# Connections between loop-to-loop dogbones



## CliffyJ (Apr 29, 2009)

I admit it, this is a pretty obscure DCC question, but since it drives my future layout plans I'd like to understand the answers better.

My system is DCC, and I have a loop-to-loop layout, with both loops controlled by a DCC loop controller (i.e., the PSX-AR from DCC Specialties, with mod's to control my turnout switch machines). 

In the future, my plan is to added a second phase to the layout which will have a similar loop-to-loop approach. But that's a long ways off. Even so, I'd like to have layout plans that reflect best control practices, specifically, in connecting the track of these two loop-to-loop areas. 

Here are the three track connection methods I can think of. Red is main line, blue is a loop controlled by a PSX-AR. And, the focus of my question here, the green connection track.










I had been thinking that approach A, with the connecting leg being controlled by its own PSX-AR, would be "safest." But now I'm realizing that I don't have a firm grasp on the phase-shifting involved, and maybe the PSX isn't needed. But I don't know.

Approach A also requires a lot more track, and corresponding real estate.

I'd much rather use approach B, where the connecting track ties in on the reversing loops. This approach allows the loops to be a part of the "mainline" that, in real life, connected the two sections represented by the layout. 

Yes, if both areas are allowed to have trains running independently, any use of this crossover track has a serious potential of physical collision, which will have to be managed by operational means. For now, I'm just trying to get the DCC control implications. So, with approach B, and assuming the trackage of both the loops involved is completely clear of any other trains, how many PSX-AR's are involved? 1, 2 or 3? Is this a complexity that should simply be avoided at all costs, or an easy matter for the PSX-AR's to control?

Approach C is a variant, put up for the sake of completeness. 

[edit] Maybe my question can be distilled into the following diagram, maybe not. Picture a string of these along the main line, schematically. Here goes. 










Not sure if that oversimplifies things though. [end edit]

I'll be posting this question to DCC Specialties as well, and copy any reply here.

Thanks Greg, Dan and all others who can help me work through this.

Cliff


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## SD90WLMT (Feb 16, 2010)

B looks most practical and usefull..
.from a running and track work position....

Shortest tie between loops also..as presented..tho may not be in real life..


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## CliffyJ (Apr 29, 2009)

Dirk, I like what you point out, the "real life" thing. In real life, the main line went through everything I'd like to capture in the layout, though I'm slicing up the main line into portions that can be independently operated, in a loop-to-loop manner.

So, here's another diagram, reflecting what I may or may not be asking of the control system.










Red is main line (in real life). But numerous bumps along the way (more than are shown) might reverse the train or not. 

Cliff


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## Treeman (Jan 6, 2008)

Would the green segment in B,be long enough to fit your longest train?


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## CliffyJ (Apr 29, 2009)

Yes it would, Mike.


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## Greg Elmassian (Jan 3, 2008)

A needs no autoreverser
B - connect the green line to one of the 2 loops, don't add another autoreverser unless you will be having another train entering a loop while the train is transiting the green 
C - connect the green to the red, don't add another autoreverser.

basically if you tie the green to something that does not reverse, then you don't need anything extra... 

Greg


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## CliffyJ (Apr 29, 2009)

Greg, from what you said, I gather that any of these would work with just 4 autoreversers, except that B might need a fifth. 










Would you concur?

Thanks, it's making more sense to me now.
Cliff


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## Greg Elmassian (Jan 3, 2008)

yep, and if you don't ever intend to have a train in both ends of each loop at the same time, share an autoreverser with both ends of a dogbone if you want to save $$.

I would use the 4 separate reversers myself to keep wire lengths short, but then I use 10 gauge wire and 10 amp trains.

Greg


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## CliffyJ (Apr 29, 2009)

Cool!

My intent is to have one train running independently on each dogbone, for visitor times. So yeah, all four loops need a/r's. I'm glad though that I don't need an a/r on the leg connecting the dogbones. And when that connection is used, that's something I'm expecting to specially clear the route for. 

Thanks Greg,
Cliff


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