# Switching riddle.



## Big_Steve (Feb 21, 2016)

I'm using Kato unitrack, N Gauge. I would like to run an inner and outer loop of trains going in opposite directions. But I would also like to be able to switch the two loops together to make one longer run. I figured to use one controller.


Will the switch always pass electricity, or only when switched? Obviously, I don't want it to electrically connect both loops.

The polarity reversal is easy to do from when the setup is turned off. I'll just use a rotary switch or relay. But can it be done on the fly?


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## Bwells (Mar 30, 2014)

Good riddle! More of a puzzle though. I assume you are using DC and the two loops are wired opposite from each other or do you have a reversing switch in there. Do you have a double crossover or two single crossovers? I am sure it can be done with a lot of insulators and switches. Could you post a drawing of the track plan?


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## Big_Steve (Feb 21, 2016)

I'm still in the planning stages. Just picture two loops with no common electrical connection, although they will share one controller. No switches yet.



Bwells said:


> Good riddle! More of a puzzle though. I assume you are using DC and the two loops are wired opposite from each other or do you have a reversing switch in there. Do you have a double crossover or two single crossovers? I am sure it can be done with a lot of insulators and switches. Could you post a drawing of the track plan?


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## MtRR75 (Nov 27, 2013)

Something does not add up here.

"Just picture two loops.....No switches yet".
Do you mean no turnouts (=track switches)?

"But I would also like to be able to switch the two loops together to make one longer run"
You need turnouts in order to be able to do this.

That is why we need to see a track plan before we attack the electronic issues.


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## MtRR75 (Nov 27, 2013)

"But can it be done on the fly?"

If you have a moving loco on a track segment, and you reverse the polarity, the loco will suddenly start going in the opposite direction -- not good for the loco, and most likely cars in the train will derail.

If you have no train on a track segment, no problem to reverse its polarity.


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## Bwells (Mar 30, 2014)

Many will tell you to go DCC and your troubles are over. I'm old school I like complicated stuff. Here is a start to think about however I am not happy with it. I think it needs more blocks but at least we can visualize what needs to be done. Check it out but I have a feeling to do what you want to is going to be a constant switch throwing event.


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## Bwells (Mar 30, 2014)

I thought about this a little more and am convinced you need another controller and wire the track for Cab A and Cab B.


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## Big_Steve (Feb 21, 2016)

The electric I can handle with no problem. What I really need to know is if a switch electrically connects both tracks all the time, or only if it is in one position. 

I want to run two trains in opposite directions. No problem. I occasionally want to only run one train, but switch in both loops so the run is longer. If the switch always connects both tracks, I can't do it. The reverse polarities will smoke the controller. But if a switch only connects both tracks electrically in one state, than I can probably do it.


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## Bwells (Mar 30, 2014)

By switch, do you mean turnout? If so, which make?


Edit: I think I see what you are asking and I would say yes, the rails are always connected which is the reason for insulating rail joiners.


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## Cycleops (Dec 6, 2014)

I don't have any experience of using unitrack but I would think the turnouts are 'power routing'. In other words they only send current in the direction they are switched. Therefore if you are operating one loco on each loop using two controllers as long as the turnouts are set straight ahead each will be isolated.

It might be easier to understand each other if we called turnouts turnouts and reserved the term switches for devices that switch electricity.


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## Big_Steve (Feb 21, 2016)

Sorry about the lingo. Pretty new to the hobby. Yes, I mean turnouts. 

So, if I can figure out how to isolate the turnout leg that connects to the second branch, I suppose the train will coast over the tiny "dead" area that I insulate and continue on?

What's a better way?


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## MtRR75 (Nov 27, 2013)

Big_Steve said:


> Sorry about the lingo. Pretty new to the hobby. Yes, I mean turnouts.
> 
> So, if I can figure out how to isolate the turnout leg that connects to the second branch, I suppose the train will coast over the tiny "dead" area that I insulate and continue on?
> 
> What's a better way?


They sell insulated rail joiners just for this purpose.

A train will have no problem crossing that junction smoothly, as long as the polarity is the same on both sides of the junction. If the polarity is opposite, the train will stop dead in its tracks due to the short circuit.

Better quality transformers have an overload protection circuit that shuts down the power when it detects a short circuit. That will protect both the locomotive and the transformer from damage.


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## Big_Steve (Feb 21, 2016)

Thanks, that's what I needed to know. Sorry if my convoluted description caused confusion. I work in electricity, so using a relay to match the polarity when I throw the switch for the turnout won't be a problem.




MtRR75 said:


> They sell insulated rail joiners just for this purpose.
> 
> A train will have no problem crossing that junction smoothly, as long as the polarity is the same on both sides of the junction. If the polarity is opposite, the train will stop dead in its tracks due to the short circuit.
> 
> Better quality transformers have an overload protection circuit that shuts down the power when it detects a short circuit. That will protect both the locomotive and the transformer from damage.


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## MtRR75 (Nov 27, 2013)

One other confusing part of this discussion is that you desire to use one controller to run 2 trains simultaneously. This can be done, but the trains will probably run at different speeds (unless they are identical locos), and when you adjust your power, both will speed up and slow down at the same time.

Most modelers that want to run 2 trains simultaneously want separate control for the two trains, so that they can adjust or stop one without affecting the other.

This is not to say that your method is wrong -- just confusing to those of us used to doing it differently.

Rule #1 of model railroading. It is your railroad. You can do whatever you want.


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## DonR (Oct 18, 2012)

Steve

It really doesn't matter whether the turnout is power
routing or not. You should use insulated joiners between
the turnouts that connect both loops together. You also will
need track connections (observe polarity) to both
loops. Put the joiners in the rails where the
turnouts touch. Use them on only ONE turnout
in each crossover. There will be no dead spots that
way. Since you have only one power pack and if
you connect the ovals with matching polarity there
will be no likelyhood of a short when the locos span
the insulated joiners, unless you introduce a switch
into the circuit from the power pack in one oval for
the purpose of reversing the loco.

A better DC system would use a 2nd Power pack
to power the 2nd oval, but you would still need
the insulated joiners to separate the two ovals.


Don


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## Ml-toys (Dec 19, 2013)

Are you attempting to switch so both loops to run the same direction with 2 trains going in opposite directions at the same time or will this be with only one running on the longer layout ?


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## Big_Steve (Feb 21, 2016)

I want to run two trains in opposite directions. Once in awhile, I would remove the train on the outer loop and use turnouts to be able to use one train in and out of both loops. I've got a handle on it now. 



Ml-toys said:


> Are you attempting to switch so both loops to run the same direction with 2 trains going in opposite directions at the same time or will this be with only one running on the longer layout ?


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## Big_Steve (Feb 21, 2016)

Second controller is down the road. It's already cost me 4 times what I figured when I stuck my toe in the water a few months ago. But, that's the way it goes with most hobbies too.



MtRR75 said:


> One other confusing part of this discussion is that you desire to use one controller to run 2 trains simultaneously. This can be done, but the trains will probably run at different speeds (unless they are identical locos), and when you adjust your power, both will speed up and slow down at the same time.
> 
> Most modelers that want to run 2 trains simultaneously want separate control for the two trains, so that they can adjust or stop one without affecting the other.
> 
> ...


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## Bwells (Mar 30, 2014)

AH HA: that makes more sense now and a piece of cake to do. Glad you have it figured out.


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## Overkast (Jan 16, 2015)

I came into this thread expecting to see the first post start off with "Two locomotives roll into a bar..."


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## Big_Steve (Feb 21, 2016)

Here's what I have so far. Long-long way to go.


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## Bwells (Mar 30, 2014)

Nice. Looks like your crossovers will need to go on the lower left. What is that long rectangular white box on the facia?


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## Big_Steve (Feb 21, 2016)

Power strip with nothing plugged in.



Bwells said:


> Nice. Looks like your crossovers will need to go on the lower left. What is that long rectangular white box on the facia?


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## Big_Steve (Feb 21, 2016)

That would be a joke, not a riddle. A riddle would be "If one locomotive in a bar drinks 90 drinks in 90 minutes, and a second one drinks 90 drinks in an hour and a half, where is the conductor?"



Overkast said:


> I came into this thread expecting to see the first post start off with "Two locomotives roll into a bar..."


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## Overkast (Jan 16, 2015)

Big_Steve said:


> That would be a joke, not a riddle. A riddle would be "If one locomotive in a bar drinks 90 drinks in 90 minutes, and a second one drinks 90 drinks in an hour and a half, where is the conductor?"


Touché Big Steve, touché. :thumbsup:


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