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Discussion Boards => HO => Topic started by: JimJim on September 29, 2014, 04:54:11 PM

Title: Wiring a Wye for DCC
Post by: JimJim on September 29, 2014, 04:54:11 PM
Hello All,
I’ve recently converted my pike from DC to DCC using the EZ Command system.
It is an oval with a stub Wye on one side of the oval inwards. A pretty simple Wye used for turning locos.
Both the turnouts from the main line and the Wye have insulated frogs.
I’ve used insulated rail joiners on all rails on both legs of the Wye just past the turnouts on the mainline.
The Wye is fed with a MRC AD520 reversing loop module drawing power from the main line, wired per the mfg. specs.
Here’s the problem:
When both sets of points are thrown to the Wye when a loco passes over the insulated rail joiners; one set of trucks on the on the mainline, on set of trucks on the Wye, a short occurs.
If I only throw the incoming set of points to the Wye, leaving the other set of points on the mainline, there are no problems. The loco then moves to the Wye, it is thrown in the other direction, the points on the mainline are reversed and away we go.
The position of the points on the Wye don’t affect operation. Once the loco is on the Wye the sequence of switching the points on the mainline doesn’t matter.
I have even been able to run one loco on the mainline loop while performing this opposed switching operation to turn another loco simultaneously!?!
This means that my switching actions need to be precise and I cannot have both sets of points from the mainline towards the Wye at the same time or the above described short occurs. Yet both sets of points can be switched to the mainline with no problems. The position of the Wye switch has no effect.
I’ve communicated this to MRC with not much success.
Does anyone have any suggestions on how I can wire this Wye so that both sets of points off the main line can be thrown simultaneously rather than sequentially?

Title: Re: Wiring a Wye for DCC
Post by: jward on September 29, 2014, 06:11:22 PM
try putting a gap in the mainline between the two switches. the gap should be on the same rail as the frogs of the mainline switches. 

this is how you wire the mainline part of a wye when using all rail or power routing switches, which is what i suspect you have. the resultaint short has absolutely noting to do with the autoreverse module, but is rather caused by the position of the points on the two switches setting up a short circuit on the mainline track.

Title: Re: Wiring a Wye for DCC
Post by: JimJim on September 29, 2014, 09:03:12 PM
I insulated the frog rail between the two Wye switches on the mainline; as you suggested, and moved the pickup points of the AD520 to the “outside” of the turnouts on the mainline of the Wye and it WORKS!!!
And, I still have independent cab control on the Wye and mainline operations with two separate consists! Exactly the solution I was seeking!!!
My test engineer, Earl, thanks you more. He was about to quit because of all the failed test runs.
I’ll post this solution in the other forums I’ve sought advice from and relay (excuse the pun) to MRC.
Thank you again!

Title: Re: Wiring a Wye for DCC
Post by: ALCO0001 on September 29, 2014, 11:45:54 PM
What type/brand of switches are you using?

Title: Re: Wiring a Wye for DCC
Post by: JimJim on September 30, 2014, 12:28:11 AM
The two mainline switches are PECO #2 Insulfrog and the Wye is an Atlas Mark IV Wye turnout. There are two sections of 15” Radius track from the diverging sides of the turnouts to the Wye on each leg.
The distance between the mainline turnouts is 20” actual; a 9” stock and two custom cut 5-1/2” pieces. The stub is a stock 9” section that can accommodate a single GP-40 at best. This is all Code 100 snap track.
Each turnout uses remote switches respective to their manufacturer powered by a separate 16V aftermarket transformer.
They are actuated through Atlas Switch Controllers. The two PECO’s are wired parallel through one switch controller; one switch throws both sets of points simultaneously. The Wye has a separate controller.
It’s a tight fit to say the least. If you have the room you could extend the stub to any length to accommodate your needs.
This is wired, as previously discussed, with an MRC Auto reverse module but an E-Z Command® DCC Automatic Reverse Loop Module could be used just as effectively.
It is all controlled with a Bachmann E-Z Command DCC controller with a “Blue Box” Bachmann analog controller attached; for DC operation, through a E-Z Command® 5 Amp Power Booster to provide enough power when running both DCC and DC consists.
Hope this helps.