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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.
PECO Unifrog Announcement
- 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 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.
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
- Ready for DCC out of the package
- No mechanical connections needed between switch and stock rails
- Dead or Live Frog operation
- Switch rails do not change phase depending on the frog's state
- 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.
- The point rails are powered via wires beneath the turnout connecting the stock, closure and point rails.
- Insulated rail joiners not required on the point rails to prevent a short caused by power routing
- This feature is built into the Unifrog construction
- The frog is unpowered, unless wired via a switch (to control phase).
- Can be converted to Live or Dead frog without removal, by simply connecting or disconnecting the wire feeding the frog
- Only the stock rails need to be connected to the power bus
Disadvantages of the Unifrog Design
- The frog is dead unless powered
- 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. PECO has made alterations to the Unifrog SL-U8361 and SL-U8362 #6, making the isolated segment of the frog longer, resulting in the point rails being further apart at the heel of the frog. A true rail wheel should have a tapered profile but there are many instances when the wheel profiles are in fact flat, which in some situations is enough to bridge the point rails at the heel of the frog.
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.
|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-U8361 #6 RH North American|
|SL-U8362 #6 LH North American|
|70||SL-U7061 #6 RH North American|
|SL-U7062 #6 LH North American|
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.
2020/2021 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 use the same track base dimensions. The global COVID-19 pandemic has interrupted most of these plans. PECO has also introduced the SL-115 PECO Streamline Transition Track, which incorporates sections of each type of rail to enable smooth transitions from one to the other.
PECO has indicated the Code 70 #8 turnouts are almost ready for production. 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.
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
- Install it directly from the package. The frog remains insulated from the closure and point rails and requires no extra wiring
- 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
- Connect the appropriate stock rail to the appropriate wire on your power bus
- Power Routing of the Frog:
- Attach the supplied wire to a Frog Juicer, toggle switch, Tortoise motor or other device with can switch connections to the power bus
- 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
- Optional: For reliability, connecting the switch and closure rails with a small jumper (Competency at soldering is a must here)
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.
By powering the frog using the factory installed pigtail, the Unifrog will act like anElectrofrog. The wire must be connected to a switch, either a toggle switch or the contacts on a switch machine, for proper control of the phasing during operation.
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. Share this page
- General Wiring Topics for DCC
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- Methods of Operating Turnouts
- DCC Friendly Turnout
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Demystifying the Unifrog
PECO Turnouts Overview
Complementing the PECO Streamline HO "83 Line" track system, the new and expanding "70 Line" system will be perfect for representing lightly-laid routes, short lines, freight yards, industrial spurs and also for modelling the early period of railroads. You might wish to use both systems side-by-side, for example, when replicating a heavily used modern mainline with a secondary route diverging away, or a feed to an industrial spur. To help modellers use both systems in this way we have also released the SL-115 PECO Streamline Transition Track, enabling the connection of our Code 83 and Code 70 systems with complete ease!