I have spent the last three hours trying to figure out how to be able to shut off track power using two switches, one on either side of the layout. I haven't had any luck! For all you electronic gurus out there, what type of switches do I need and how do I wire them?
I know how to wire twin switches for Tortoises but that circuit doesn't work because all the switches do is reverse the polarity. The power is always on.
Help!
Cheers!!
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
Dave, need a ittle better understanding of what you want to do? Do you use DCC or DC?
Sheldon
Hi Sheldon,
Here is the situation. I am building a free standing 5"4" x 12' layout using DCC. I have mobility issues so I want to be able to operate the entire layout from one side or the other. Let's refer to them as being the north side and the south side. In other words, I don't want to have to walk from one side of the layout to the other to get access to a control panel. To that end, there will be matching control panels on both the north side and the south side of the layout.
I want to be able to shut off power to several tracks, and I want to be able to shut the power off to each track from either the north side control panels or the south side panels. Therefore, I need to wire two toggle switches for each section of isolated track, and I have to do it so that either switch can turn the power off or on regardless of the position of the other switch.
I think I need something similar to the setup for using two toggle switches to control one Tortoise. I can post that diagram tomorrow. The difference will be that the Tortoise system keeps power on at all times and just reverses the polarity, whereas the power shutoff system has to be able to turn the power on or off from either switch.
Sorry if this explanation is a bit long.
Thanks for your help.
I hope the drawing makes sense.
You can do it with a pair of SPDT toggle switches.
With this arrangement, the position of the toggle does not indicate if the track is on or off.
If the track is on, changing either toggle turns it off, likewise, if the track is off, changing either toggle will turn it on.
-Kevin
Living the dream.
Hi Kevin,
I have a couple of questions.
What type of toggle switches are those, i.e. 'on-on'?
I assume that the orange box is the Command Station.
Thanks. I really appreciate your help!
Its is basically identical to a three way switch set up in a house. Say a 2 light in a hallway with a switch at each end. So to make it easy. A typical 3 way light switch will work just as well as a spdt switch. So the switch is an on off Type. Cause that is what the light switch is are. The orange box is your power source.
A pessimist sees a dark tunnel
An optimist sees the light at the end of the tunnel
A realist sees a frieght train
An engineer sees three idiots standing on the tracks stairing blankly in space
hon30critterWhat type of toggle switches are those, i.e. 'on-on'?
Yes, Single Pole Double Throw (SPDT) On-On switches.
hon30critterI assume that the orange box is the Command Station.
Well, like in all my drawings it is a Troller power pack, but your command station is wired in the same, so... yes.
NVSRRIts is basically identical to a three way switch set up in a house.
Yes, schematically it is exactly the same circuit.
NVSRRSo to make it easy. A typical 3 way light switch will work just as well as a spdt switch.
Yes, 3-Way light switches will work.
I do not like using household wiring control devices for model railroads. They are difficult to mount in a panel, and if you use the electrical box as a mount they take up a tremendous amount of space.
NVSRRThe switch is an on off type because that is what the light switches are.
Not really.
Household lighting control devices:
Single Pole: On-Off, SPST switch
3-Way: On-On SPDT switch
4-Way: On-On DPDT Reversing switch
Hi again Kevin and gang,
I want to have three LEDs in the circuit: one beside the isolated track and one beside each switch on the panels, and I want to have them display a red (off) - green (on) indication. Since the power to the isolated track will be shut off on occassion, inserting an LED into the power feed wire won't work. I could get an 'on' indication but the LED would not be lit with the track power off. If I use a DPDT switch, it would seem that I can set up a separate circuit through 1/2 of the switch strictly for providing +- power to the LEDs? Does that make sense?
Thanks,
Dave, are there other controls on these panels?
Why do you need a light to tell you something is off? I the indicator light is off, the power is off?
I can show how to do this in a more "refined" way, but it is not easily explained in works or even a real simple diagram (which I do not know how to quickly draw "electronically" and post).
I studied CADD to decades ago but ended up never using it. I forgot all that and never cared to learn any of the other "drawing" programs.
But if I understand a little better everything you want to do, I can draw a drawing and get it to you.
To do things similar to what you are asking I don't use toggle switches at all, I use lighted pushbuttons. And my controls can have as many multiple locations around the layout as you want.
Examples: All my turnouts are controlled locally and ona dispatchers panel. LED's in the pushbutton show the route selected, the postion of each individual turnout.
The buttons that assign throttles to bocks (I run DC) typically are at three locations, each end of the block and on the dispatchers panel.
When you push a button and change the status of a section of track, the LED indicators change at all the locations.
And becasue of how I do this it takes ver few wires out to the various locations.
Hi again Sheldon,
Thank you for taking an interest in my project.
Here is an example of one of the control panels as it currently sits. I'm still playing with the uncoupler locations. The working area of the panel will be 6" x 12" +-. The squares represent the size of the switch bodies and the circles are 3mm LEDs. Most of the LEDs will be bi-colour red/green. The uncoupler LEDs will be blue only.
The big question is why do I need redundant LEDs? The answer is simple. I can't remember which is the through route and which is the diverging route. Call me stupid if you will, but if I can't see which actual track the turnout is set for, I'm going to screw things up. Each turnout will have two bi-colour LEDs, one for each exit route. If the indication on one track is green then obviously that will be the route that the locomotive follows, and if the indication is red, either the locomotive is not going to take that route or more importantly, it will derail at the turnout if it is running against the red indicator.
I am going to do the same thing with the power shutoff tracks. If the LED is green then the track has power. If it is red, the track is dead. Redundant, yes, but it is also bullet proof, at least theoretically. I need bullet proof! I also want to put dwarf signals indicating the power status. Not prototypical but cool looking none the less.
The only exception will be the uncouplers. They will have a blue LED only to show when the uncoupler is set to work. The Rapido uncouplers have a blue LED that shines up between the ties directly over the uncoupler.
I appreciate your offer to show me how to simplify the wiring, but I feel quite strongly that it is more important for me to be able to understand the wiring based on what I know currently. I have enough to figure out as is without trying to learn new electrical theory. I have colour coded all the wiring, so if I am looking at yellow wire #T1-2, I know that wire runs from turnout switch #1 post #2 on the north panel to turnout switch #1 post #3 on the south panel. Yes, it will take a lot of wire but I'm pretty sure the layout won't collapse under the weight.
Please let me know what you think. You can even tell me what you think about me being a rather dumb electronic dinosaur!
hon30critterfigure out how to be able to shut off track power using two switches,
hon30critterI know that wire runs from turnout switch #1 post #2 on the north panel to turnout switch #1 post #3 on the south panel.
i thought you wanted to "power" a single track from 2 different switches.
now you're discussing controlling "turnouts" from different positions? if so, what type switch machines?
greg - Philadelphia & Reading / Reading
Hi Greg,
The original question was about how to turn power to a track off using two switches, each with a 'green=on', 'red=off' indicator. Sheldon asked me to explain why I needed to have an LED lit when the power is off. I was trying to explain the fact that my wee brain has trouble understanding things if they are not obvious. I get confused easily.
I raised the subject of turnout indications in an attempt to give an example of what I need to see in order for me to easily understand what is happening. Trying to remember which route is the through route is difficult for me. Things will be much clearer for me with one route showing red and the other showing green.
I apologise for going off topic but it was the only way I could think of to illustrate my mental challenges. I still have trouble telling right from left!
Sorry about the confusion.
hon30critterSince the power to the isolated track will be shut off on occassion, inserting an LED into the power feed wire won't work.
wouldn't it make sense that the track power LED is "on" when the track is powered? i don't see a need for an LED indicating track power is off
and i don't see how a DPDT switch helps, since the track can be powered with the switch in either position.
since the one switch connects directly to the track, a track power LED could be wired to that switch. it seems a separate wire is needed from track for the other switch panel
One thing that I haven't mentioned clearly is that I want to have dwarf signals showing red/green indications beside the tracks. I have some beautiful dwarf signals from Showcase Miniatures and it would be a sin to not make them useful.
I also do not want to use track power to run the LEDs. Don't ask me why.
hon30critterI want to have dwarf signals showing red/green indications beside the tracks.
the begging question is how many tracks?
it's not obvious that using DP switches in Kevin's (excellent) diagram is sufficient to provide power to either of 2 LEDs. some logic seems needed to one LED "on" when the other is "off"
(it's not obvious if DP switches can can route +/- voltage to control either of 2 LEDs wired in parallel with opposite polarity)
i think Sheldon might suggest using a relay with multiple contacts to not only provide track power but also use a DP contact to provide power for green/red LEDs on both panels as well as a dwarf signals.
another approach is to build a circuit that actually senses track power, regardless of the source. that logic mentioned above would also be needed to control 2 LEDs
but things are getting complicated
My thinking (dangerous, I know!) was that I could use a separate power source to provide + and - power to the LEDs through half of the DPDT switch using a separate power supply, not track power. I could tap into the Tortoise power for example. The other half of the switch would control the track power. Does that make sense?
The thought of getting into relays and power sensors worries me.
if there were a single dpdt switch, one pole could provide track power and the other pole provide + or - to a pair of LEDs.
but there are 2 switches wired in series. if the first switch selects either + or -, the 2nd switch has no option.
Hmmm. Thanks for pointing that out. I told you I didn't know anything about electronics!!
If I use 1/2 of a DPDT switch, can I wire two single colour LEDs to simply go on and off in rhe same manner as the track power does? I will not be able to use the dwarf signals the way I wanted but I can live with that.
Thanks for sharing your expertise.
Greg has pointed out that my desire to have bi-colour LED indications on the track power shut off switches is a somewhat complicated request. That means that I will have to live with a simple 'LED on, LED off' indication. Unfortunately, I can't figure out how to wire that up.
I have attached a version of Kevin's power shutoff diagram. Please enlighten me.
Dave, is this track a dead end spur?
Yes, all the tracks with power shut offs are dead end spurs.
Dave, your diagram shows the LEDs wired in series with track power instead of between some DC power source (tortoise power) and ground.
these would be DPDT switches where the one pole powers the track and the other pole powers the LEDs
if both LEDs are wired in series, only a single resistor is needed
So Dave, am I correct in understanding that all these tracks are dead end sidings and that their turnouts are all controlled with Tortoise switch machines?
How about an even simpler approach to this whole problem.
Am I correct in understanding there will be duplicate controls for these turnouts on each side of the layout?
If so, wire one of the power leads to the siding thru the contacts on the switch machine so that when the turnout is alligned against the siding the track power is off.
Modelers have been doing this in DC since model trains were invented.
Are your dwarf signals LED's? In any case they could be wired using the other set of contacts on the switch machine.
Just my opinion, but I think your control panels will be very cluttered and hard to read with all those switches and separate LED's in such a small space.
My other opinion, while the "three way" light switch wiring works, I do not like the idea that the switch position is not consistant with the "action".
I use circuits that use LED lighted pushbuttons, so a turnout simply has two pushbuttons and the selected route is lit up. And I can put duplicate buttons on as many different control panels as I want - 2 locations, or 20.
ATLANTIC CENTRALSo Dave, am I correct in understanding that all these tracks are dead end sidings and that their turnouts are all controlled with Tortoise switch machines?
Yes.
ATLANTIC CENTRALAm I correct in understanding there will be duplicate controls for these turnouts on each side of the layout?
ATLANTIC CENTRALIf so, wire one of the power leads to the siding thru the contacts on the switch machine so that when the turnout is alligned against the siding the track power is off.
Sheldon, thank you for offering such a simple solution! In fact, I can eliminate the power shutoff switches and indicators on the panels entirely and just look at the turnout LEDs to see whether the power is on or not.
ATLANTIC CENTRALJust my opinion, but I think your control panels will be very cluttered and hard to read with all those switches and separate LED's in such a small space.
I will know the answer to that question as soon as I build the first trial panel. I'm trying to keep them small because I will be sitting most of the time when running the layout. I don't want them protruding above the fascia and I don't want them hanging too far below the fascia either. I can stretch them lengthwise without having to make them taller if they are too crowded.
ATLANTIC CENTRALMy other opinion, while the "three way" light switch wiring works, I do not like the idea that the switch position is not consistant with the "action".
That is a compromise that I can accept. I will be focusing on the LEDs anyhow because that is how my brain works.
ATLANTIC CENTRALI use circuits that use LED lighted pushbuttons, so a turnout simply has two pushbuttons and the selected route is lit up. And I can put duplicate buttons on as many different control panels as I want - 2 locations, or 20.
I have already purchased all the toggle switches so I'm going to work with what I have.
Again, thanks for all the input! I can scratchbuild things easily but wiring makes my brain hurt.
I want to thank you again for all your help, but I think that Sheldon has come up with the perfect solution. I have included LEDs for signals in the Tortoise circuits so I can use the dwarf signals in a more prototypical manner. I don't know why I didn't see that before.
those contacts are really just rated to provide intermittent power. others have added micro-switches to the machines
the other thing is these are spurs in a ladder and both spurs from a switch may be off. of course you can wire the tortoise switches in series to only provide power to the select ladder track, but then one spur will always powered.
I just went back to my panel drawings and eliminated all the toggle switches and LEDs for the track power shutoffs. That is a total of 72 items that will not be on the panels (18 toggle switches plus 18 LEDs x 2 sets of panels = 72 fewer holes in my head holes in the control panels)! Thanks again Sheldon!!!
Kevin,
I can't forget about your help either. Thanks.
gregc ATLANTIC CENTRAL If so, wire one of the power leads to the siding thru the contacts on the switch machine so that when the turnout is alligned against the siding the track power is off. those contacts are really just rated to provide intermittent power. others have added micro-switches to the machines the other thing is these are spurs in a ladder and both spurs from a switch may be off. of course you can wire the tortoise switches in series to only provide power to the select ladder track, but then one spur will always powered.
ATLANTIC CENTRAL If so, wire one of the power leads to the siding thru the contacts on the switch machine so that when the turnout is alligned against the siding the track power is off.
Not according to the manufacturer. They specifically say they can be used for powering frogs and routing power.
I have never had a failure using them in those ways.
I think a few guys found a way to overload them and then it became like an urban myth that you could not use them for track power. I had a friend years ago that mounted all those extra switches, I never saw the need.
And somehow don't see Dave running 4 powered units pulling 50 cars and running that current thru the Tortoise contacts.
Looking at Dave's diagram above there is no problem with my plan. If the top turnout 12 is set to the ladder, and 14 and 16 are set thru to 9, all the dead end tracks will be dead. 12 will be the origin feed for 13 and 15, so that whole leg will only be powered when 12 is alligned in that direction.
Easy Peasy, like we have always done in DC.
Why doesn't he just get one humongous latching relay for each set of feeders he wants to energize, and then wire as many momentary-contact pushbuttons to it as he wants "power on-off buttons" for that section. Each time you press any button, it toggles the relay -- if it was on, it will turn off; if it is off, it will turn it on. Then just have one big power-on LED per section, perhaps in something like a CTC board that shows the track layout, where you can see it.