Wiring Turnouts

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Summary: Making turnouts compatible with your DCC system isn't hard. Here are ways to improve and modify commercial turnouts. Wiring turnouts for DCC sometimes requires extra care and attention.


Here are some recommendations for wiring turnouts on a DCC layout...

  • Feed track power to all routes in and out of the turnout.
  • Feed track power to all metal rails in the turnout.
  • Use live frog turnouts if possible.
  • Feed track power to live frog by mechanical or electronic switches
  • Use "DCC-ready" or "DCC-friendly turnouts" if possible.
  • If using PECO Electrofrogs, test metal rolling stock wheels for shorting between switch and stock rails. Consider modifying if problem occurs. Insulated rail joiners on the point rails[1] are required.
  • If using PECO Insulfrogs, test metal rolling stock wheels for shorting at the point rails.[2]
  • For more information on Shinohara turnouts, see the page for Shinohara


Wiring a Typical Turnout

This diagram shows where to feed track power to a typical turnout. Basically, feed power everywhere an arrow is shown and do not rely on the metal rail joiners, they don't always make reliable electrical joints.

In particular, try to feed power to all of the separate metal rail components in each turnout (except the guard rails). If two components are already electrically bonded with with internal wires (usually on the underside) then you only need to feed one of them.

Many turnouts (Peco is an exception) have the bonding wires already installed as shown between the stock rails and the closure rails. They might not be exactly as shown on the diagram (they can be on the other side of the frog for example) but if they're not there then ideally you should add them.

Finally, if the frog is live, wire up a frog feed from a frog polarity switch or a Frog Juicer.

PECO Turnouts

PECO turnouts cause a lot of confusion but fundamentally, all PECO turnouts can be used with DCC. There are a few reasons for the confusion. First, they come in two varieties, Insulfrog and Electrofrog. Second, even though PECO say they are "DCC-Ready", it can be argued that they are not "DCC-friendly". A third variety, the UniFrog, is beginning to appear. This new design will replace the Insulfrog and Electrofrog in time.

PECO Unifrog

Main article: PECO Unifrog

PECO has introduced their new Unifrog design, which combines the Insulfrog and the Electrofrog concepts into one. PECO intends to discontinue the Insulfrog and Electrofrog products over time, replacing them with the Unifrog design.

PECO Insulfrog Turnouts

Main article: PECO Insulfrog

PECO Insulfrog turnouts are power routing or self-isolating and therefore, it's not just good practice - one must wire all routes out of the turnout to avoid losing DCC power to a siding that is not selected.

PECO Electrofrog Turnouts

Main article: PECO Electrofrog

PECO Electrofrogs are simple to wire up for DCC, no special wiring is required. For more details, see the PECO Electrofrog article.

See Also

  1. The Point Rails in conjunction with the Wing Rails form the Frog.
  2. This is an issue often related to wheel sets lacking the recommended 3º taper. Insulated rail joiners on the point rails will eliminate this issue.