PECO Unifrog

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Main article: Turnout
Unifrog detail.jpeg

Summary: The PECO UNIFROG is a new turnout design from PECO. Out of the package it will behave like the PECO Insulfrog turnout. PECO plans to replace their Electrofrog and Insulfrog products with the new Unifrog over time. Doing this allows PECO to eliminate two products and replace them with one. As of 2020 only a limited selection of Unifrog turnouts are available, but this is expected to expand with time.

There is additional information regarding turnouts in general on the Turnout page.


PECO Unifrog Announcement


From PECO:

The wiring of these new turnouts is a development of both the Insulfrog and Electrofrog designs.
For current users of the Electrofrog or Insulfrog versions of our turnouts the new Unifrog gives modellers the best of both worlds. As supplied, the turnout is wired completely “live”, except for the frog tip and wing rails, and can be used straight out of the packet without any further modification (and so behaves like an Insulfrog).
The stock rails are wired to the closure rails at the factory, which in turn are connected to the corresponding point rail. This means the turnout is completely live (except for the tip of the frog), no extra wiring required. If the turnout is being used as a switch to isolate a section of track then it is simple job to remove the wire that joins the closure rail and stock rail and it will work like a current Insulfrog. Peco provides a pair of pigtails to allow wiring the turnout to behave like an Electrofrog. (They have been spot welded onto the appropriate places.)
To change frog polarity the PL-13 or PL-15 change-over switch/microswitch, or the SmartSwitch SmartFrog PLS-130 with do the task. A Frog Juicer or a mechanical switch would also work.

PECO Turnouts

PECO manufactures a number of turnouts in various scales.

What is Unifrog?

With Electrofrog and Insulfrog, modellers were able to make good looking functional trackwork. The decision of Electro or Insulfrog had to be made at the time of purchase. After purchase, how you wire the Unifrog is up to you.

Unifrog Description

For ease of identification, the PECO part number has a U indicating Unifrog in the part number on the packaging. Example: ST-U750 is a Unifrog RH turnout, O Scale.

As shown in the picture above, the Unifrog has a metal frog, like the Electrofrog. The difference is that the Unifrog is constructed with gaps filled with plastic at the toe and heel, to isolate it from the rest of the turnout. Out of the package it will operate as a Insulfrog, except it is not power routing. Closer examination reveals the toe and heel of the frog are isolated from the track, so it will be dead when installed. There is a wire welded to the underside of the frog connecting the wing and point rails, allowing it to be powered using a microswitch or another device. This will allow the phase of the frog to be controlled with relation to the switch points, like the Electrofrog. As the frog is completely isolated from the trackwork, no additional gaps or insulated rail joiners will be required on the point rails. Gaps have already been incorporated into the design of the Unifrog.

If you flip the Unifrog over, you will see that there are wires connecting the closure rails to the appropriate stock rail, eliminating the potential of a short should a wheel bridge the gap between the switch and stock rails. Perfect for DCC operations. This also eliminates a failure point, as a mechanical connection using the switch rails isn't needed for power, like the Insulfrog.

The point rails are also connected to their matching stock rails by wires under the frog, like the Insulfrog. Unlike the Insulfrog, the position of the switch rails does not control power to the point rails.

Advantages of the Unifrog Design

  1. Ready for DCC out of the package
  2. No mechanical connections needed between switch and stock rails
  3. Dead or Live Frog operation
  4. Switch rails do not change phase depending on the frog's state
    1. Switch rails are not self-isolating. Both routes out of the turnout are powered, regardless of frog mode in use or position of the switch rails.
  5. The point rails are powered via wires beneath the turnout connecting the stock, closure and point rails.
  6. Insulated rail joiners not required on the point rails to prevent a short caused by power routing
    1. This feature is built into the Unifrog construction
  7. The frog is unpowered, unless wired via a switch (to control phase).
    1. Can be converted to Live or Dead frog without removal, by simply connecting or disconnecting the wire feeding the frog
  8. Only the stock rails need to be connected to the power bus

Disadvantages of the Unifrog Design

  1. The frog is dead unless powered
  2. No power routing as in the Insulfrog, should you want to run analog (DC), as the point rails are electrically connected to the stock rails

Possible mechanical short at the point rails if NMRA RP-25 wheels lack the recommended 3˚ taper. Wheel sets meeting the NEM standard do not exhibit this issue.

What is the Difference between Unifrog and Previous PECO Turnouts?

The revolutionary aspect of the Unifrog is that you can change your mind. Install them in them as they come (a dead frog as in the Insulfrog), then later decide to convert to a live frog (Electrofrog). With the Unifrog this can be done without having to buy new turnouts. In fact, you do not even have to lift the track to re-wire the turnout, providing a hole was drilled into the benchwork for the frog wire to pass through.

Unifrog Availability

Upcoming UNIFROG Releases
H0 70 #6 Right SL-U7061
#6 Left SL-U7062
#8 Right SL-U7081
#8 Left SL-U7082
83 #8 Right
#8 Left
N 55 Medium Radius
00/H0 75 SL-U1188 Right /SL-U1189 Left Bullhead Large Radius
H0 83 #6 Double Slip, North American
SL-U8364 #6 Diamond, North American
SL-U8362 #6 LH North American
SL-U8361 #6 RH North American
H0n3 70 Turnout
0 Setrack #2

Currently the PECO Unifrog turnouts are limited in selection. PECO has released an N Scale medium radius SL-U395F and SL-U396F turnouts, and for H0 the SL-U7061 and SL-U7062 #6 turnouts. For 00, they have released Bullhead rail products in the form of a Double Slip, Single Slip and Long Crossing. Also available is the SL-U8363 OO/H0 #6 Double Slip. The SL-U1188/1189 Large Radius C75 turnouts are also available. As tooling is replaced, more Unifrog turnouts will come on the market.

2020 Unifrog Product Additions

PECO plans for the following will be available during 2020, as shown in the table. There is also the possibility of a #8 in Code 70. PECO will also be reengineering their C83 #8 turnouts to the Unifrog format. Code 70 and North American C83 will also appear as they use the same track base dimensions. The global COVID-19 pandemic has interrupted most of these plans.

PECO has indicated the Code 70 #8 turnouts are almost ready for production.

PECO plans to introduce the Code 70 #6 SL-U7061 & SL-U7062 turnouts in Summer 2021, after the back orders for other Unifrog product has been filled. PECO has stated that demand in 2021 for their track product line is at an all-time high.

H0 / 00

PECO has announced that Streamline Code 70 #6 and possibly #8 turnouts, will be available soon.

PECO SL-U76/77 Streamline OO/HO Curved Turnout Small Radius Unifrog are delayed until 2022.

00 Bullhead

Bullhead turnouts in medium radius. PECO is also asking its customer base what they would like to see in the Streamline Bullhead series. Bullhead single slip, double slip, long crossing and medium radius turnouts will be delayed until PECO is in a better position to divert resources to these new items.

Wiring the PECO Unifrog

There are two options

  1. Install it directly from the package. The frog remains insulated from the closure and point rails and requires no extra wiring
  2. Use the pre-attached wire to connect the stock rails to the frog using an electrical switch

Unifrog: Wiring for Digital Command Control

Wiring the PECO Unifrog for Digital Command Control is not much different than wiring any other turnout

  1. Connect the appropriate stock rail to the appropriate wire on your power bus
  2. Power Routing of the Frog:
    1. Attach the supplied wire to a Frog Juicer, toggle switch, Tortoise motor or other device with can switch connections to the power bus
    2. If you don't plan on doing that right away, but may in the future, attaching a short length of wire to the pigtail provided may make life easier later
  3. Optional: For reliability, connecting the switch and closure rails with a small jumper (Competency at soldering is a must here)

Power Routing

The PECO Unifrog is not power routing.

From the factory, the point and closure rails are wired accordingly for proper operation. The switch rails are also powered, eliminating the need for a mechanical connection to power them. The closure rail is also wired to the adjacent stock rail. The frog is isolated from the closure and point rails. Therefore, insulated rail joiners are not required on the point rails.

Help Needed

Anyone who has purchased a Unifrog can take photographs to illustrate this article. It would be appreciated.


Many thanks to PECO for providing technical assistance for this article.

See Also


Demystifying the Unifrog

PECO Plans to gradually introduce Unifrog to all of its ranges of turnouts, in this video we explain what Unifrog is and what its benefits are.

PECO Streamline Code 83 Number 6 Turnouts Overview

A close look at the newly tooled number 6 code 83 Line Unifrog turnouts.