# Turnout Logic



## xrunner (Jul 29, 2011)

Thinking about how to wire up my turnouts. The outputs of my stationary decoders can operate more than one turnout at once. Looking at the picture of a siding as shown, we have turnouts A & B.

My thinking is that you could always operate the pair together, thus using only one output of the decoder and also simplifying operation since you keep track of only one turnout - not 2. Basically you call the whole siding closed or thrown. 

Both can be either closed or open together. This because whether you enter or leave the siding, there is no downside to having the other turnout in the same configuration. Same goes for the mainline, both turnouts have to be closed together.

It's kindof like the Kato double crossover. Even though crossing over involves only 2 turnouts, the double crossover always operates all 4 turnouts at once.

So in my current layout, I have 3 such sidings. Instead of keeping track of 6 turnouts, I would only keep track of 3 sidings. The siding (2 turnouts) is either closed or thrown. So far I can't see any downside to this logic.

Thoughts?


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## gunrunnerjohn (Nov 10, 2010)

I can visualize some contorted operations it might be a problem, but in general I think that's probably a good idea.


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## Xnats (Dec 5, 2010)

The only thing I see is that you would lose power on the main(between the turnouts) if using #6s but a power drop would fix that.


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## xrunner (Jul 29, 2011)

Xnats said:


> The only thing I see is that you would lose power on the main(between the turnouts) if using #6s but a power drop would fix that.


No, because I mod all my Kato #6 switches internally, like this -


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## Xnats (Dec 5, 2010)

I forgot about that thread. By the way that came out great :thumbsup:


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## xrunner (Jul 29, 2011)

gunrunnerjohn said:


> I can visualize some contorted operations it might be a problem, ...


Yes I know what you mean, but that won't be happening on my layout. A train will either be passing the siding or entering/leaving it. There won't be contorted operations going on.


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## xrunner (Jul 29, 2011)

Xnats said:


> I forgot about that thread. By the way that came out great :thumbsup:


I'm not sure why Kato doesn't change the way the #6 works. Seems once a device is made to work they don't want to touch the design. hwell:

I've got 20 turnouts in my layout and I've modded all but the last 4 which are on order. So far the mod has worked very well.


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## Reckers (Oct 11, 2009)

I've seen other layouts where that is the practice. It's a logical system as long as you time it correctly and don't derail another train that has to exit your shunted area before the exit turnout is thrown.


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## cv_acr (Oct 28, 2011)

I wouldn't. If you do, you cannot have trains arriving at both ends of the siding at the same time for a meet. (one taking the main, one pulling into the siding.)

This after all is the purpose of the passing siding.


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## xrunner (Jul 29, 2011)

cv_acr said:


> I wouldn't. If you do, you cannot have trains arriving at both ends of the siding at the same time for a meet. (one taking the main, one pulling into the siding.)
> 
> This after all is the purpose of the passing siding.


I don't understand why not.

You pull one train into the siding, switch it, and the other train goes merrily past it. The train on the main line can't go past the turnout that's thrown anyway until the other train pulls completely into the siding. :dunno:


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## sstlaure (Oct 12, 2010)

I can see what he's saying, sometimes the trains are coming into that junction at the same time, if you allowed for one end to be on the mainline while the other diverts to the siding, you could let train #1 take the siding while Train #2 continues down the mainline at a slow pace past the first siding turnout until Train #1 has cleared the main, if necessary it would stop just short of the last turnout, but if you timed it right it may not even need to stop.

I could definitely see wiring up my cross-over tracks in my yard in this manner as there will never be a time where both shouldn't be aligned.

There's no reason you couldn't wire it up as you stated, just realize that unless train #1 is completely on the siding, the second train can't occupy the track parallel to the siding.


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## cv_acr (Oct 28, 2011)

But while one train is pulling into the siding, the second train can arrive on the main and come all the way up to the switch that the first train is arriving at. Also, once both trains have arrived, the train on the main begins to depart, and the one in the siding can immediately begin to depart once the switch it needs to leave the siding is clear, even though the other train is still passing the other switch at the far end.

By throwing both switches at the same time, the second train must now hold itself before the beginning of the siding, and wait for the second train to completely pull in before the switches are reversed and it can pull forward alongside the first train. It then runs straight through and the first train must wait until it has completely passed the other switch at the far end before it can leave, when it should be able to go as soon as the second train clears the switch that it needs to depart.


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## gunrunnerjohn (Nov 10, 2010)

That was the _contorted operations_ I referred to. I was thinking the same thing, but it would be VERY un-prototypical to have two trains heading in opposite directions on the same track, so it depends on the level of realism you're looking for.


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## sstlaure (Oct 12, 2010)

exactly cv....wiring them separately will allow for smoother operations/passing.


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## cv_acr (Oct 28, 2011)

gunnerjohn: Um, that's not what I'd call "contorted operations". That's the most basic use case of a passing siding. The entire purpose of a passing siding is to allow two trains in opposite directions on the same track to meet or pass each other.

By throwing both switches at the same time, what should be a simple meet becomes akward because trains must wait for other trains to completely clear the switch at the opposite end of the siding before moving, and once the meet is made they can't leave at the same time.


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## xrunner (Jul 29, 2011)

cv_acr said:


> But while one train is pulling into the siding, the second train can arrive on the main and come all the way up to the switch that the first train is arriving at.


Thanks for explaining cv, but that kind of operation won't be happening on my layout. Even if it did, there is no reason that the mainline train can't wait at the far end of the siding until both turnouts are switched back. I just don't see it as a big deal, but thanks for your thoughts.


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## gunrunnerjohn (Nov 10, 2010)

Right cv_acr, I didn't think of that particular variation. In any case, all the facts are out. 

As we like to say here, it's your RR, you can do whatever you like on it.


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## Massey (Apr 16, 2011)

The whole point is the mainline train should not have to wait for the minor train to fully pull into the siding. Also what if the minor train is too long? You would need to preform a "Saw-By" and you need independant control of the switches for that to happen. I can see alot of problems with your trains splitting a switch with out indepentant control. Now for a cross over where you will not have opposing trains, you will ALWAYS need to have both switches flipped at the same time then yes I would say link them together. For a siding I say independant control.

Massey


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## xrunner (Jul 29, 2011)

I wasn't even thinking of using the sidings I have as passing sidings. I just envision them as delivery routes off the mail line for goods. That's why I don't see any problem with switching them both at once.

Even if I was going to use them as passing sidings, I don't understand why it's really a big deal in a model railroad, well at least mine. It's not as if a real industry is waiting by the clock for it's goods to be delivered. So, if one train has to wait for another to go completely into a siding, whether it's at the closest turnout or the farther one, what's the big deal? 

I mean I can see your point f you are running some kind of clockwork timing setup I suppose where nothing can afford any delays or such, but that isn't what I'm going to be doing.

But ... even if I want to change the way they work later, it's not a big deal. It's simply a matter of changing the wiring, and perhaps one more decoder.


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## sstlaure (Oct 12, 2010)

Definitely not a big deal xrunner and run your layout however you want to.

I think we're just advising on situations where you might want independent switch control if you hadn't previously thought about it.


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## NIMT (Jan 6, 2011)

I live right next to the BNSF main line and passing track. 
cv_acr did an excellent job of explaining normal operations. I have seen all the different passing scenarios but 90% of the time one is pulled off onto the passing siding and another goes thundering by and before that train even clears the switch the second starts rolling along. It takes some time to get them moving along again after a complete stop! 
The fun ones to watch are the rolling passes...rare but it's impressive to see two, mile+ long trains time a passing so that neither of them has to stop and no one gets a bent bumper!
Passing trains happen about 20 times a day here and It takes about 30 to 45 min for 2 trains to completely pass each other here, Models only take a few seconds.
In the model world we don't have 2 mile long sidings (I'm working on mine being close) for our trains to negotiate so the operations that xrunner has suggested will work quite fine!
Besides: #1 rule it's your RR do what YOU want!


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## sstlaure (Oct 12, 2010)

My thought is that in a model RR, you'd want to maximize the run that engines could move before they had to be stopped for a pass.


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## NIMT (Jan 6, 2011)

I would have to second that Scott, that's why I'm a dual main line fan! If you've got the room you just can't beat it for all out train running!


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## xrunner (Jul 29, 2011)

cv_acr said:


> By throwing both switches at the same time, what should be a simple meet becomes akward because trains must wait for other trains to completely clear the switch at the opposite end of the siding before moving, and once the meet is made they can't leave at the same time.


Well, I was thinking about this again today (I know, you thought you smelled smoke right?) and I realized that I believe I can have the best of both worlds. That is, I realized that I can duplicate wiring two turnouts to operate at the same time by using the route setup in the DCS100.

I can then switch either one individually, or by using a route, operate them both at once. Cool.


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## NIMT (Jan 6, 2011)

Now your stinking...Oh thinking!:laugh::laugh::laugh:


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## xrunner (Jul 29, 2011)

NIMT said:


> Now your stinking...Oh thinking!:laugh::laugh::laugh:


I'm learnin'


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## NIMT (Jan 6, 2011)

It never stops in the train biz!


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