# "Keep Alive" versus "make turnouts DCC freindly"



## george (Jun 18, 2013)

This may merely display my ignorance but: On the one hand, we read about the wisdom and techniques for preparing live frog turnouts (e.g., Peco, etc.) to be DCC friendly to both avoid shorts and, more importantly, to assure smooth (and continuous) running at slow (yard switching) speeds through the frog area. OK, got it. Now comes "Keep Alive" DCC decoders which store a sufficient reserve charge to carry the locomotive through these dead spot current interruptions. So (1) if we modify the turnouts as per option one, is "Keep Alive" an unnecessary complication & expense or (2) if we use "Keep Alive" should we forgo the turnout modifications and, indeed, stick with the far less complicated "insulfrog" versus "live frog" turnout system? What am I missing here?


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## Brakeman Jake (Mar 8, 2009)

You're not missing a thing...simply two solutions to the same problem.My opinion...I like the "keep alive" better as it doesn't apply to turnouts only.More costly...no,when you consider the hardware to power turnouts plus the hassle...well,your choice.

I never bothered powering a single frog yet.I run newer generation six axle locos and big steamers with plenty of wheels,so dead frogs I don't know.These will only be an issue with very short or older engines anyway.


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## DonR (Oct 18, 2012)

Best way around the frog problem...Peco INSULFROG turnouts. Never a problem
on my DCC layout. They do 'power route' tho. You must add drops
beyond each one to 'stay alive' on the track.

Don


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## cv_acr (Oct 28, 2011)

Actually, two very different things here. A "keep-alive" decoder is just more tolerant to short dead spots; it has nothing to do with "DCC friendly" turnouts per se.

A DCC system will shut itself down real fast to protect itself from shorts. To make sure a turnout is DCC-friendly is to make sure there aren't any places that can cause momentary shorts, like too-small insulating gaps on frogs that wheels can span across, or solid one-piece point assemblies (in selective "power-routing" turnouts that only provide a complete circuit on the route lined) where the backside of a wheel can cause a short between the stock rail and the point.

Dead frogs are totally DCC friendly as they won't cause any shorting. It just causes a slight dead spot which could cause either a DC or DCC locomotive to stall just as easily. The solution to a one-piece electrically isolated frog is to make it as short as possible, and if your locomotive picks up from all wheels (and generally only older cheap train set stuff doesn't have all-wheel pickup) they shouldn't notice. The other option is to power the frog, but you need to change the polarity depending on which route through the switch is being used. You can do this using relays or auxiliary contacts built into several types of switch machines. Of course if you run a switch the wrong way, you cause a short as soon as you hit the frog. Of course if the frog is dead, you most likely just derail when you run through the reversed points and then cause a short anyway.

However in DCC there are some neat electronic tricks for dealing with isolated frogs. A keep-alive decoder gives you a fraction of a second to pass over a dirty or dead spot. You can also get these little auto-reversing circuits called "Frog Juicers" to power frogs, that automatically flip the frog polarity when a train hits it.


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## DonR (Oct 18, 2012)

Cris

You are certainly right in all that you have stated...but even so, I can't
get my mind to wrap around the complications and extra expense
of those various circuits and devices when the Peco Insulfrog or even plain
old Atlas turnouts will provide a correct electrical path for most
any locomotive or lighted car.

On my DCC layout, I run only 4 axle diesels and one 2 powered axle doodlebug and just don't have any blinks or pauses on my Peco Insulfrogs. The Doodlebug seems to
have wider wheels that short where the rails converge in the frog but
a dab of clear nail polish eliminates that with no negative to the flow
of power to the locos.

Don


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## Southern (Nov 17, 2008)

I agree with DonR.

I have Atlas, Peco Insulfrog, 2 Peco Electrofrog, and one Shiahara double cross over. All work great. The electrofrog had to have insulator on the two outgoing frog rails. The cross over has all four turnout motors wired to the same switch.


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## cv_acr (Oct 28, 2011)

Most of the time dead frogs aren't an issue, unless you have particularly long frogs and little 4-wheel (not 4-axle) critters. If the frog is long enough, and the power truck short enough, you could have issues.

Most locomotives pick up from both trucks so even if one is dead, the other should be drawing power and provide uninterrupted operation.

So if you happen to use solid-frog turnouts, and you like little tiny switchers, or trackmobiles, there's a possbility of stalling on the frog if the switch has a particularly long frog.

I'm handlaying switches, so the frogs are one-piece (one soldered together into a unit) and gapped/isolated. But I run 4 and 6 axle locomotives (from GP7 to SD40-2) so most of the frogs are short enough that there's no issue.


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## 05Slowbalt (Dec 19, 2011)

Okay I am not a fast learner and I have a question here. I have all Peco Electrofrog switches. I need about 60 switches and have already bough 10 Peco Electrofrog (and there not cheap). I am running DCC. So is there something I have to do to stop them from shorting out? I am confused by the Electrofrog and Insulfrog. Is there one that is better then the other or more DCC friendly. I will be doing switch machines on the hard to reach or hidden ones and ground thorws on the rest (but over time will replace also not planing on doing Decoders on the switches). Thanks.


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## Southern (Nov 17, 2008)

05Slowbalt said:


> So is there something I have to do to stop them from shorting out?


Yes put an Insulated rail joiner on the two inside rails leaving the turn out.





05Slowbalt said:


> Is there one that is better then the other or more DCC friendly.


Yes, The insulfrog. but you do not need to get reed of the electrofrog ones.


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## 05Slowbalt (Dec 19, 2011)

Thanks Southern.


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## DonR (Oct 18, 2012)

05SLOWBALT

Strongly agree with Southern.

On additional buys switch to Peco's INSULFROG. But isolate the frog on the
Electrofrogs that you do have.

Peco Insulfrog turnouts use power routing. That means
that power will be cut off, for example, to the diverting track
when turnout is set to straight. You will have to add drops
to your diverting track and straight track rails that converge
at the frog. 

Don

Don


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## 05Slowbalt (Dec 19, 2011)

DonR said:


> 05SLOWBALT
> 
> Strongly agree with Southern.
> 
> ...


So just to make sure I get it lol I have a drop every three feet right now but when I go with the INSULFROG I should also put in a drop at the diverted rail?


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