I have a real conundrum in trying to work out how to wire up crossovers between two mainline tracks. Track L to R has opposite polarity to one R to L. I have both Peco insulfrog and Electrofrog turnouts available along with a MRC autoreverse module. The system is DCC.
It appears to me that you have wired your layout for dc operation and not dcc. With dc you reverse an engine by switching the polarity on the track. Dcc uses ac current and reversing an engine is done in the decoder. So in dcc both tracks should be wired the same. Now if you have a loop at the end you install a reverse circuit in the loop that senses a short and reverses the feed to the loop. If you then have a crossover as long as you switch both turnouts simultaneously it will work fine. You can do that by using one switch to change both turnouts at the same time or put insulated rail joiners between the turnouts.
+1 [Y]
Rich
A great resource for getting your head wrapped around DCC wiring is here: https://dccwiki.com/Wiring_Turnouts
But in a nutshell: The easiest way to wire mainline crossovers in DCC is to ensure that the stock rails of the turnouts are wired to the same output terminal from the DCC command station, either Rail A or Rail B or whatever your DCC system calls their outputs. It helps to avoid thinking about polarity in DCC, and instead think “near-rail/far-rail”, and make sure you’re always wiring the “near-rail” feeders to the Rail A buss wire, and the “far-rail” to the Rail B buss, or vice versa. If you do that, the stock rails of both R to L and L to R crossovers will then be wired to the proper buss wires. That’s step 1; step 2 depends on what type of turnout your are using.
One thing to watch for with Electofrog turnouts (not Peco’s Unifrog turnouts) is the need to use insulated rail joiners on the two frog rails at the diverging end of the turnout. Those are the two middle rails of the four coming out that end of the turnout. The reason being is that in Electrofrogs, those rails are all part of the frog, and as such their polarity will change based on which direction the turnout is thrown, and one of those directions would result in a short at the connection to the next piece of track. Unifrogs avoid this by putting a gap in these frog rails before the end of the turnout, so you can use a metal rail joiner like normal.
It’s been forever since I used an Insulfrog, but I believe you can just connect the diverging end like any piece of track with metal rail joiners. However, there is a risk of a short if the metal wheels of your locomotives or cars bridge between the two frog rails and guard rails at the end of the frog. There are work-arounds for that, though.
The last thing you might need to consider is whether or not to power the turnout’s frog.
With Insulfrogs, it o
are the two mainline tracks connected together at both ends with loops
… instead of reversing sections?
[quote user=“jkovacs5”]
A great resource for getting your head wrapped around DCC wiring is here: https://dccwiki.com/Wiring_Turnouts
But in a nutshell: The easiest way to wire mainline crossovers in DCC is to ensure that the stock rails of the turnouts are wired to the same output terminal from the DCC command station, either Rail A or Rail B or whatever your DCC system calls their outputs. It helps to avoid thinking about polarity in DCC, and instead think “near-rail/far-rail”, and make sure you’re always wiring the “near-rail” feeders to the Rail A buss wire, and the “far-rail” to the Rail B buss, or vice versa. If you do that, the stock rails of both R to L and L to R crossovers will then be wired to the proper buss wires. That’s step 1; step 2 depends on what type of turnout your are using.
One thing to watch for with Electofrog turnouts (not Peco’s Unifrog turnouts) is the need to use insulated rail joiners on the two frog rails at the diverging end of the turnout. Those are the two middle rails of the four coming out that end of the turnout. The reason being is that in Electrofrogs, those rails are all part of the frog, and as such their polarity will change based on which direction the turnout is thrown, and one of those directions would result in a short at the connection to the next piece of track. Unifrogs avoid this by putting a gap in these frog rails before the end of the turnout, so you can use a metal rail joiner like normal.
It’s been forever since I used an Insulfrog, but I believe you can just connect the diverging end like any piece of track with metal rail joiners. However, there is a risk of a short if the metal wheels of your locomotives or cars bridge between the two frog rails and guard rails at the end of the frog. Ther
Hello All,
[#welcome] to the forums.
The moderators will review your first few posts so there will be a delay in seeing them.
My pike is DCC and I have two crossovers back to back- -four Atlas Snap Switches.
As long as the polarity is constant; all the right rails are “+” (red) and all left rails are “-” (black), and there is no loop or wye you should have no problems.
The only reason I have insulated rail joiners on each end of the crossovers is separate power districts, not a polarity conflict.
Lower yellow section to lower red section:
The wye in the center- -and the accompanying spur- -is a separate power district with a reversing section powered with an NCE AR10 Auto Reverser with built-in circuit breaker, the other power districts are controlled with single EB1s.
Hope this helps.
My initial statement still holds calling for all tracks to be wired the same except the wye which you say has the reverse circuit.
if they are parallel tracks the easiest solution is to place a “reversing section” leading up to & including one of the turnouts of the crossover
it can be controlled either manually or with a auto-reverser.
NOTE: the section needs to be longer than your longest engine or consist that may use the crossover & double insulated at all three places as indicated
if using an auto reverser…it will do the work for you…
if controlling manually you would need a DPDT reversing electrical switch to control the section
the switch would stay in "normal " for constant running on the green. When crossing from green to blue, you would place the switch to “cross” once the loco consist is completely in the red section. once you have made the crossover…the switch can be placed back to “normal”
When crossing from blue to green… place the reversing section switch to “cross” before the train enters the crossing, once the engines are completely in the red section…place switch back to “normal” before they reach the green section
Hello All,
That’s how you wire for DC when you “run the tracks” not in DCC when you “run the trains”.
What do the arrows in your diagram represent?
dbduck, if what you are proposing is true in DCC, why does the crossover on my pike work without a reversing section?
The only difference between the OPs situation and my track diagram is there is a second crossover that is wired exactly the same on my pike- -not a reversing section.
Yes!
Hope this helps.
According to the OP, the two tracks are of opposite phasing so there would be a short circuit as the locomotive went through the crossover
because of that you need a reversing section
The arrows on the drawing just indicates that the two tracks are of opposite phasing
Hello All,
OK, I see what you are saying!
Thank you for the clarification.
So, then the question becomes why is the phasing opposite?
Is the OP describing the center of a dog bone?
A track plan would help us all.
Good point for any reversing section being a balloon track, wye, or center of a dogbone.
Hope this helps.
Yes, I believe that the two tracks that are parallel to each other, possibly that result of a dog bone
Hello All,
At this point, it’s pure speculation on our part.
More information from the OP would definitely help.
Hope this helps.
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