EXRail, Virtual Turnouts and Sequences

[PeterP]

Hi guys,
I'm just returning to MRR after at least 30 years, and I'm really interested in getting into DCC++.   I have started planning my layout, which contains a few reversing loops, and I'm trying to wrap my head around automating the reversal of track polarity.  I can find a little bit on EXRail automation, but very limited in the way of in-depth tutorials online, beyond the DCC++ pages.   I'm hoping someone can direct me to a good place to find information and examples. 

[Sumner]

Yout mention DCC++ a couple times.  Since you also mention Ex-rail are you going to be using DCC-EX?

If so I posted a question about this on the Discord Channel.... https://discord.com/invite/PuPnNMp8Qf .... but think I might know the answer so will give it a shot and report back when I hear back (you could also go to that link yourself).  The standard command station has two track output but can have up to 4 easily with the new ready-to-run CSB1 with their motorshield on top of it.  With the DIY command station you can have up to 8 track outputs (I'm building one of these now).

I believe that the reversing section needs one of the track outputs reserved for it.  If so with the basic command station you could have only one reversing section along with one track output for the rest of the layout.

If this is true then I'd probably (and what I'll do) use a commercial product like what Tam Valley and others sell to handle the reversing section and keep the track outputs you have available for larger blocks that could run DC or DCC locos on them.  They aren't that expensive.

It is going to depend though on your layout and the size and what you are doing.

Sumner

[peteski]

Not sure what you mean.
With DCC the polarity of the track signal doesn't make a difference. "From the decoder's view forward is always forward".  The only issue is with reversing loop. While the decoder doesn't care, the end of reversing loop will have the DCC track signal polarity flipped 180 degrees out of phase with the main linie.  You need a device which will automatically flip the polarity when the train crosses that segment to prevent a short.  There are several brands of DCC auto reverses available, and their operation is transparent. No DCC++ required.  Reversers are standalone devices.

Quick basic tutorial:  https://dccwiki.com/Auto_reverser

[Sumner]

Got an answer on Discord.  Any district you use the DCC-EX auto-reverser in is going to take up one track output and that section should probably be small as it is all going to reverse when needed and you wouldn't want two locos entering at the same time from different directions.  If you are a single operator you might get away with it being a larger district. 

If you have the basic command station with two outputs you could only have one auto-reverser section as you would need the other track output for the main.  If you have more motorshields you could have more reversing sections if you didn't need but one main. 

With the $40 8874 motorshield on the ready-to-run CSB1 command station you would get two more track outputs so you could have one main and three reversing sections.  Also any of those could be a temporary program section and a short program track could be attached to one with a DPDT switch to isolate the programming current to only the short section of track.  You can change back and forth between program and main or reversing section with your throttle.

Hope that all makes sense.

Sumner