# Need help planning Auto Reverser install on N Scale coffee table layout



## johnfm3 (Sep 30, 2016)

So I am planning on helping my dad build a n scale coffee table layout.

I need some guidance planning the installation of auto reverser's. I have gone back an forth on a few different configurations. I will post them in following post.


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## johnfm3 (Sep 30, 2016)

In this option, I would install a single auto reverser for the section in RED.


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## johnfm3 (Sep 30, 2016)

This is the setup I am really thinking I should do. It will utilize 2 Auto Reverser's for the GREEN and RED sections.


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## johnfm3 (Sep 30, 2016)

johnfm3 said:


> This is the setup I am really thinking I should do. It will utilize 2 Auto Reverser's for the GREEN and RED sections.


I should clarify... 2 Auto Reverser's, one AR in each colored (RED/GREEN) section.


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## cid (Jul 3, 2014)

I can tell this is makin' me think real hard... I smell something burning.
The CROSSING is two isolated tracks... I think they need to be connected and tied to the AR.
And try using one reverser. It will flip the phase/polarity/waveform of the crossing tracks any time it senses a shorted gap.
That's my 0.02. Disclaimer I am not a DCC guru. I am a DC gurunt. And welcoming other opinions...
Edit: If you have a loco or consist longer than the crossing, it's a problem. Move the gaps closer to the turnouts. 😊

Are you running more than one train?


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## Mark VerMurlen (Aug 15, 2015)

At first glance, I would choose your first option. It may still be the best of the two options, but perhaps not. If you want to run long lighted trains that are longer than the "X" section, then I would look more at option 2, but with some modifications. First, the "white" non reversing sections are not useful because they are too short. You should make the outside straight sections part of the red zone. The crossover can go to either the red or green zone. Then notice that you really only need 1 reverser on either the red or green zone. Double check my thinking, but I think that will work.


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## johnfm3 (Sep 30, 2016)

Given this is a small coffee table layout of 30in by 60in, we wont have much in the way of long trains. Based on your suggestion as well as others, here is new idea. As long as the entire train can fit between the turnouts in the red section.

Can anyone tell me how long a train we can fit in the red section? The corners are 11in radius corners. We have a E9 UP loco and plan on running a few flat cars holding John Deer tractors, followed by a caboose. I doubt we will run a ABA set unless the additional BA loco's are dummys. So how many Cars and a caboose can fit roughly?


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## DonR (Oct 18, 2012)

John

Yes, you have the right idea...however, you would have a much longer
isolated section that could accomodate a longer train if you simply
'reverse' your plan...make the opposite loop your iso section with
insulated joiners in both rails of the straight and diverge of both of the
turnouts on the left end of your plan. Or, you could simply add
more straight sections to the right hand loop that you show in Red
taking them from the left loop thus keeping the same size layout.

You would power the isolated section with the output of your
reverse loop controller...it's input is your track bus.

The crossover would need no special consideration.

Don


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## cid (Jul 3, 2014)

About 55 inches in the red section. "Between the turnouts" 35 inches.
Yes, I think Don is right on. gaps at the ends of the red section, everything else is the green section. Crossing as is from the box.


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## cid (Jul 3, 2014)

About 4-7/8" per 60' flatcar, coupled.


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## johnfm3 (Sep 30, 2016)

Don, can you draw out what you mean? I can send you the RailModeler file if you wish.


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## DonR (Oct 18, 2012)

John

No drawing needed. Just take 2 of your straight track sections from the top and
also from the bottom of your left (white) loop and put them into the top and bottom of your
right (red) loop. It maintains your layout scheme and size, just simply lengthens the 'red'
end and shortens the 'white' end. Thus making the 'red' isolated section
long enough for longer trains. The insulated joiners would continue to be
where the 'red' meets the 'white' sections in your drawing.

Don


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## Mark VerMurlen (Aug 15, 2015)

I think he means to add a few more track sections to your red reverse section like this:








That gives you maximum train length.


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## johnfm3 (Sep 30, 2016)

Don, Mark, CID
I was under the impression that it was good practice to give an extra length of track from the normal track such as the 2 curves right off the cross over going into the red section.

As a modification of Don and Mark's explanation....
As a reminder.... White is normal power off controller. Red is Auto Reverser section.










Or how about this....


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## Mark VerMurlen (Aug 15, 2015)

I think at this point we’re splitting hairs. Any of these will work fine. You’re getting to a train length that will make it look like the engine is chasing its tail around the layout, which is something you probably don’t want. The last design I’d rule out since you can’t have a train so long that the engine and rear end of the train could overlap at the crossing. I still like my version in post #13 because it gives roughly equivalent max train lengths regardless of how the turnouts are thrown in the reversing section.


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## johnfm3 (Sep 30, 2016)

Mark VerMurlen said:


> ...The last design I’d rule out since you can’t have a train so long that the engine and rear end of the train could overlap at the crossing.


So it looks like the one above it is the one I will go with. Thanks.


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## cid (Jul 3, 2014)

Which type of reverser are you planning for, relay type (AR-1, PM42, etc.) or solid state type (PSX-AR, ARM-2, etc.)?


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## DonR (Oct 18, 2012)

John

I agree with the others, the top drawing is the best choice. The
lower one would be troublesome if you were running more than
one train. 

Don


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## cid (Jul 3, 2014)

I am seeing those two plans as electrically identical. 
I think that either side can be either main or reversing section, just depends where you put the feeds. 
The crossing tracks go with one side or the other, doesn't really matter which. Am I misguided?
Wouldn't be the first time... 😂 
Regardless of which side reverses, you can't run a train all the way thru either loop if its tail end interferes at the crossing. 🛑


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## DonR (Oct 18, 2012)

Yes, cid, you are right, either the 'white' or the 'red' could be the
'isolated' section fed by the reverse loop controller. 


Don


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## johnfm3 (Sep 30, 2016)

So I will be running DCC Specialties Auto Reverser & Circuit Breaker on one side of the layout, and DCC Specialties Circuit Breaker on the other side.


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## cid (Jul 3, 2014)

I think that's a real good way to go. A lot of folks have success with the relay types, but the solid state solution 
seems a lot more appropriate for switching the DCC digital signal. 
Sorry that I can't speak from experience, only what I have learned from several on-line reviews, videos, commentary.


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## DonR (Oct 18, 2012)

There is no need for any separate circuit breaker in the main track
circuit from your DCC controller. The controller has a built in
circuit breaker. Any DCC reverse loop controller will work for you.
Again no additional circuit breaker is needed. 

As a matter of
information...DCC circuit breakers are mainly used on very large
layouts when there is more than one operator controlling trains.
The layout is broken into sections. Thus if operator B has a 'mishap'
that shorts the XX section track, the breaker for XX section trips, but the remainder
of the layout continues powered and operators A and C can continue
their fun in sections AA thru whatever.

Don


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## gregc (Apr 25, 2015)

maybe this is a good layout to have plastic wheels on all the cars?


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## johnfm3 (Sep 30, 2016)

gregc said:


> maybe this is a good layout to have plastic wheels on all the cars?


I didnt even think about plastic wheels on the cars. Thats a great suggestion. Thank You.


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## cid (Jul 3, 2014)

I think one of the main reasons to fit your entire train into the reversing section is so you don't have to worry about these momentary shorts. 
Personally speaking, I would not change all my wheels to accommodate this, but try to find a different method to eliminate shorts. (IMO 🙃)
I'm a fan of the steel wheels anyway...


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## Mark VerMurlen (Aug 15, 2015)

I’m a fan of steel wheels too. I converted all my cars to steel wheels years ago. They have worked very well.

Your main physical train length limiter is the loop to the right side of the crossover. You can’t have the back of the train interfering with the engine at the crossover point, unless you’re never going to run a figure 8 pattern. That’s why I’d include every piece of track in the right side loop except the crossover in the reverse loop.


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## johnfm3 (Sep 30, 2016)

So after all this conversation, I believe I have come to the following conclusions.

The entire length of the train will fit in the isolation section. We had already planned on it very rarely it doing a figure 8 run. Most times it will be ran as a way to turn the train around so it can go both directions on the left loop (white). A majority of the isolation section will be under a mountain and not seen. At least thats the idea in our mind so far. So the town on the left side can have the perception of a bi directional train going thru it.

As far as plastic wheels, I really like that idea as a preventive measure.

And as long as there is no tech reasons not to have a circuit breaker on the white section of track, they are cheap enough to add. In most cases, added safety and security is always an added bonus.

Thanks for all the guidance. My father n law and I are starting this build this summer during his visit.


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## Lemonhawk (Sep 24, 2013)

Try everything else before resorting to plastic wheels. They may seem like a solution, but just may cause a more annoying agravation.


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## johnfm3 (Sep 30, 2016)

Lemonhawk said:


> Try everything else before resorting to plastic wheels. They may seem like a solution, but just may cause a more annoying agravation.


Thanks for the heads up. I am sure I will bring up a discussion on this when the time comes.

Thank you everyone for investing the time in this to provide some guidance. I will send pictures as I start the work. Probably some time in July.

John


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