Electrofrogs: To cut, or not to cut? That is the question

266 Views 10 Replies 4 Participants Last post by mj9, 11 d ago

mj9

Discussion Starter · 12 d ago

Peco points. Code 55. Electrofrog.

Seeing a lot of mixed/conflicting info out there when it comes to isolating the frog area.

For starters, the OO versions of the same points appear to come with closure rails already cut and bridging wires that can be snipped. That strongly suggests that having a cut in rails is generally the way to go.

A plethora of videos back this up for OO, with all manner of instruments being used to immediately destroy those bridging wires.

But the N versions of those same points do not come with rails cut or bridging wires.

And it quickly gets murky from there for N:

Many videos show the tiny rails being cut, a la OO. Mostly with Dremels wielded by individuals exhibiting varying degrees of glee, despite gouging chunks out of the stock rails in the process.
In contrast, DCC Concepts in this OO-based help doc (page 2) drop the hint, "By the way - N scale Peco is designed slightly differently and I’m assured by modellers in N that the gaps & links aren’t needed due to these differences, so if you are in N, you may skip the “gapping/bonding” part. It’s up to you"
And then there are also some videos like this one, where no cutting of rails takes place and we're assured that only drop wires plus a frog wire need to be soldered for it to be job done.
But then of course there is also Unifrog, which to all intents and purposes seems to be an Electrofrog that's been properly cut.

So all of this rather leaves me wondering whether 'tis nobler in the mind to suffer the slings and arrows of outrageous cutting, or to take arms against a sea of snips...

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34C

· #2 · 12 d ago

I would suggest you determine for yourself whether the N gauge electrofrog point functions adequately as supplied, by a practical trial. The design is functionally the same as the OO electrofrog; whichever closure rail is in contact with the stock rail supplies current to the live crossing (frog), so the movement of the closure rails acts as the switch for the correct supply to the crossing.

mj9 said:
But then of course there is also Unifrog, which to all intents and purposes seems to be an Electrofrog that's been properly cut.

Actually as supplied it's functionally an 'insulfrog', but with an isolated (your 'properly cut') metal crossing (frog) instead of a plastic moulding ( perhaps better named as 'insul/electrofrog?'). But as has become apparent, Peco's 'Unifrog' design, which attempts to keep the unpowered crossing as short as possible, is as intolerant of the range of OO wheelsets that are 'out there' as the 'insulfrog' design was.

The insulfrog design limitation became very apparent on adoption of DCC, the two insulfrog points on my existing layout quickly showed evidence of shorts leading to spark erosion of the diverging rail heads at the crossing: out they came, replaced by electrofrog equivalents, trouble eliminated.

Peco find themselves between a rock and a hard place in designing OO points because there is no accepted wheel standard, so what is (and in the past has been) supplied in RTR and kit OO models varies from a decent approximation to RP25 profile which will work reliably, to 'it's a wheel'. I imagine from my limited past experience that much the same is true of RTR N...

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mj9

Discussion Starter · #3 · 12 d ago

34C said:
I would suggest you determine for yourself whether the N gauge electrofrog point functions adequately as supplied, by a practical trial.

Thank you. A trial would certainly be an option, but it would seem like quite an involved and time-consuming endeavour to establish reliability issues when running with both cut and uncut points. I mean I'm sure that fundamentally they must both work. So I'm hoping to be able to count on the experience of those who have almost certainly already been here.

At a guess, I'd hazard that the cut versions might be better at avoiding shorts from derailments/bridging wheels. But some of the info suggests that might not be worth worring about in N.

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Nigel2001

· #4 · 12 d ago

Staying with the N Code 55 turnout.

As designed, Peco intend power to transfer to frog via the blades contacting stock rails. This is usually reliable until people start ballasting or painting rails, and then introduce "gunge" which stops either the tie bar moving fully, or the blades connecting. If wheels have the correct back-to-back they shouldn't touch the open blade and cause a short.

If powering the frog via a wire (rather than from the blades), then, what are the consequences of blade and frog connection being different whilst the turnout is moved (and thus cause a temporary short circuit). For DC this doesn't usually matter, for DCC it is a short circuit and will shut down the DCC system.
The short circuit issue can be solved several ways, using a switch/relay which moves when the blade is "mid travel" is one approach (some servo controller motors can operate a relay in this way, some motors will do this (assuming installed carefully so tiebar is "mid travel" when motor is "mid travel"), or arranging a mechanical link which achieves it). For DCC there is an electronics solution in "frog juicers" (named after original company product, but now a generic term for device) which swap the frog polarity automatically.

Or, the short is solved by modifying the turnout - cutting two rails. But, as noted, to do this neatly requires some thought/skill (and not a Dremel with a grinding disc!). If inclined to cut I'd use a piercing saw with a fine blade, which requires cutting them on the bench, not on a layout. If cutting the rails, may as well also electrically bond the blades to their stock-rails as that will remove any contact issues at the blades.

My solution - there are other ways to achieve N gauge track.

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mj9

Discussion Starter · #5 · 12 d ago

Nigel2001 said:
...The short circuit issue can be solved several ways, using a switch/relay which moves when the blade is "mid travel" is one approach (some servo controller motors can operate a relay in this way, some motors will do this (assuming installed carefully so tiebar is "mid travel" when motor is "mid travel"), or arranging a mechanical link which achieves it). For DCC there is an electronics solution in "frog juicers" (named after original company product, but now a generic term for device) which swap the frog polarity automatically.

Or, the short is solved by modifying the turnout - cutting two rails. But, as noted, to do this neatly requires some thought/skill (and not a Dremel with a grinding disc!). If inclined to cut I'd use a piercing saw with a fine blade, which requires cutting them on the bench, not on a layout. If cutting the rails, may as well also electrically bond the blades to their stock-rails as that will remove any contact issues at the blades.

Indeed, thank you. I forgot and should have added that I intend to use Cobalts to do the switching. Good to know though that Dremels arent really the way, should cutting be the "best" answer.

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Nigel2001

· #6 · 12 d ago

mj9 said:
Indeed, thank you. I forgot and should have added that I intend to use Cobalts to do the switching. Good to know though that Dremels arent really the way, should cutting be the "best" answer.

Cobalts introduce yet another issue - depends on which Cobalt, and which connector you select.....

There is the analogue Cobalt, which is just fine. Connect the switch contacts.

There is the digital Cobalt. Therein lies an issue. To make things "simple" (or keep costs down), DCC Concepts fit a "frog" output. That's connected to the DCC input to the Cobalt Digital.
But, if you get a short on the layout, you can no longer operate the turnout because the DCC will be dead.
To fix this, many people would advocate using an "Accessory Bus" and arranging cut-out devices so the main track feed is cut-off, but the Accessory Bus still works. This is good practice. BUT, the previously mentioned "frog" output would now be connecting the Track to the Accessory Bus, which defeats the whole point of separating them!
So, solution is to use the other full switch contact set on the digital Cobalt, and thus there is only one really usable contact set on that device.

- Nigel

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mj9

Discussion Starter · #7 · 12 d ago

[QUOTE="Nigel2001, post: 662057, member:
So, solution is to use the other full switch contact set on the digital Cobalt, and thus there is only one really usable contact set on that device.
[/QUOTE]
Gah! It is the Digitals that I have. But this answer has left me a little more confused than before. Likely I need to come back to it in the morning, when my head is a little clearer and I’ve had a chance to go over their installation instructions again.

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Nigel2001

· #8 · 12 d ago

Digital Cobalt have two switch outputs.

One labelled "frog", which has the problems I outlined. You could use it, and deal with short circuits as they happen, clear them, and it will then come back to life after the short is cleared. (*)

The other is a single pole change over (three terminals). Two inputs (one to each running rail on plain track) and one output (to the frog). If its the "wrong way", then swap the input connections over.

(* I recall seeing bizarre suggestions that a resistor is fitted in series with this feed to the frog. This would basically make the turnout a "mostly dead frog" turnout as the resistor won't carry enough current to power the loco. It is a bonkers suggestion. ).

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jamesed

· #9 · 11 d ago

First of all, if you can use Unifrog points rather than Electrofrog. That will save you having to fit insulated fishplates and they also come with a wire pre-fitted to the frog (which N gauge Electrofrog don't so you have to solder one on).

If you plan to use Cobalt IP Digital motors then it all becomes much easier. The frog switching changes over at the mid-point of travel so as long as you connect the wiring the right way around you will never get a short as a result of blade contact. There is no need to modify the wiring on either a Uniftog or Electrofrog point. They will work fine 'out of the box' apart from adding droppers and a frog wire feed where necessary.

My own layout is Code-55 with mostly Unifrog points which is wired this way and works without ever having any problems. My club layout is Code-80 with all Electrofrog points and similarly works perfectly.

Shorts only occur through user error trying to drive a train into a set of points set against the direction of travel. If that happens then the train will probably derail too so the system or section cutting out is a perfectly acceptable response. You can quite easily build in isolated sections into the V approaches to points using the S2 relay outputs of the Cobalt IP Digital, or better still switch in or out ABC sections to provide controlled slow and stop at a red signal. Prevention or avoidance of short curcuits is the best solution.

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mj9

Discussion Starter · #10 · 11 d ago

Nigel2001 said:
The other is a single pole change over (three terminals). Two inputs (one to each running rail on plain track) and one output (to the frog). If its the "wrong way", then swap the input connections over.

Thanks Nigel! Very helpful. Figured it was to do with the other connections on the Cobalt, and that's made it clear.

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mj9

Discussion Starter · #11 · 11 d ago

jamesed said:
First of all, if you can use Unifrog points rather than Electrofrog. That will save you having to fit insulated fishplates and they also come with a wire pre-fitted to the frog (which N gauge Electrofrog don't so you have to solder one on).

If you plan to use Cobalt IP Digital motors then it all becomes much easier. The frog switching changes over at the mid-point of travel so as long as you connect the wiring the right way around you will never get a short as a result of blade contact. There is no need to modify the wiring on either a Uniftog or Electrofrog point. They will work fine 'out of the box' apart from adding droppers and a frog wire feed where necessary.

My own layout is Code-55 with mostly Unifrog points which is wired this way and works without ever having any problems. My club layout is Code-80 with all Electrofrog points and similarly works perfectly.

Shorts only occur through user error trying to drive a train into a set of points set against the direction of travel. If that happens then the train will probably derail too so the system or section cutting out is a perfectly acceptable response. You can quite easily build in isolated sections into the V approaches to points using the S2 relay outputs of the Cobalt IP Digital, or better still switch in or out ABC sections to provide controlled slow and stop at a red signal. Prevention or avoidance of short curcuits is the best solution.

Exactly the sort of view I was after! And it's extremely reassuring. Thank you very much!

I've gone with Unifrogs where they were available (i.e. actually being manufactured) and Electrofrogs for the rest, which in my case has meant most of the points are Electrofrog. (Everything seems to take so long to come to market these days! Or maybe I've been away too long and it always did.) Anyway, if I'm being picky I prefer the look of the uncut rails on the N Electrofrogs, so at least in that one small regard it's a plus for me.

It's also been very helpful from this (and previous) replies, to have repeated in different words everything that's possible with the Cobalts, because things are actually starting to sink into my brain cell

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