more reed switches to the reverse loop to throw the switch motors to the appropriate direction. The switch motors from Aristo and the Tourtoise draw little or no power after they have thrown. They would work quite nicely with the latching relay. LGB's switch motors would be much more likely to damage the contacts on the relay after an extended time.

Thanks

dave 



Dave,

My LGB switch motors draw nothing when they are not being actively thrown. They can't because no power is supplied to them except when they are toggled, either at the control panel, or at the proximate automation module.

Understood, Todd, but that was not my point - I was expanding on the circuit that I referred Cliffy to and explaining that a latching relay would easily accommodate switch movement but not so well with LGB switch motors.

dave 



Gotcha. Thanks.

I do "simulated" latching relays using two relays. One pulses the other and it latches. The one relay does the "pulsing" (set for ~1 second with a 555 chip) also fires the turnouts.


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## dbodnar (Jan 2, 2008)

Todd- I was just trying to keep it as simple and understandable as possible - if I were designing such a circuit from scratch I would use a PIC microcontroller or a PICAXE to take over all of the management & sensing duties - I'll save that for another time!

dave


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## CliffyJ (Apr 29, 2009)

Good point Dave, I certainly do not want all that needless current draw. I'm planning on the WA1 from Train-Li. I don't think it keeps drawing power, but maybe someone here knows?
Thanks,
Cliffy


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## CliffyJ (Apr 29, 2009)

Todd,

Cool, that means your relays all fit in one of those; wasn't quite sure. I don't suppose you have a picture?

I was planning on 2 pushbuttons -- mainly because I think they would look cool for night op's (they would be illuminated, via feedback from the WA1 internal circuitry, showing actual thrown position of the turnout). 

I've been looking at those regulators, and am trying to figure out how to employ them... so far, they look like something I'd buy, wire up, turn on, and sniff that unique aroma when a semiconductor's soul floats skyward... 

But thanks for the inspiration, I'm learning a lot here.

Cliffy


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## CliffyJ (Apr 29, 2009)

Hi again Dave,

You mentioned adding "another latching relay and two more reed switches to the reverse loop to throw the switch motors to the appropriate direction". I had expected it to be that straightforward, and maybe it is, but as I get into the schematic I don't see how that works. This is the core issue of my original post; so help me out here, obviously I'm missing something.

Approach 1: Things are wired so that the train always has to go thru the turnout via (say) the straight leg -- exactly as your latching relay diagram shows. And yes, you can easily add that other RS & K to throw the switch for the exiting of the loop. Here's the problem: how do you throw the switch back, to its straight-leg-default position? I don't think I can use another RS due to downstream train-switching activity that might mess with that. Maybe a timer? That's kinda tricky though...

Approach 2: Things are wired so that the train enters the loop from either direction (e.g., via Todd's circuit). In that case, the reed switches would need to "know" which position to throw the turnout to. This is why I was "ideating" earlier on the track-power-fed-via-diode RS & K method, or offset magnets / RS's (which now seems silly, due to breadth of magnetic field). 

Either way, how would you handle the RS's & K's?

Thanks!!

Cliffy


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## CliffyJ (Apr 29, 2009)

I don't think anyone answered my Stupid Question #1. Put mo' better: When a locomotive is going from left to right, is the "lower" rail always positive (except for the Bachmann loco switch that Todd pointed out) ? Or is it the opposite? Or...?


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 26 Oct 2010 02:54 PM 
Todd,

Cool, that means your relays all fit in one of those; wasn't quite sure. I don't suppose you have a picture?


But thanks for the inspiration, I'm learning a lot here.

Cliffy







I've not constucted the loop control. This came out of my mind as an alternative, but there is no reason that it will not work.

I have built several other similar type circuits and was just fixing one today (that's for another story) so I snapped some pics for you. This is my combination station leap frog and fueling stop module. The leap frog is where one train comes in, sets the two turnouts for the other train to leave and return, shuts off, and the other train starts up and leaves for its loop around the circuit. Then they alternate. There are reed switches at both ends on both tracks and the panel selects which reed switch depending on which way you want the trains to go (NB = North Bound, SB = South Bound, IL = Inner Loop, and OL = Outter Loop). I purposely wire some engines with the "Bachmann Reversal Switch" so they go different directions around the layout and people love it.

The other circuit controls another "fueling track" and I can have trains proceed at normal or slow speed and stop for water at the tower, or for diesel at the tank (S = Steam, D = Diesel). The pot allows me to adjust how long the trains stop and the red mark synchronizes the timing of the stop with the MP3 player (that I got from Dave Bodner) sound track if I so desire. 
It's all placed in a weatherproof box and sits trackside and can be turned on or off from my control panel.





And the leap frog is on another board. Note that there are actually 7 relays used for this circuit. Two 555 chips pulse their relays for 1 second, these then activate the larger relays that actually throw the turnouts for 1 second, and latch the relays sitting atop them to start/stop the trains. The 7th relay disconnects the circuit from the turnouts entirely, and from my control panel, except for that one second when the turnouts are actively being thrown. This keeps one turnout from "feeding back" through the other through the diode matrix when activated from the control panel.

[img] 
"How to Stuff a Wild Bikini"

[img]http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/Off-Load_Area/index_008.jpg /> 
Yeah, it all fits. Some foam keeps the spiders out.








/>



Now you see it...


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## kormsen (Oct 27, 2009)

Cliff,

lots of info given. to my likening a bit too complicated.

if you want something simple, just buy one switchmotor with the additional doublethrow switch from LGB. and optional two reed switches. (if you don't like to use the reeds, use short pieces of rail as contacts, like shown in the plan)

the disadvantage of this plan - one direction only in the loop.
if you want both directions, it gets a little less simple.
for this shown below, the switchmotor does not even have to be at the switch. a rubberband could hold the switch tongue in position too.


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## toddalin (Jan 4, 2008)

Posted By kormsen on 27 Oct 2010 05:05 AM 
Cliff,

lots of info given. to my likening a bit too complicated.

if you want something simple, just buy one switchmotor with the additional doublethrow switch from LGB. and optional two reed switches. (if you don't like to use the reeds, use short pieces of rail as contacts, like shown in the plan)

the disadvantage of this plan - one direction only in the loop.
if you want both directions, it gets a little less simple.
for this shown below, the switchmotor does not even have to be at the switch. a rubberband could hold the switch tongue in position too.













Nice to see that someone else has picked up on my Bump A.S.S. concept using the rail gaps.







What should be pointed out, and is not shown in your diagram, is that you need jumper wires for the rail to conduct electricity around the gaps so the trains don't loose power once they've passed the gap. Good job!


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## kormsen (Oct 27, 2009)

Posted By toddalin on 27 Oct 2010 10:48 AM 
What should be pointed out, and is not shown in your diagram, is that you need jumper wires for the rail to conduct electricity around the gaps so the trains don't loose power once they've passed the gap. 

right. i did not put that in the pic.

i have tried out your idea with the contact rails on a temporary test layout.
i love it, because in my last layout the only source of traincrashes were burnt reeds.(besides the cat)

and... i can use reeds and magnets for train related animations.


back to the wye thing: 
the whole point for me is, that everything shall run in auto mode.
given, that i got the half of the trains in reversed polarity and trains in both directions alternately use the one track sections between stations, the introduction of a "headstation" with a wye as part of the loop is a pain in the ... brain.


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## toddalin (Jan 4, 2008)

Posted By kormsen on 27 Oct 2010 04:27 PM 

back to the wye thing: 
the whole point for me is, that everything shall run in auto mode.
given, that i got the half of the trains in reversed polarity and trains in both directions alternately use the one track sections between stations, the introduction of a "headstation" with a wye as part of the loop is a pain in the ... brain.


Maybe I'm just not understanding what you are trying to accomplish.

Do you want each of the four trains running in one direction to consecutively run through the wye, turn around, and re-park, one at a time, until they are all turned around and re-parked..., then do the other four that were going the other direction, then restart them around the loop once the last train is in position? That could take some serious thought.










A little "mind expansion" and it occured to me how to do this for two stations and four trains (2 each direction) with the wye placed between the stations. Additional stations would have the two proximate stations in the way. If that's of interest, I can describe it.


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## kormsen (Oct 27, 2009)

Posted By toddalin on 27 Oct 2010 05:57 PM 

Do you want each of the four trains running in one direction to consecutively run through the wye, turn around, and re-park, one at a time, until they are all turned around and re-parked..., then do the other four that were going the other direction, then restart them around the loop once the last train is in position? That could take some serious thought. 



nope!
what i got is eight stations. four and four trains of different polarity. 

step one:
trains from station one set out to station two and station eight.
trains from station three set out to station two and station four.
trains from station five set out to station four and station six.
trains from station seven set out to station six and station eight.


step two:
trains from station two set out to station one and station three.
trains from station four set out to station three and station five.
trains from station six set out to station five and station seven.
trains from station eight set out to station seven and station one.

repeat steps....

so far it is easy. no toggling switches (turnouts), just one train starting another.

but if i replace one station by two wyes.... or do i have to replace two stations by wyes??
must both wyes be doubletracked? the track between the two wyes must be double track? 
and so on....

i will never find that one out, without setting it up for test.

edit:

so no parking of trains, but at one step two trains coming in, at the other step two trains going out.


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## toddalin (Jan 4, 2008)

Posted By kormsen on 28 Oct 2010 03:43 AM 
Posted By toddalin on 27 Oct 2010 05:57 PM 

Do you want each of the four trains running in one direction to consecutively run through the wye, turn around, and re-park, one at a time, until they are all turned around and re-parked..., then do the other four that were going the other direction, then restart them around the loop once the last train is in position? That could take some serious thought. 



nope!
what i got is eight stations. four and four trains of different polarity. 



Is it actually eight separate stations along the entirety railline, or are there actually four separate station areas that are "double tracked " at each station like a passing siding? If the latter, as I noted, this can be done with two stations (and four trains two facing in each direction) so if you used two wyes, you could do it for four stations (eight sidings). If this is the case, I can describe the circuitry.

Also on this topic, you noted that you have _*successfully*_ been using the 16 vac through the track gaps, through the diodes, to drive the turnout. My question is..., is this the same ac source that drives your dc source for the trains, or is this a totally separate ac transformer?

I ask because this is similar to using a common rail that we use. But early testing demonstrated that to use the common rail, all power supplies have to be independant. In the past when I've taken the ac source, rectified it, throttled it through the TE, and put it on the rails to drive the trains, and also try to put one leg of _this same ac source_ on the common rail, I've popped the fuse. Of couse an independant ac source is perfectly viable.


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## kormsen (Oct 27, 2009)

Posted By toddalin on 28 Oct 2010 10:07 AM 
Is it actually eight separate stations along the entirety railline, or are there actually four separate station areas that are "double tracked " at each station like a passing siding? If the latter, as I noted, this can be done with two stations (and four trains two facing in each direction) so if you used two wyes, you could do it for four stations (eight sidings). If this is the case, I can describe the circuitry. 
Also on this topic, you noted that you have _*successfully*_ been using the 16 vac through the track gaps, through the diodes, to drive the turnout. My question is..., is this the same ac source that drives your dc source for the trains, or is this a totally separate ac transformer?

I ask because this is similar to using a common rail that we use. But early testing demonstrated that to use the common rail, all power supplies have to be independant. In the past when I've taken the ac source, rectified it, throttled it through the TE, and put it on the rails to drive the trains, and also try to put one leg of _this same ac source_ on the common rail, I've popped the fuse. Of couse an independant ac source is perfectly viable.


it is eight times this: (well, a little bit longer...)










(the switch has to be a single throw.)

so by your way of counting i got 8 stations with 16 sidings for the twice 4 trains. (with just four stations i would have to run the clockwise and the counterclockwise alternately.)

at first thought, it must be more or less this way:
(supposing, the wyes replace stations 2 and 3)

first step:
station one sends trains to wye A and to station eight.
wye B sends trains to wye A and station four.
station five sends to station four and six.
station seven to six and eight.

second step:
wye A sends to station one and wye B.
station four sends to wye B and station five.
station six sends to stations five and seven.
station eight sends to stations seven and one.

this demands, that the "outstanding" legs of the wyes are double track. further it demands, that one of the outgoing trains from each wye must be restrained by a timer.

about fuseblowing...
as i got a dozen small powerpacks, i used one pack for dc and another exclusively for the ac to the contacts.
as my plan above indicates, i did not rectify the ac before the railcontacts, but between the railcontacts and the switchmotor. (following the way, the LGB-epl system is wired. they put the diodes at the out from the reed to the switchmotor)
what i did not use was the transistor (or whatever it is) that LGB has in paralell to the reed.


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## kormsen (Oct 27, 2009)

well, reading my own post, i realized, that what i got in mind are no wyes! 

i will draw a plan over the weekend.


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## toddalin (Jan 4, 2008)

Posted By kormsen on 28 Oct 2010 01:47 PM 
about fuseblowing...
as i got a dozen small powerpacks, i used one pack for dc and another exclusively for the ac to the contacts.
as my plan above indicates, i did not rectify the ac before the railcontacts, but between the railcontacts and the switchmotor. (following the way, the LGB-epl system is wired. they put the diodes at the out from the reed to the switchmotor)
what i did not use was the transistor (or whatever it is) that LGB has in paralell to the reed.













Gotcha. That's what I thought (a totally independant ac power supply). I believe that a caveat to this way of doing it is that the ac supply has to be independant of the ac that is rectified and throttled to drive the trains. You may want to test this theory out and document your findings when you write your new methodology for all too see.









BTW, I believe the other component on the LGB board is either a capacitor to absorb the voltage spike, or a metal oxide varistor to disipate it through the other leg. This increases the life of the reed. These are usually pretty reliable assuming that you only drive one turnout motor at a time with them. They have a limited life driving two turnouts.


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## kormsen (Oct 27, 2009)

yeah, that is, what they told me. they mentioned that these things take away some of the load from the reed. 

but i did not find a significiant difference in lifespan between reeds that drive one switch and those that drive two. 
when i tried to drive three switches from one reed, seemingly the current was not strong enough to work reliable. 

i simply do NOT use rectified AC (rectified by me, that is) to drive my trains. the european transformer-regulators come either with regulated DC output only or they come with regulated DC plus unregulated AC output. 

btw - do the powerpacks from computers have DC or AC output? i got a couple of elder, smaller ones, that ask me to be used for my layout...


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## toddalin (Jan 4, 2008)

Posted By kormsen on 28 Oct 2010 03:28 PM 

the european transformer-regulators... or they come with regulated DC plus unregulated AC output. 





Yes, these are the very ones I am referring to..., a transformer that has both regulated dc and unregulated ac out of the same case, off the same wall plug. They actually share the same ac source and I believe such a unit will pop the fuse if you try to run your turnouts as shown using this ac tap if you have dc on the rails simultaneously. This is what needs documentation. 
I believe computer supplies are typically dc with a 5 volt tap and maybe other voltages available as well.


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## CliffyJ (Apr 29, 2009)

Todd, Dave and all who've been helping me, 

First off, thanks again; second, here's my shot at rollin' my own. 

Except for it not working (preemptive comment, if and when fatal flaws are pointed out)







, the benefits are these: 
- ability to enter loop from either direction
- ability to reverse train direction while in the loop (couldn't see how to do that with the rectifier approach, Dave), and make the main line cooperate in polarity during the exit
- auto-throwing of the switch motor (while NOT interfering with the happy balance between loop and mainline polarities)

So here goes... I renewed my subscription here, just to put this crappy jpeg in...







:
No seriously, I was going to renew anyway...









A few notes are in order.
Red is track power, green is signal.
Main line and both return loops have a dedicated latching power relay, to manage their respective polarities. These relays start retailing at about $15 each (with socket). 
Boy, that IS a crappy jpeg. If there's any joy here, I promise to improve on it.
The "turnout correction" relay could have been combined with the rev. loop relay, but Todd was right, latching relays with more than 2 poles are very pricey.

Any comments? Fatal flaws seen? Arguments for a better method, in view of the "benefits list" above?

Thanks in advance for your wisdom,
Cliffy


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 28 Oct 2010 03:47 PM 


Todd, Dave and all who've been helping me, 

First off, thanks again; second, here's my shot at rollin' my own. 

Except for it not working (preemptive comment, if and when fatal flaws are pointed out)







, the benefits are these: 
- ability to enter loop from either direction
- ability to reverse train direction while in the loop (couldn't see how to do that with the rectifier approach, Dave), and make the main line cooperate in polarity during the exit
- auto-throwing of the switch motor (while NOT interfering with the happy balance between loop and mainline polarities)

So here goes... I renewed my subscription here, just to put this crappy jpeg in...







:
No seriously, I was going to renew anyway...









A few notes are in order.
Red is track power, green is signal.
Main line and both return loops have a dedicated latching power relay, to manage their respective polarities. These relays start retailing at about $15 each (with socket). 
Boy, that IS a crappy jpeg. If there's any joy here, I promise to improve on it.
The "turnout correction" relay could have been combined with the rev. loop relay, but Todd was right, latching relays with more than 2 poles are very pricey.

Any comments? Fatal flaws seen? Arguments for a better method, in view of the "benefits list" above?

Thanks in advance for your wisdom,
Cliffy




Well whether it works or not, I'm already impressed! Most people never get this far. It would be _far easier to follow_ if you would provide a narrative of a trip through the loop in either direction (or at least what you think is happening). See my post back on page 1 for a sample:

e.g., "...Follow along the diagram as you take a ride through the loop and see what happens." 

Still, at first glance, I think I see a few problems. As shown with the train is proceeding from right to left, you appear to have thrown the turnout with the toggle for the train to take the left route into the turnout. The train passes the reed switch and current flows to the turnout "R" trigger and turnout swings into position as it should.

Current also flows to the the mainline latching relay and latches the armature toward the left. But that's where it's already at, so you've not effected a change of mainline polarity. It would appear at first glance that you have the reed switch leading to the wrong relay coil and that you would want to pull the armature in the other direction.

A second glance and the problem would appear to go bit deeper.

Assume the train proceeds from left to right and user toggles left route as shown. The train proceeds through in a clockwise direction and while in the loop throws the turnout to the right position and the train proceeds through. Great.

Assuming the afformentioned mainline latching relay coil is changed, the mainline changes polarity and the train proceeds on its way. Still great.

The train does the same thing on the other side of the layout and is now headed back. Looking good!

The train now comes back to the turnout and now proceeds toward the right side (counterclockwise), because thats where you left the turnout and the user has not toggled anything because he was sipping his beer. Wait!

There has been no "pulse" that I can see, other than the control panel toggles, that has/can change the polarity of the loop, so "electrically," trains still want to proceed through in a clockwise direction through the loop and this causes a short circuit when it passes the turnout.

If you took the feed lines to the loop section from the mainline after it had been through its latching relay, it would change polarity when the mainline changes and alleviate this problem. But you certainly don't want to change the polarity of the loop when the train is in it, which is what would happen when the mainline would flip polarity. So the loop needs to change polarity at the same time that the mainline changes polarity so the trains continue in the direction they were going. If you go back to my diagram on page 1, you can see how I've handled this and can take a cue from there. Another way to handle it would be to use a reed switch in each loop to change the loop polarity relay of the loop on the other side of the railroad. 

Thanks


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## kormsen (Oct 27, 2009)

you two lost me completely. this is too complex for me. 


edit:
in my understanding one needs the rectifying diodes in the loop. period.
so if one wants to use the loop in different directions, one has to use two sets of rectifying diodes and a switch between them and the loop, to give the loop different polarity when changing the direction of the entrance switch (turnout) to the loop.


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## kormsen (Oct 27, 2009)

just for the fun of it:
if cliff would not use a loop, but a wye.
contact "A" puts the mainline polarity(switch "I") and the wye polarity(switch "2") as shown in the plan and the mainswitch/turnout of the wye for direction "1". 
contact "B" reverses the switch "II".(movement "2")
the two secondary turnouts don't need to be switched. they are set for the outgoing trains and cut open by the ingoing trains.
contact "C" changes back the polarity in the wye and contact "D" reverses the mainline and changes the turnout for movement "3".


one could use reeds, or as i marked the railcontacts.
if using railcontacts it is important, that all contacts are on the same rail (as shown) from an inside the wye viewpoint! (as in movement "2")


contact "A" must be coordinated with the loop or wye on the other end of the mainline.
observation - for a more realistic behaviour of the trains i would put timers behind contacts "B" and "C".


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## CliffyJ (Apr 29, 2009)

Right you are, Todd: my mainline coil triggers were backwards!
Thanks for your narrative; and yes, I need to explain it more thoroughly.
To your main point though:

"The train now comes back to the turnout and now proceeds toward the right side (counterclockwise), because thats where you left the turnout and the user has not toggled anything because he was sipping his beer. Wait! There has been no "pulse" that I can see, other than the control panel toggles, that has/can change the polarity of the loop, so "electrically," trains still want to proceed through in a clockwise direction through the loop and this causes a short circuit when it passes the turnout."

That's why I put the diodes in (DL/DR): the reed switch triggers the main line relay, and throws the switch; but it does not trigger the loop polarity relay. 
If I'm thinking it out properly, when the train comes back from the other sideof the layout as you describe: the switch is still thrown to the right, and the loop relay hasn't been triggered either. Nor has any toggle been thrown. 
So the train enters this loop on the right, and...
ooops...
dang, you're correct: I WAS sipping a beer! How did you know?
Also, the main line got reversed by the other side's circuit -- and THIS loop's not been flipped accordingly. Double dang!
Now I see what you mean. 

For now, I'll put in the whole circuit, and see what opposite-end-reed-triggering of the loop polarity relays does.
So back to the drawing board!

Thanks Todd,

Cliffy


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## CliffyJ (Apr 29, 2009)

Here's the full thing, now with triggering from opposite loops. Not sure if all the relay cantacts are shown properly...


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## CliffyJ (Apr 29, 2009)

Well Todd, I think I have about the same number of relay coils as you did... 

Does your circuit work with rev loops at both ends? 
How about a third rev loop in the middle (which my layout has to have)? 
My brain hurts.... 
The main issues that I had with your approach were these:
- Complexity (which now doesn't seem that complex...)
- You don't show how to throw the switch machine motor

So Todd, I'll cry uncle on the switch logic.

BUT: but can you reliably integrate the switch machine triggers?

Aha!










Yes indeed! It was only because I incorporated the stinking switch machines that my coil count went from six to ten -- and you have yet to add those in! 
But even so, my approach may not work, because of other things you may spot... and mine has a whole boatload more of wire...









So... maybe switch machines are not necessary, if the turnout is always intended for a default position. I wish this were true, but after a LOT of inquiry, no one can tell me that it is.

So if springs are ok enough to throw the turnout, with lightweight cars, someone please 'splain to me how to pull it off. 
In the mean time though, I've got to assume active throwing of the turnout for loop exiting. This is because I'm modeling the Virginia & Truckee, Virginia City branch, where long strings of (comparatively) light ore cars need to be possible.

Regardless, I'm counting on you Todd to show how you work your active switch machines in.










Cliffy


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 29 Oct 2010 02:41 PM 
Well Todd, I think I have about the same number of relay coils as you did... 
Does your circuit work with rev loops at both ends? 
How about a third rev loop in the middle (which my layout has to have)? 
My brain hurts.... 


It will..., but like yours, it would also need a couple more to control the interaction. But I specify common, surplus relays, and as you found, they are lots cheaper and you can probably get all five for each loop for less than the cost of one latching relay. 

How do you intend to do the third reverse loop? Would this be done like a wye with two tracks leading in/or? Obviously, most anything can be done using "relay logic," but often with certain limitations.

One limitation of using common relays rather than latching relays, is that if you shut off the power to the relays during operation, they go back to their "default" state whereas a latching relay will stay were it was last latched. This can be both/either a disadvantage and an advantage depending on the situation.

I've not had time to get into your most recent schematic yet. (I'm helping a neighbor wire for a halloween party.)

Yes, we _should be able_ to figure a way for it to throw your chosen switch machines.


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## CliffyJ (Apr 29, 2009)

Hi Kormsen,

"in my understanding one needs the rectifying diodes in the loop. period."

A couple of days ago, I would have agreed; but I couldn't make it work. Not that I know what I'm doing, but it's just that with my limited understanding, no-workie. Interesting idea you have about two rectifiers though; but wouldn't that require managing relays, etc., I suppose?

To some degree, I'm weighing all this against battery-power. But I figure that no matter how the trains are powered, one must manage the turnouts. For me, the latter means remote op's: when it's dark, I don't want to be crawling to a ground throw with a flashlight; and even in the day, I don't want to risk damage to surrounding structures. 

For now though, track power is on the drawing board, and as automatic control of trains as I can cheaply get. 

Best regards, and thanks for all your ideas,
Cliffy


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## CliffyJ (Apr 29, 2009)

Didn't mean to pull a fast one: you replied to my original post, just as I was editing / expanding on it!


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 29 Oct 2010 10:28 AM 








Here's the full thing, now with triggering from opposite loops. Not sure if all the relay cantacts are shown properly...



I think this would work. If not, it's damn close and I'm impressed!

It appears that trains would automatically alternate their directions through the loops, unless toggled by the operator, which is what mine would do, and the polarities match up. Further study would be required to find a flaw.


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## kormsen (Oct 27, 2009)

Posted By CliffyJ on 29 Oct 2010 03:10 PM 
Hi Kormsen,

"in my understanding one needs the rectifying diodes in the loop. period."

A couple of days ago, I would have agreed; but I couldn't make it work. Not that I know what I'm doing, but it's just that with my limited understanding, no-workie. Interesting idea you have about two rectifiers though; but wouldn't that require managing relays, etc., I suppose?

To some degree, I'm weighing all this against battery-power. But I figure that no matter how the trains are powered, one must manage the turnouts. For me, the latter means remote op's: when it's dark, I don't want to be crawling to a ground throw with a flashlight; and even in the day, I don't want to risk damage to surrounding structures. 

For now though, track power is on the drawing board, and as automatic control of trains as I can cheaply get. 

Best regards, and thanks for all your ideas,
Cliffy


managing relais? - no. i do all my switching with either original LGB switchmotors or with the switches from central locking systems for cars. (the LGB switchmotors got the advantage, to have these snap on additional switches- so i dont have to either install micro switches or to make sliding contacts myself)

the alternating rectifiers are peanuts. the problems are your light cars. that means, the change of rectifiers can not be directly coupled to the turnout of the loop. (before a train leaves the loop, the turnout has to change direction, without changing polarity inside the loop.)

if you want enter the loop in alternating directions you will end up with a whole lot of gizzmos installed.


battery? - well, each as he wants. I personally prefer to work now, planning and installing everything and not to do nothing but bragging around in the future, when i'll have visitors to the layout.

how could i brag fullhearted, if i would have to control everything by hand?


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## CliffyJ (Apr 29, 2009)

Hi again Todd, 

Back to your schematic and narrative: I'm confused on one point. 
To move the train from left to right, you have + on the 'lower rail' (right?), which feeds back thru R3P4 and then to the outer rail of the loop -- which would be on the opposite side, and cause a short once the train passed thru the switch. So I must be missing something, could you help me out? It must work, since you're using the thing!! 

You know how you can remember / understand a map better if you draw it out for yourself? Well, that's what I'm doing with your schematic. I'm slowly getting it!! 

One other question, how does the circuit work with the same thing (reverse loop) on the other end of the main line? Can you more or less copy it over? 

Regards, 
Cliffy


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 02 Nov 2010 04:02 PM 
Hi again Todd, 

Back to your schematic and narrative: I'm confused on one point. 
To move the train from left to right, you have + on the 'lower rail' (right?), which feeds back thru R3P4 and then to the outer rail of the loop -- which would be on the opposite side, and cause a short once the train passed thru the switch. So I must be missing something, could you help me out? It must work, since you're using the thing!! 

You know how you can remember / understand a map better if you draw it out for yourself? Well, that's what I'm doing with your schematic. I'm slowly getting it!! 

One other question, how does the circuit work with the same thing (reverse loop) on the other end of the main line? Can you more or less copy it over? 

Regards, 
Cliffy 



Actually, no, I'm not using it. I only dreampt it up and you would be the first.

Yes, it would be a copy on the other end and there would need to be an intermediate relay. Let me take a look and I'll get back to you.


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 02 Nov 2010 04:02 PM 
Hi again Todd, 

Back to your schematic and narrative: I'm confused on one point. 
To move the train from left to right, you have + on the 'lower rail' (right?), which feeds back thru R3P4 and then to the outer rail of the loop -- which would be on the opposite side, and cause a short once the train passed thru the switch. So I must be missing something, could you help me out? It must work, since you're using the thing!! 

You know how you can remember / understand a map better if you draw it out for yourself? Well, that's what I'm doing with your schematic. I'm slowly getting it!! 

One other question, how does the circuit work with the same thing (reverse loop) on the other end of the main line? Can you more or less copy it over? 

Regards, 
Cliffy 



You are correct! The two wires that come out of R3P3 and R3P4 should be reversed at the track. Thanks for catching that. It's hard to find peer review for this stuff.

Yes, both loops are done the same. I believe that you can use the latching relay as you had proposed to control the area between the two loops. If you would rather use ordinary relays, I can give it some thought. BTW, if you use 12 volt relays, you can use the same power supply you use for your turnouts and may even be able to use the same pulses that trigger these relays to trigger your turnouts.

Thanks again for pointing the error out.


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## CliffyJ (Apr 29, 2009)

Thanks Todd, it's making sense for me more and more. And I'm glad to be of help.

As I was saying earlier, I'm trying to redraw your circuit in my own drafting method -- not that this version is any better, only that it's forcing me to better understand. 

So, not sure if I'm exactly doing it right, but here it is:











I've come to understand better the "latching" relay pairs; very cool! 

In addition to mixing everything around







, I've combined relays 3 & 4 (as you implied in your writeup). Also, I've applied the circuit specifically to the WA1 and illuminated PB's. 

Other than that, I'm on the verge of figuring out how this works...







... and it's seeming simpler than mine. 

However: Is there ever an issue with your relay pairs burning out though, seeing that at least one (on one end of the layout or the other) is pretty much energized all the time? If that's a potential issue, might one convert your circuit to a latching-relay approach?

Thanks for all the education, and best regards,

Cliffy


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 03 Nov 2010 04:27 PM 
Thanks Todd, it's making sense for me more and more. And I'm glad to be of help.

As I was saying earlier, I'm trying to redraw your circuit in my own drafting method -- not that this version is any better, only that it's forcing me to better understand. 

So, not sure if I'm exactly doing it right, but here it is:











I've come to understand better the "latching" relay pairs; very cool! 

In addition to mixing everything around







, I've combined relays 3 & 4 (as you implied in your writeup). Also, I've applied the circuit specifically to the WA1 and illuminated PB's. 

Other than that, I'm on the verge of figuring out how this works...







... and it's seeming simpler than mine. 

However: Is there ever an issue with your relay pairs burning out though, seeing that at least one (on one end of the layout or the other) is pretty much energized all the time? If that's a potential issue, might one convert your circuit to a latching-relay approach?

Thanks for all the education, and best regards,

Cliffy





Thanks.

I've given it some thought and it's even easier that I had originally imagined. If you simply "cascade" the two sets of loop controls, the mainline will take care of itself! If you build two loop circuits, simply run the output from R1P3 and R1P4 to the inputs of R1P3 and R1P4 (where it shows Power Pack) of the other loop controller. Then run the output of that R1P4 to the track. All other connections are as previously shown, but correcting for the crossed wire into the loop that you had pointed out. In this case, the power pack input to R3P3 and R3P4 must come from the track (i.e., after the second system in the cascade) and not directly off of R1 of the first system after the power pack to assure proper polarity through the loop.

Think about it. Say when a relay is "relaxed" is the Normal state and when just one is activated is the Reversed state. Say trains go to the right in the Normal state and to the left on the Reversed state. When both controllers are relaxed, the train goes to the right and is reversed in the loop that also throws R1. So now one control is Normal and one is Reversed so we have a net reversal and the train goes to the left. Now the train enters the other loop and that reverses the mainline. So the mainline is reversed from the controller in the first loop and reversed by the controller in the second loop so again the train proceeds to the right. Again, this should go on and on.

With respect to using your switch machines, it is a very simple matter to tie the two contacts from R3P2 to your machines and when these fire, your machines fire in the proper direction. We can even use the Bump A.S.S. gaps here and avoid the reed switches altogether allowing any train to run the loop, even without a magnet. Again too easy.

When it comes to ganging/splitting relays, what makes most sense from both and economic and operating standpoint is to use two dpdt relays with parallel coils to replace R1 and I would keep R3 as two relays, a dpdt and a 3pdt. Then I could use economical dpdt 10 (or more) amp relays to handle the current used to power the trains, and 1 amp replays to operate the logic. 

I really wouldn't worry about the lifespan of the thrown relays, and they are extremely cheap surplus to replace..., so if this worries you, buy spares. The only relays that I've had fail from continual use is a latching relay in my "leap frog" that was replaced with one that continuously throws when latched and opened by a second relay, similar to what I've done here.


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## CliffyJ (Apr 29, 2009)

So, Todd, the plot thickens!

Thanks for your description of the opposite-end treatment; I'll be working on it this weekend.

For now, I'd like to make sure I have your "latching relay" curcuit fully understood. That's why I ganged R4 with R3: It helped me distill things and ferret out better how you are doing your latching. I'll split it back out later; but here's my conclusions. 
[*]By 'latching,' I had expected two inputs for the pairs; hence my confusion. What you seem to have here though is a single (momentery) input, alternating-action, latching relay (set).[*]The first impulse "locks" the contacts in the (non-normally) energized state; the second impulse unlocks and returns things to their (normally) non-energized state. Would you concur?[*]R3P2 (your diagram; K3P5 on mine) is acting as the "traffic cop" for which of the two reed switches might have a say.[*](Sorry for the K designations, R's are usually reserved for resistors, but I should have ignored that fact for this discussion and kept with R's)[*]The reed switches are momentary triggers for mainline reversal (via your R1&2, my K1&2)[*]Your turnout toggle (my PB's): [*]trigger the switch machine, and[*]provide momentary signals that reverse (lock if unlocked, unlock if locked) what has been going on for loop polarity[/list][/list] In regards to the loop polarity, which is what R3/4/5 is all about (my K3&4). It seems that this portion of your circuit only kicks in if the non-default leg of the loop is selected for the train. In this case, the switch machine is thrown; loop polarity is reversed; and the "traffic cop" R3P2 (my K3P5) reverses what the reed switches will potentially trigger. Or something like that. Would you concur? Am I getting closer?

As to your suggested implementation for the opposite loop, it strikes me that your current R1/2 set is all that is needed for mainline polarity, and that perhaps the only thing that needs to be "mirrored" is your R3/4/5 side of the circuit.... somehow? Maybe with a couple of diodes?

To that end, that is, overall design philosophy of the whole layout (with whatever number of reversing loops -- mine will have 3), one might almost be able to back away from the whole thing and disregard the "latching" elements of the circuit. That is, as long as one understands the "traffic cop" interplay with the reed switches and relays, and the alternating function of your "latching" relay sub-circuits, one can focus exclusively on track power and reed signal. 


But that's for another evening!

I would agree with your stated approach of power vs. signal relay splitting; I tried to do that in my other circuit, for the cost reasons you mention. Also, I like your BASS alternative to reeds; simpler the better! Whatever the 'final' circuit is, two or more reversing loops and all, the thing has to be checked for multiple relay hits from all those wheels. Seems like your circuit takes it though.


Best regards, and thanks once again,

Cliffy


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 04 Nov 2010 03:22 PM 
So, Todd, the plot thickens!

Thanks for your description of the opposite-end treatment; I'll be working on it this weekend.

For now, I'd like to make sure I have your "latching relay" curcuit fully understood. That's why I ganged R4 with R3: It helped me distill things and ferret out better how you are doing your latching. I'll split it back out later; but here's my conclusions. 
[*]By 'latching,' I had expected two inputs for the pairs; hence my confusion. What you seem to have here though is a single (momentery) input, alternating-action, latching relay (set).[*]The first impulse "locks" the contacts in the (non-normally) energized state; the second impulse unlocks and returns things to their (normally) non-energized state. Would you concur?[*]R3P2 (your diagram; K3P5 on mine) is acting as the "traffic cop" for which of the two reed switches might have a say.[*](Sorry for the K designations, R's are usually reserved for resistors, but I should have ignored that fact for this discussion and kept with R's)[*]The reed switches are momentary triggers for mainline reversal (via your R1&2, my K1&2)[*]Your turnout toggle (my PB's): [*]trigger the switch machine, and[*]provide momentary signals that reverse (lock if unlocked, unlock if locked) what has been going on for loop polarity[/list][/list] In regards to the loop polarity, which is what R3/4/5 is all about (my K3&4). It seems that this portion of your circuit only kicks in if the non-default leg of the loop is selected for the train. In this case, the switch machine is thrown; loop polarity is reversed; and the "traffic cop" R3P2 (my K3P5) reverses what the reed switches will potentially trigger. Or something like that. Would you concur? Am I getting closer?

As to your suggested implementation for the opposite loop, it strikes me that your current R1/2 set is all that is needed for mainline polarity, and that perhaps the only thing that needs to be "mirrored" is your R3/4/5 side of the circuit.... somehow? Maybe with a couple of diodes?

To that end, that is, overall design philosophy of the whole layout (with whatever number of reversing loops -- mine will have 3), one might almost be able to back away from the whole thing and disregard the "latching" elements of the circuit. That is, as long as one understands the "traffic cop" interplay with the reed switches and relays, and the alternating function of your "latching" relay sub-circuits, one can focus exclusively on track power and reed signal. 


But that's for another evening!

I would agree with your stated approach of power vs. signal relay splitting; I tried to do that in my other circuit, for the cost reasons you mention. Also, I like your BASS alternative to reeds; simpler the better! Whatever the 'final' circuit is, two or more reversing loops and all, the thing has to be checked for multiple relay hits from all those wheels. Seems like your circuit takes it though.


Best regards, and thanks once again,

Cliffy 











Sounds like you have a firm grasp of everything. Once you understand these basic "relay modules" and how to make them interact, you realize that most things can be done using this logic. (They used to build computers this way.)

No additional diodes should be necessary. Just build the same unit twice and cascade them as I noted previously. Actually, I was thinking about it and I think you could cascade as many of these as you want and have any number of loops you desire and again, the mainline will take care of itself. Just remember that when the turnouts are throwing, you're reversing the current out there and if you have other trains on the mainline, they'll start going backwards unless they are in designated areas (i.e., areas that we would isolate or within the other loop at that moment).


The first time the user powers up the system they should either make sure that the turnouts are set to the straight (default) position, or that the user toggles them the first time around, just to ensure that the train does not take the wrong direction (curved route) without resetting the system to that direction. Other than that, just keep feeding it the 12 volts, even when you shut down the throttles to the trains, to keep the relays latched.


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## CliffyJ (Apr 29, 2009)

Thanks for the additional pointers, Todd.

To one point, you said: "No additional diodes should be necessary. Just build the same unit twice and cascade them as I noted previously." I don't think that's exactly correct. Unless i'm missing something, your R1/R2 is the "mainline polarity management relay set", and is merely accepting alternating momentary inputs -- from whatever source. You're thinking 'cascade,' but I'm thinking 'modular'. This is why I suggested "mirroring" only your R3/4/5 set (my K3/4). Here is my interpretation:










From this exercise, it is seeming to me that your circuit involves two primary relay groupings: loop polarity management, and mainline polarity management. Your "LPM" (if you will permit me) further decides which reed switch in that loop gets to trigger your (again, please permit me) "MPM" (your R1/2). In the above, we have two "LPM's", each deciding upon which of their reed switches perform the mainline reversal. Further (and I know you know this; I'm just talking to myself), the "MPM" can receive multiple inputs (e.g., a third reverse loop or wye).

Two questions: is this a fair assessment? Second, I don't see yet how this method works with multiple signal-triggers to the "MPM" from a given loop's reed switch. Put differently, if I use your "BASS" approach (which I really like, it's so simple), won't all those wheels keep your R1/R2 pair flipping one way and then the other, reversing the main line repeatedly? I hope not, I'm counting on this nice, elegant circuit to work, Bro! But please 'splain to me why that won't happen.

Thanks for your continued engagement of this issue,
Cliffy


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## kormsen (Oct 27, 2009)

i know, that planning is fun.
but somehow the plans we got in this thread seem very complicated.

if that is necessary, why could they do it so simple?
(or do they have a mistake in their plan?)


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## CliffyJ (Apr 29, 2009)

Todd, maybe I should better explain where I'm coming from. So far, (and thanks to you Todd, and Dave, and others here), I've been able to progress my latching-relay circuit to the following point:











As far as I can prognosticate to this point, it deals with all the complaints I began with on this thread. However, I'm quite ready to admit that the circuit has issues. 
[*]As you've pointed out: latching relays are more expensive, and they go bad. [*]I really like the simplicity of your alternating-input trigger method[*]Your circuit appears to have the least i/o for a "reverse loop control module"[/list] For these reasons, I abandoned my approach, and started afresh with yours. And have been distilling yours down into a versatile application that I can understand and implement over the long hual. So, I'm going to continue to press towards a modular approach in our reparte, whereby a person can build such and such a module, each having these guts, and have the overall system sing together... somehow. The reason for me is that I have planned several loop-to-loop layout circuits, and will (eventually) need them to communicate with one another -- in a manner that my (degrading!) memory / comprehension can deal with. 

Thanks,
Cliffy


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## CliffyJ (Apr 29, 2009)

You're right, Kormsen, it looks all too simple -- and should be!
And I thank you for your post here, and directing me to LGB's manual.
But unless I'm missing something, one has to acquire all these wonderful LGB devices to make it work. Devices that are no longer in production, and for which one has no detailed schematic info. 
But maybe you are aware of schematics for the TRAFO, the 17100, the 51750, and the switch machine? Maybe I can ferret it out...?
Sorry for sounding argumentative and being dense,
And thanks for those great diagrams,
Cliffy


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 05 Nov 2010 03:43 PM 
You're right, Kormsen, it looks all too simple -- and should be!
And I thank you for your post here, and directing me to LGB's manual.
But unless I'm missing something, one has to acquire all these wonderful LGB devices to make it work. Devices that are no longer in production, and for which one has no detailed schematic info. 
But maybe you are aware of schematics for the TRAFO, the 17100, the 51750, and the switch machine? Maybe I can ferret it out...?
Sorry for sounding argumentative and being dense,
And thanks for those great diagrams,
Cliffy



These devices are still marketed under the Piko name, except that Piko says they were improved for water-tightness, so that is still a very viable way to do this.

But, with simplicity comes cost. And while that LGB/Piko devices are cheaper than something like the TrainMaster, etc., they are still more costly than going with relays (which can also be more "powerful" both from a logic standpoint as well as their ability to transfer current), unless you are already using the switch motors for the turnouts. Even then, relays are cheaper than the supplemental switch contacts and can be driven off of the EPL current that drives your turnout. I do this with 24 volt relays using a diode and capacitor to rectify and boost the ac current. The relays are also more reliable than the EPLs in situations where it is imperative that they work, and the turnouts are subject to wheel bumping, dirt, etc. that may interfere with the point transfer (especially on my AristoCraft turnout).


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 05 Nov 2010 02:38 PM 
Thanks for the additional pointers, Todd.

To one point, you said: "No additional diodes should be necessary. Just build the same unit twice and cascade them as I noted previously." I don't think that's exactly correct. Unless i'm missing something, your R1/R2 is the "mainline polarity management relay set", and is merely accepting alternating momentary inputs -- from whatever source. You're thinking 'cascade,' but I'm thinking 'modular'. This is why I suggested "mirroring" only your R3/4/5 set (my K3/4). Here is my interpretation:










From this exercise, it is seeming to me that your circuit involves two primary relay groupings: loop polarity management, and mainline polarity management. Your "LPM" (if you will permit me) further decides which reed switch in that loop gets to trigger your (again, please permit me) "MPM" (your R1/2). In the above, we have two "LPM's", each deciding upon which of their reed switches perform the mainline reversal. Further (and I know you know this; I'm just talking to myself), the "MPM" can receive multiple inputs (e.g., a third reverse loop or wye).

Two questions: is this a fair assessment? Second, I don't see yet how this method works with multiple signal-triggers to the "MPM" from a given loop's reed switch. Put differently, if I use your "BASS" approach (which I really like, it's so simple), won't all those wheels keep your R1/R2 pair flipping one way and then the other, reversing the main line repeatedly? I hope not, I'm counting on this nice, elegant circuit to work, Bro! But please 'splain to me why that won't happen.

Thanks for your continued engagement of this issue,
Cliffy










We've been setting up the Del Oro Pacific for the SWGRS today and the show uns through Sun. I'll have to take a look at this and get back to you. I'm certain that as I had it it will function properly just using multiple identical untis, and it may also be able to do this with just the 1 relay just as well.


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 05 Nov 2010 02:38 PM 
Thanks for the additional pointers, Todd.

To one point, you said: "No additional diodes should be necessary. Just build the same unit twice and cascade them as I noted previously." I don't think that's exactly correct. Unless i'm missing something, your R1/R2 is the "mainline polarity management relay set", and is merely accepting alternating momentary inputs -- from whatever source. You're thinking 'cascade,' but I'm thinking 'modular'. This is why I suggested "mirroring" only your R3/4/5 set (my K3/4). Here is my interpretation:










From this exercise, it is seeming to me that your circuit involves two primary relay groupings: loop polarity management, and mainline polarity management. Your "LPM" (if you will permit me) further decides which reed switch in that loop gets to trigger your (again, please permit me) "MPM" (your R1/2). In the above, we have two "LPM's", each deciding upon which of their reed switches perform the mainline reversal. Further (and I know you know this; I'm just talking to myself), the "MPM" can receive multiple inputs (e.g., a third reverse loop or wye).

Two questions: is this a fair assessment? Second, I don't see yet how this method works with multiple signal-triggers to the "MPM" from a given loop's reed switch. Put differently, if I use your "BASS" approach (which I really like, it's so simple), won't all those wheels keep your R1/R2 pair flipping one way and then the other, reversing the main line repeatedly? I hope not, I'm counting on this nice, elegant circuit to work, Bro! But please 'splain to me why that won't happen.

Thanks for your continued engagement of this issue,
Cliffy









First off, I really like how you've integrated the two sides at the "multiplexer." Good thinking and way to go. You reduce the relay count by two (3 if R1 is broken into two relays) and by two for every subsequent loop. This saves cost, adds to reliability, and reduces the current requirements.










But in this case, you will need to add a diode for each loop placed between K1P2 and K3 (one on each side). Otherwise, when one loop throws, it allows current to flow though K3P2 activating K3 and this will throw the other loop at the same time and when the train returns, the turnout won't be properly aligned with the current flow.

Regarding your second concern, you only get one pulse to the MPM. As soon as the reed switch/gap is activated triggering the MPM, K3 pulls down through K3P2 and latches though K3P1 disabling this reed switch/gap at K3P5 and returning control to the other that you've already long passed at the other end of the loop..., but will come to again on your return trip unless you toggle the system to reset the path.

As I said, you should be able to trigger your turnouts at K3P5 and they will trigger to the proper direction each time a wheel hits. It is no problem for LGB switches to trigger continuously and a few dozen short spurts should have no detremental effect on yours. In fact, it may have no effect at all if there is an internal limit switch. If this is a concern, and you have one, try triggring it to one side a few dozen times in succession and see if it get warm at all. I'll bet it would be fine.

Hope this helps.


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## kormsen (Oct 27, 2009)

gentlemen, i live in a third world country. 
the last "wonderfull LGB item" i bought new... was about 20 years ago!
but, beside trains, i got another hobby: "make do!" - achieve what you want with what you got.

at the left you see a costly LGB reed (old model) - below it the shameless copy made by kormsen kitchentable electronics.

at the lower left you see a switchmotor from junkyard distributions ltd.

at the right you can see the replacements for the LGB additional switch avaiayable at your local heap of antique videoplayers.

i must confess, that most components for the reed-switches were bought brandnew - at the radio shack just round the corner (the corner being 300 miles away from here...)

you can bet, that i don't know any ideas, but cheap ones.


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## CliffyJ (Apr 29, 2009)

Thanks for the quick reply Todd, the confirmation, and the corrections. I'm thrilled that it's all getting simpler and simpler. 
I'll be on it like a big dog this weekend, and hopefully (& finally!) put this cad drawing to bed! 
Talk to you in a couple days, and thanks again,
Cliffy


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## CliffyJ (Apr 29, 2009)

Just an update, since I promised I'd have something by now...

Three evening sessions later, and I still haven't gotten it all working on the schematic! 
The latest thing that's been biting me is that when I tied in the actual switch machine trigger inputs, it kept introducing "sneak circuits" that messed things up. After putting some diodes in, it seems to behave, but I'm still stepping thru the loco positions and component states. 

Sheesh, this has been quite the humbling experience for someone who imagined he knew relays!  
To wax philosophic for a moment, this all reminds me of when I worked with HO scale as a teenager, about 35 years ago; I learned all sorts of electrical stuff. In a very real sense then, model railroading is once again my teacher for new things technical. And it's wonderful.

It's just that the gray cells nowadays are either less numerous or less agile. Probably both!









Cliffy


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 10 Nov 2010 03:49 PM 
Just an update, since I promised I'd have something by now...

Three evening sessions later, and I still haven't gotten it all working on the schematic! 
The latest thing that's been biting me is that when I tied in the actual switch machine trigger inputs, it kept introducing "sneak circuits" that messed things up. After putting some diodes in, it seems to behave, but I'm still stepping thru the loco positions and component states. 


Cliffy 


It would be nice to see what's actually going on electrically within the turnout. I've never seen those before and I imagine that between the triggers and lighting circuits, there could be some interplay. 

Have you tried it without the turnouts connected just to see if the relays are doing what they seem like they should be doing? Maybe leave the 12 volts off the turnout and the lights disconnected and replace the triggers with 12 volt bulbs (other leg to -) to see if they pulse on cue and if the relays properly latch as expected.


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## CliffyJ (Apr 29, 2009)

I admit that thus far, I'm only working the thing 'on paper,' Todd. You may well be right. According to the Train Li diagram though, the utility circuit internal to the switch machine (which I'm using for indicators) is a simple, independant SPDT.

Here's a question for you, though, referring back to your original diagram. Scenario is that all relays are relaxed; + is on the lower rail, train moving towards the loop. Operator flips the toggle up, intending the train to go counterclockwise. Turnout flips to the right, loop reverses polarity. However, the toggle signal (+6v) goes thru R4P1 and R3P2, and apparently activates the mainline polarity reversal -- which one wouldn't want to happen, correct? 

What am I missing, today?









Thanks again, and hope your layout activities went well last weekend,

Cliffy


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## toddalin (Jan 4, 2008)

Good catch. In my original drawing then the turnout is toggled, R4 toggles breaking the connection at P1, but there is a very brief instant when current may flow before the armature lifts. In my drawing I don't have the turnouts tied in at R3P2, so it wasn't an issue.

I think that we can fix this with a couple diodes. Normally the current flows from the armature of R4 to one of the poles. In this case, it would flow from the pole to the armature in the other direction. So it may be a simple matter of adding a diode to ensure that this doesn't happen.

Let's both take a look, give it some thought, see what we come up with, and compare notes.


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## CliffyJ (Apr 29, 2009)

Boy, you're quick.
Stepping back, and talking to myself again, the turnout toggle needs to reverse loop polarity (vs mainline) and ensure turnout throw, but not mess with mainline polarity. The "permitted" (via R3P2) RS's need to also throw the turnout (in my application), reverse mainline polarity, but at the same time double-reverse the loop polarity. 
It may be then that a diode between your R3P2 and (pointing toward) R4P1 might fix it.


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## toddalin (Jan 4, 2008)

Posted By CliffyJ on 11 Nov 2010 03:03 PM 

It may be then that a diode between your R3P2 and (pointing toward) R4P1 might fix it. 




That would seem to be the spot to do it.


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## CliffyJ (Apr 29, 2009)

That's great Todd, I'm glad for the confirmation.

Here's where I'm at with my schematic to this point:











Unfortunately, it's all so lo-res; how does one "post" a hi-res file on this forum? 

Also, I'm trying to work thru a time-based set of diagrams, showing what portions of circuitry are being energized for a particular step of the locomotive and relay state. I'd like to do a semi-animated Powerpoint, and co-author it with you, Todd. But I've no clue as to method of posting. Any ideas?

Cliffy


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## toddalin (Jan 4, 2008)

Looks good!

I don't think this site allows high res because of bandwidth and the need to serve all people. But you can link to a high res shot with the link icon. As for an action shot, you may need to go through YouTube. There are far more knowledgable people on that stuff than me.


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