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Crossover in dogbone

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  • Member since
    April 2003
  • 305,205 posts
Crossover in dogbone
Posted by Anonymous on Wednesday, May 3, 2006 7:39 PM
I am constructing a layout configured as a dogbone (for my grandchildren). I have a crossover connecting the entry and exit to one of the loops. I am not sure how to arrange the wiring to avoid the short circuit. I am using Peco electrofrog turnouts with microswitches and am wiring for DCC operation. Non of the reference books I have found address this problem exactly. Any suggestions?
  • Member since
    May 2003
  • From: Santa Fe, NM
  • 1,169 posts
Posted by Adelie on Wednesday, May 3, 2006 8:34 PM
Welcome to the forum,

And you come out of the chute with a good question. Any crossover in a dogbone creates a reversing loop situation. I have several in my current track plan. The simplest way for DCC wiring is to isolate one of the two parallel tracks with the crossover turnout in the block. So both rails are insulated (gapped) in three places...before and after the crossover turnout and in the middle of the crossover rails. Wire that block through an autoreversing unit. When the locomotive takes the crossover and its wheels bridge the gap in the rails introducing a short, the autoreversing unit will reverse the polarity cycle of the block and match the polarity cycle of the two sides. When it exits the block and creates another short, the autoreverser will again reverse the phase of its block. The autoreverser reacts more quickly than the booster, so there will be no short cut-out and the locomotive will continue to humm along.

Keep in mind, autoreversing has predictable and undesireable effects on non DCC locos (they change directions).

If the plan is big enough/busy enough justifies it, you can wire the "northbound" and "southbound" tracks to different boosters, isolating them in the "bulbs" of the dogbone, and then set one of them to autoreverse. That will have the same effect on a larger scale, but the cost is the price of a booster vs. the $25 autoreversing unit. It is only worth it if there is a strategic or current load reason to have a second booster.

- Mark

  • Member since
    October 2005
  • From: California City
  • 199 posts
Posted by spectratone on Thursday, May 4, 2006 6:53 AM
try this site. look under dcc topics. very helpful.
http://www.loystoys.com/
good luck
glenn
  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Thursday, May 4, 2006 12:06 PM
Thank you for your quick replies. I know what to do now.

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