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Using lights to show polarity on track blocks

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Posted by Ablebakercharlie on Monday, September 20, 2021 11:22 AM

7j43k

 

 

 

 

 

I certainly did not mean the tone of my questions to be "why on earth..."

I was, and am, curious at the reasons for choosing the system.  It's almost impossible to not run into the "standard" system of block wiring, as described in every model train electrical book that I can recall ever seeing.

And I was curious at the choice, and the reasons for the apparent rejection.

In an attempt to further grasp this system, I inquired about how running more than one train was done.  It now appears that both trains are run off of one throttle, and their speeds will increase and decrease together.  You have a system to choose alternate directions for each.

As noted by others, what you are doing is unusual.  And not at all obvious to someone who is just being introduced to it.

 

If you're happy with your system, I am happy for you.

 

Ed

 

 

Thanks for your response.   As with jjdamnit and Rich, I enjoy reading your posts too!

My mistake was thinking what I was doing was commonplace, hence my surprise when I was getting the responses I was getting.  

To me, it seemed very logical that if you are going to do DC and have stand alone block wiring,  why would you not want the ability to have multiple trains go in different directions at the same time.  

This method of course is not without its own problems.  It was noted by a poster that when a train crosses from one block into another it will temporarily energize that block even if it was switched off.  Very true and it is a bit of a bummer but I can live with it.  

Also when running two trains at the same time you will get different rates of speed usually.  Also not ideal but I can live with that too.

Regarding the polarity indication lights I might very well abandon the idea.  Once again, I am just starting the layout and am exploring, trying new things and developing new skills along the way.

I enjoy this forum as a fantastic resource for information and want to keep it drama free!

Thanks everyone.

 

charles

 

 

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Posted by CSX Robert on Monday, September 20, 2021 10:58 AM

The circuit posted by RR_Mel should do what you need and is probably the simplist circuit that wiill accomplish it.

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Posted by 7j43k on Monday, September 20, 2021 10:56 AM

Ablebakercharlie

However, I'm going to have to disagree with you about the responses to my post here being suggestions and advice.   From my viewpoint, most of them were along the lines of "you are doing it wrong" and "why on earth would you do it that way when everyone else is doing it another way".    Being put on the defensive trying to explain my decisions didn't seem very worthwhile to pursue. A lot of these threads have gone south and I didn't want to be part of the problem. I had a question, I posted it, got an answer that I think will work and that's it.

But in the spirit of not being offensive I'll give it another go.

I am a DC operator.  I decided to wire all the blocks as stand alone so there are no common wires  on the layout.  I have DPDT center off switches controling these blocks and I have one throttle powering all of them. 

I have one throttle and yes, I sometimes run two trains at once although not for any extended period of time.  An example - running a train around the mainline while running a train on a spur for a short distance. Not a big deal and I am certainly not claiming that one throttle can run a complex railroad.  Far from it.  

The idea of polarity indicator lights comes straight from p. 28 of my Andy Sperandeo's 1990 edition of Easy Model Railroad Wiring when he offers this technique as a visual solution to remembering to switch polarity on reverse loops.  I wanted to explore that technique on the whole layout as it is easy to forget the polarity of a block when there are so many.  Once again, a light is a nice visual cue instead of looking at the label on the switch.

Why the DPDT switches - remember, this is DC not DCC.  I want the ability to have trains be able to go in different directions on different blocks at the same time.  Also, with stand alone blocks,  if there is a wiring issue I can easily isolate the problem and address it.  Maybe a more experienced person wouldn't need this technique but for me I think it works nicely. 

 

I PMed jjdamnit because he seemed the like only one on this thread who was making an effort to see what I am trying to do.  And also I have found his posts to be very sensible.  Rich, I'll say I like your posts a lot too - they have been very helpful.

So once again, I apologize if my PM message was deemed offensive but then I found the tone of the reponses I was getting to this thread pretty off putting too.

charles

 

 

I certainly did not mean the tone of my questions to be "why on earth..."

I was, and am, curious at the reasons for choosing the system.  It's almost impossible to not run into the "standard" system of block wiring, as described in every model train electrical book that I can recall ever seeing.

And I was curious at the choice, and the reasons for the apparent rejection.

In an attempt to further grasp this system, I inquired about how running more than one train was done.  It now appears that both trains are run off of one throttle, and their speeds will increase and decrease together.  You have a system to choose alternate directions for each.

As noted by others, what you are doing is unusual.  And not at all obvious to someone who is just being introduced to it.

 

If you're happy with your system, I am happy for you.

 

Ed

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Posted by CSX Robert on Monday, September 20, 2021 10:44 AM

gregc

would you mind answering my question

 

 
gregc
if you don' thave two throttles, why wire them as reversing switches?

 

 

 

I believe he did: "I want the ability to have trains be able to go in different directions on different blocks at the same time."

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Posted by Ablebakercharlie on Monday, September 20, 2021 10:32 AM

Hello Greg,

Forgive me for asking but I'm not sure what "them" is referring to in your question.

 

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Posted by gregc on Monday, September 20, 2021 10:29 AM

would you mind answering my question

gregc
if you don' thave two throttles, why wire them as reversing switches?

 

greg - Philadelphia & Reading / Reading

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Posted by Ablebakercharlie on Monday, September 20, 2021 9:56 AM

Rich - No worries!  Thanks for your response.  

charles

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Posted by richhotrain on Monday, September 20, 2021 9:40 AM

Charles, thanks for that message.  I have to say, I was looking for a word other than "offensive".  I should have looked harder.  I have followed this thread with interest, but I have not contributed since I am not a DC guy. So, when I saw your PM comment, I was disappointed that a solution to your issue might not become public. I do understand how you felt about the nature of the responses that you were getting.

Rich

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Posted by Ablebakercharlie on Monday, September 20, 2021 9:32 AM

richhotrain
Unfortunately, this seems to be the latest development on the forum. An OP starts a thread, gets lots of replies filled with suggestions and advise, then resorts to a PM with one guy.

I'll first start by saying that I really like this forum and have learned a lot from the different topics discussed here.

However, I'm going to have to disagree with you about the responses to my post here being suggestions and advice.   From my viewpoint, most of them were along the lines of "you are doing it wrong" and "why on earth would you do it that way when everyone else is doing it another way".    Being put on the defensive trying to explain my decisions didn't seem very worthwhile to pursue. A lot of these threads have gone south and I didn't want to be part of the problem. I had a question, I posted it, got an answer that I think will work and that's it.

But in the spirit of not being offensive I'll give it another go.

I am a DC operator.  I decided to wire all the blocks as stand alone so there are no common wires  on the layout.  I have DPDT center off switches controling these blocks and I have one throttle powering all of them. 

I have one throttle and yes, I sometimes run two trains at once although not for any extended period of time.  An example - running a train around the mainline while running a train on a spur for a short distance. Not a big deal and I am certainly not claiming that one throttle can run a complex railroad.  Far from it.  

The idea of polarity indicator lights comes straight from p. 28 of my Andy Sperandeo's 1990 edition of Easy Model Railroad Wiring when he offers this technique as a visual solution to remembering to switch polarity on reverse loops.  I wanted to explore that technique on the whole layout as it is easy to forget the polarity of a block when there are so many.  Once again, a light is a nice visual cue instead of looking at the label on the switch.

Why the DPDT switches - remember, this is DC not DCC.  I want the ability to have trains be able to go in different directions on different blocks at the same time.  Also, with stand alone blocks,  if there is a wiring issue I can easily isolate the problem and address it.  Maybe a more experienced person wouldn't need this technique but for me I think it works nicely. 

 

I PMed jjdamnit because he seemed like only one on this thread who was making an effort to see what I am trying to do.  And also I have found his posts to be very sensible.  Rich, I'll say I like your posts a lot too - they have been very helpful.

So once again, I apologize if my PM message was deemed offensive but then I found the tone of the reponses I was getting to this thread pretty off putting too.

charles

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Posted by richhotrain on Monday, September 20, 2021 5:53 AM

gregc
 
Ablebakercharlie
Sent you a PM - jjdamnit 

i do hope jj will share the reason why able wired things as he did 

Unfortunately, this seems to be the latest development on the forum. An OP starts a thread, gets lots of replies filled with suggestions and advise, then resorts to a PM with one guy.

I can see announcing that a PM has been sent to another forum member if someone truly needs to communicate something of a private, personal nature. But, otherwise, it seems a bit offensive to just go silent on the forum.

So, hopefully, the OP or the other guy in this instance will come back to publicly discuss the OP's issue.

Rich

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Posted by gregc on Monday, September 20, 2021 4:24 AM

Ablebakercharlie
Sent you a PM - jjdamnit

i do hope jj will share the reason why able wired things as he did

greg - Philadelphia & Reading / Reading

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Posted by Ablebakercharlie on Sunday, September 19, 2021 5:04 PM

Sent you a PM - jjdamnit

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Posted by jjdamnit on Sunday, September 19, 2021 3:48 PM

Hello All,

I have been reading and re-reading the OPs posts.

7j43k
I don't understand why you wired this way. Could you please explain(?)
Is there a benefit over wiring the layout in the typical way most of the rest of us use?
You also reference "trains", in plural. But you also refer to "throttle" in the singular. I am not seeing how you run multiple trains on one throttle.

From my understanding of the OPs wiring and their comment...

Ablebakercharlie
Each block is wired to a DPDT center off switch so I can change the polarity or turn each block on or off. The throttle is for motion only.

It seems that they are not using "Common Rail" wiring.

They seem to have come up with a non-standard, Franken-bashed method of direction control based on a single cab, and DPDT center off switches, using the switches to control direction rather than the direction controller on the single cab.

When installing the Atlas Block Selectors the direction switch on the cabs are used.

If using the Atlas Controllers they do have direction switches built-in to them and the direction switches on the cabs are not use.

Perhaps this is where the OP got the idea of not using the direction switch on the cab.

dehusman
I have never seen a layout wired that way, also don't understand why you would want it that way, since it causes the very problem you are trying to solve which the "normal" method avoids.

Ablebakercharlie
When I am operating the trains and hitting all those DPDT switches like mad I sometimes forget what the polarity of a certain block is.

Using commercially available DC circuit controllers and block selectors, even if only using one cab for motion, would simplify the OPs delima.

dehusman
I guess I don't understand why its a problem, if the switches control the polarity, wouldn't the handle of the switch indicate(s) which polarity the track was assigned?
It seems sort of redundant to put a light over a switch to tell you which way the switch is thrown when the handle of the switch would indicate the same thing.

Every circuit I have worked with has a "logic" to it.

It seems the OPs "logic" has reached its inevitable dead-end with this circuit configuration.

The solution they are seeking is more complex than the problem they have created.

The OP might consider doing some research into "traditional" common-rail DC block wiring and utilize the Direction switch on the single cab rather than utilizing the DPDT C/O switch method currently in use.

If a DIY solution is sought by the OP then I suggest- -again- -the Complete Atlas Wiring Book, which shows schematics of their block controllers which can be replicated with DPDT C/O switches.

On the other hand, if I have misread the OPs posts/explanations, and they are using two (2) cabs then this...

Lastspikemike
...has nothing to do with polarity.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by gregc on Saturday, September 18, 2021 4:21 PM

Ablebakercharlie
Each block is wired to a DPDT center off switch so I can change the polarity or turn each block on or off.

shouldn't the switch select one of two throttles?

if you don' thave two throttles, why wire them as reversing switches?

greg - Philadelphia & Reading / Reading

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Posted by RR_Mel on Saturday, September 18, 2021 1:50 PM

I would suggest using a bridge rectifier, four Schottky diodes (1N5818). Voltage drop through a Schottky diode is about half of a regular diode.

Arrange the bridge between the two adjoining rails with the output going to an LED of your choice with this in series.


 http://www.hansenhobbies.com/products/lighting/electronics/led_cl_10/




I have two of these working on my layout at a wye and loop.  It works OK at 3 volts on DC and also on DCC.  I run dual mode, DC or DCC on my layout.
 

Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
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I'm beginning to realize that aging is not for wimps.

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Posted by Overmod on Saturday, September 18, 2021 12:18 PM

Ablebakercharlie
I looked for a bi-color LED where both colors are the same but could not find one.  Is there an LED with only one color but the current can travel in both directions and illuminate the LED?

I can't quite figure out how this addresses your situation, but I couldn't see the point of DC into a Wheatstone bridge either...

...so, to make one, you carefully file two packaged "LED"s down so that most of the package on one side is removed, and then cement them together (be sure they're opposite polarity as needed when joined).  Join or solder the leads or pads.  Then use clear epoxy or similar material to cast a lens around them if needed.

There have been posts here about reducing LED size to close to the actual device size (which is tiny even in older LEDs) for use in scale signal heads -- the 'community search' should find some.

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Posted by CSX Robert on Saturday, September 18, 2021 11:52 AM

Never mind - I missread some replies.

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Posted by gmpullman on Saturday, September 18, 2021 11:49 AM

Ablebakercharlie
When I am operating the trains and hitting all those DPDT switches like mad I sometimes forget what the polarity of a certain block is.

I'm in agreement with Greg here. Just why do you need a reversing switch on each block and not in the throttle?

Kalmbach Diagram

There's no reason to have reversing switches at 1, 2, 3, 4, or 5.

The big downside to "bridging" the gap on each rail is that whatever you bridge it with will allow some current to pass.

So if you have block 1 energized and block 2 turned off with your center-off switch, if there is a locomotive in block 2 it will be drawing current through your "lamp/diode" indicator.

A diode will allow "full" current (up to the rating of the diode) to pass in one direction which would negate any circuit interruption provided by your block switch.

If you have two diodes, "back-to-back" bridging the gap between blocks you negate the reason for having a gap in the first place.

Is your layout wired for common rail cab control?

https://www.trains.com/mrr/how-to/build-model-railroad/how-to-wire-a-layout-for-two-train-operation/

 

Good Luck, Ed

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Posted by dehusman on Saturday, September 18, 2021 11:46 AM

Ablebakercharlie
Each block is wired to a DPDT center off switch so I can change the polarity or turn each block on or off.    The throttle is for motion only.

I have never seen a layout wired that way, also don't understand why you would want it that way, since it causes the very problem you are trying to solve which the "normal" method avoids.

I guess I don't understand why its a problem, if the switches control the polarity, wouldn't the handle of the switch indicate which polarity the track was assigned?

It seems sort of redundant to put a light over a switch to tell you which way the switch is thrown when the handle of the switch would indicate the same thing.

Dave H. Painted side goes up. My website : wnbranch.com

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Posted by CSX Robert on Saturday, September 18, 2021 11:43 AM

Ablebakercharlie
That is an idea!   I have been just starting to play around with buck boosters as a prelude to do some lighting on the buildings on the layout.

A buck/boost converter should work.  One problem is you would have to feed it with DC of a known polarity so you would have to have a bridge rectifier circiut.  The bridge rectifier would drop the voltage about 1.2 volts, so the converter would have to turn on around 1.8 v.  It may be hard to find one that turns on that low but still handles the maximum voltage (there are buck/boost converters that don't have a polarity requirement, but that just means they have the rectifier on board and they will have a higher minimum input voltage to compensate).

 

The easiest circuit would just be a bridge rectifier feeding an LED, but again, you would have the 1.2 v drop, so the LED would have to turn on around 1.8 v.  Some red LEDs do have a 1.8v forward voltage, but you would also have a large enough resistor to protect it against the maximum voltage and once you add that it may not be visible at the lower end.

The best way I can think of off hand would be to use an optocoupler (actually a pair of them or a single AC input optocoupler to handle the unknown polarity) and separate power source to drive the LED.  The circuit gets a little more complicated, but it could turn on very bright at a low volatge and little variation in brightness throught the range.

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Posted by CSX Robert on Saturday, September 18, 2021 11:03 AM

York1

I guess I meant a diode bridge.  You can buy them for just a couple of dollars.

https://en.wikipedia.org/wiki/Diode_bridge

diode bridge is an arrangement of four diodes in a bridge circuit configuration that provides the same polarity of output for either polarity of input.

 

You were right the first time as well, a bridge rectifier is just a diode bridge in one package.

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Posted by 7j43k on Saturday, September 18, 2021 11:03 AM

Ablebakercharlie

 

 
gregc
isn't the polarity controlled by the throttle (except for reversing sections)?

 

Each block is wired to a DPDT center off switch so I can change the polarity or turn each block on or off.    The throttle is for motion only.

 When I am operating the trains and hitting all those DPDT switches like mad I sometimes forget what the polarity of a certain block is.  

  

 

I don't understand why you wired this way.  Could you please explain.

Is there a benefit over wiring the layout in the typical way most of the rest of us use?

 

You also reference "trains", in plural.  But you also refer to "throttle" in the singular. I am not seeing how you run multiple trains on one throttle.

 

Ed

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Posted by York1 on Saturday, September 18, 2021 10:56 AM

Overmod
York1
Would a bridge rectifier work with this?

What would you use it for?

 

The principal use of a bridge rectifier is to convert AC to full-wave DC, but everything he's doing is in DC already.  And his LED inherently incorporates a diode, although at restricted voltage, so four of them correctly oriented would give directly visible evidence of which diodes are forward-conducting.... 

 

Instead of alternating current, the setup would take DC current coming from either side and light the LED.

York1 John       

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Posted by York1 on Saturday, September 18, 2021 10:54 AM

I guess I meant a diode bridge.  You can buy them for just a couple of dollars.

https://en.wikipedia.org/wiki/Diode_bridge

diode bridge is an arrangement of four diodes in a bridge circuit configuration that provides the same polarity of output for either polarity of input.

York1 John       

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Posted by CSX Robert on Saturday, September 18, 2021 10:42 AM

Overmod
What would you use it for?

The principal use of a bridge rectifier is to convert AC to full-wave DC, but everything he's doing is in DC already.  And his LED inherently incorporates a diode, although at restricted voltage, so four of them correctly oriented would give directly visible evidence of which diodes are forward-conducting.... 

When you have DC of unknown polarity, a bridge rectifier gives you DC of a known specific polarity out.  To drive a single, non-bipolar, LED (he's already stated he only wants one light and one color) from power with unknown polarity, you'll need a rectifier in there somewhere.

The only problem with the rectifier is it will drop the volatge about 1.2 volts.

 

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Posted by Ablebakercharlie on Saturday, September 18, 2021 10:27 AM

gregc
isn't the polarity controlled by the throttle (except for reversing sections)?

Each block is wired to a DPDT center off switch so I can change the polarity or turn each block on or off.    The throttle is for motion only.

 When I am operating the trains and hitting all those DPDT switches like mad I sometimes forget what the polarity of a certain block is.  

 

  I am a visual person so if I have a light on my panel on the frontier between two blocks that can illuminate to tell me that I better change the polarity of the upcoming block or I'll get a short then I can keep the train merrily on its way.

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Posted by gregc on Saturday, September 18, 2021 10:10 AM

Ablebakercharlie
So when a train is in block A heading to block B and the light is on I know I need to change the polarity in block B.

isn't the polarity controlled by the throttle (except for reversing sections)?

if the same throttle is connected to both blocks, isn't rail-b connected to the same side of the throttle in both blocks?

or do you need a way to determine which throttle each block is connected to?

greg - Philadelphia & Reading / Reading

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Posted by Ablebakercharlie on Saturday, September 18, 2021 10:04 AM

Overmod
There are inexpensive buck/boost cards

 

That is an idea!   I have been just starting to play around with buck boosters as a prelude to do some lighting on the buildings on the layout.

 If I can give a nod to RR_Mel,  he has been super helpful giving me advice on lighting solutions based on the way he has his own layout wired.

I'm thinking a buckbooster set at 1.5 v and have it power a 1.5v incandescent then I wouldn't have to worry about blowing the incadescent and it would still be bright enough to see.

I am now wondering if I could wire it in such a way that one buck booster could drive multiple block wirings.   Possible?????

charles

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Posted by Overmod on Saturday, September 18, 2021 9:56 AM

York1
Would a bridge rectifier work with this?

What would you use it for?

The principal use of a bridge rectifier is to convert AC to full-wave DC, but everything he's doing is in DC already.  And his LED inherently incorporates a diode, although at restricted voltage, so four of them correctly oriented would give directly visible evidence of which diodes are forward-conducting.... 

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Posted by York1 on Saturday, September 18, 2021 9:41 AM

Would a bridge rectifier work with this?

York1 John       

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