What wiring is required for a wye for DCC?
Hello,
I have three reversing sections on my layout. Two are handled by the PSX-AR devices and one (the wye) is handled by a Digitrax AR1.
My setup is similar to the wye diagram presented here (scroll down)
https://dccwiki.com/Reverse_Sections
Good Luck, Ed
1arfarf3 What wiring is required for a wye for DCC?
In the following crude graphic that I constructed, I used the colors blue and red to illiustrate the two polarities of the wye.
As the two legs of the wye connect to the track, one side will always have mismatched polarities, as shown by the two green circles where blue meets red and red meets blue. I call that the "point of opposite polarity". That point must be gapped to avoid a dead short.
Thus, the wye becomes the reversing section. A reversing section must be completely isolated to make it work properly, so the other two pairs of circles (colored black) represent the other locations of the gaps. That pair of gaps on the tail of the wye must be set back far enough to allow the longest train to fit inside the reversing section.
Rich
Alton Junction
Hello All,
Gapping is key.
If you are using a stand-alone auto-reversing unit where you power the unit from matters too.
Best practice would be to power the AR directly from the bus wires.
I don't use a power bus, my pike uses terminal strips with track feeder wires radiating out from them.
Check out this thread...
Wiring a Wye for DCC
With my Bachmann Dynamis DCC system I used an MRC AD 520 auto-reversing unit.
You can find it much cheaper than the MSRP on their website, at other train retailers.
When I switched DCC systems to NCE I ran into problems when I added EB1s as outlined in this thread...
EB1 is not resetting
The best solution was to use the NCE AR10 which is an AR unit with a circuit breaker combined.
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
I should have given how I'm using the wye. Sorry.
The tail of the wye will be attached to the diverging leg of a switch. The two legs are sidings.
1arfarf3The tail of the wye will be attached to the diverging leg of a switch. The two legs are sidings.
In the following track plan, the yellow section in the center is a wye (not including the single siding). The green is what I believe you are describing- -minus the rerailing section that creates a switchback.
(Note: The different colors denote separate power districts and the track is isolated with plastic insulated rail joiners on both rails.)
That's not a wye, it's a siding.
Unless you want it to be a separate power district, no gapping is required and no AR unit is necessary.
Any section of track that is capable of reversing the direction of a loco is a reversing section and must be electrically isolated. That could be a loop, wye, or turntable. With a wye, one of the three legs must be isolated from the other two. There is no issue if you just have a wye turnout leading to two spur tracks. Such a track arrangement cannot cause the loco to change directions.
It's just a wye turnout to give me 2 spurs/sidings. Had read somewhere since original post that both rails leaving wye frog need to be isolated. Yes? No?
1arfarf3I should have given how I'm using the wye. Sorry. The tail of the wye will be attached to the diverging leg of a switch. The two legs are sidings.
1arfarf3 It's just a wye turnout to give me 2 spurs/sidings. Had read somewhere since original post that both rails leaving wye frog need to be isolated. Yes? No?
On my layout, I have a wye connecting to the divergent side of a turnout coming off the mainline. The two diverging legs of the wye feed into an 8-track passenger station. There are no gaps or isolated sections of track because none are needed. There is no point of opposite polarity.
1arfarf3It's just a wye turnout to give me 2 spurs/sidings.
a wye or a wye turnout?
greg - Philadelphia & Reading / Reading
What you have is a wye turnout to two dead end spurs. It does not create a reversing section. That is no different electrically than any other turnout. The key question is whether or not the frog is insulated. If it is insulated, no special wiring is required. If it is not insulated, the polarity of the frog has to be switched based on which route the point rails are set. Since these are both dead end spurs you don't have to isolate any rails. The entire length of the rails connecting to the frog can be switched with the frog.
There are several devices that will automatically switch the polarity of the frog and the rails leading away from it. Probably the most popular is the Tortoise which can be wired to the frog rails to set the polarity correctly when the point rails are switched. Another option is available if you use a Peco turnout machine. They sell an attachment which mechanically throws a switch at the bottom of the switch machine to change the polarity of the frog. A third option would be a manual switch but that would require you to throw that switch whenever you switch the point rails. If you are using a ground throw, that is probably your only option.
What brand of turnout do you have and do you use an electrical switch machine or a manual one (ground throw).
No.
A "wye" (equilateral) turnout is no different than any other turnout.
An actual wye (turning triangle) is a reversing section, and any track that allows a train to turn/engine around and go back facing the other way must be isolated and handled.
Chris van der Heide
My Algoma Central Railway Modeling Blog
Peco SL-E98 #8 wye turnout.
Walthers switch machines.
Will power the frog.
Wye turnout is a Peco SL-E98. #8.
1arfarf3 Peco SL-E98 #8 wye turnout. Walthers switch machines. Will power the frog.
I'm not familiar with either the turnout or the Walthers switch machine but assuming it is a non-insulated frog, you'll have to refer to the Walthers instructions for how to power the frog. The good news is that since both tracks are dead end spurs, you do not have to isolate the frog from the rails that join with it. That means the left hand rail on the right side spur and the right hand rail on the left hand spur can connect electrically to the frog. Those rails are just an extension of the frog.