sparking/electrical problem with Peco points

Hi all
Here's a baffling little problem for us to chew over. We have had Soberton out at the TRPS Show in Ferneham Hall yesterday and the fiddle yard was
right at the back of the stage which was dimly lit. This allowed me to see the full extent of a problem we have known about for a couple of months, but has obviously been going on for quite a while.
The problem we are seeing is that when trains cross any pointwork (the throats of the fiddle yard are probably the best example) we are seeing sparking, almost as if we were looking at electrical units sparking over gaps in the third rail. The points are all Peco Streamline. The stock involved seems to be almost anything and everything; Bachmann, Hornby, the odd re-wheeled Lima, steam and diesel outline.
To begin with people were blaming old style metal tension lock couplers shorting from live chassis to frog, but in the dim light yesterday I was able to see the true nature and full extent of the problem (and examine the damage that is being done). This sparking seems to be happening towards the tips of the point blades and frankly a couple of the blades I looked at ought to be changed so this has obviously been going on for a long time. I am guessing that there is corresponding damage to the wheels as well but so far I have not been able to find any on my stock.
As far as I am aware the points are all insulfrog and the wiring of the points is totally "standard" but the evidence seems to suggest that somehow the point blades are actually at a different potential to the adjoining stock rails, and that the inner flange face of any slightly out of gauge wheels are managing to bridge the gap thus causing the sparks to fly (no, I didn't have a chance to get the meter out and check but I plan to the next time the layout is out). Also, we are not using any fancy electronics such as HF track cleaners.
Question: has anyone encountered similar problems and can they point me in the right direction to find a cause?
Thanks in advance.
Elliott
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There is a bonding wire which joins each switch rail to the frog rails, when the switch is open it makes it rail the opposite polarity from the running rail it is next to, the sparks are caused by wheelsets touching the swtich and running rails at the same time (probably bogie stock).
If you can lift the points then simply remove the bonding wire (its underneath and impossible to remove without lifiting), if you can't lift the points then you either have to live with it or cut a new gap with a slitting disc or similar tool.
This then introduces the problem that your switch rails then rely on mechanical contact to work so you can solder some bonding wires from the each switch to its relevant running rail.
hth,
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DAS
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when
Thanks Dave, but I have always understood that this only applied to live frog points. We had deliberately chosen insulfrog for use in the yard in order to "keep it simple". Can you confirm/deny?
Elliott
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Are all your points definitely Insulfrog ??? - I have had this proble with live frog, with dead frog I cannot see how you can get sparks aside from dirt - or someone has bonded the switch rails to the frog (well just beyond) ....
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I'd like to query that.
We are talking insulfrog points aren't we? The points on my layout have a bonding wire connecting the switch rail to the appropriate frog rail, so there are two bonding wires.
This means that if there is no feed at the frog end, and the points are set straight, then the curved switch rail should be at zero volts. If this is not the case, what is being fed at the toe end of the points?

On my garden layout I have bonded the switch rails to the adjoining stock rails without the necessity of cutting any connections already existing.

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Jane
OO in the garden http://www.yddraiggoch.demon.co.uk/railway/railway.html
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Then I'll answer it.

I am trying to find a solution to the OPs problem, I have not attempted to dicuss the merits of the alternatives to wiring a layout. I can only assume that either the problem is not exactly as described or points are actually live frog.

The OP can of course bond the switch to the stock rails as you suggest and get a dead short if the points are live frog and still bonded underneath - might be a useful way of confirming if they are live or dead frog, personally I wouldn't do it.
Rather than (incorrectly) criticising my response why don't you suggest a dead frog reason why the OP has the sparking problem.
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Maybe you ought to go to the opticians to get your eyes tested. I can tell the difference between live and dead frog points just by looking at the frog.

Because your response was wrong.
Maybe the contact that is fixed underneath the switch blade and connects it to the stock rail has bent out of position, and the only electrical contact is between the touching rails.
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Jane
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So can you see the OPs layout from where you are then ? and you can confirm that the points are dead frog ? - I'll take that as a "no" shall I ?

No it wasn't - it was correct if he had mistaken dead/live frog points (as others have questioned) and was far more helpful than your suggestion .... oh you didn't make one.

Go and score points elsewhere - reply to the OP with your solution.
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I refer the honourable gentleman to the original poster's original post: <quote> As far as I am aware the points are all insulfrog and the wiring of the points is totally "standard" </quote>

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Jane
OO in the garden http://www.yddraiggoch.demon.co.uk/railway/railway.html
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"AS FAR AS I AM AWARE" is the key bit here.
You are yet to post anything actually helpful to the OP.
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OK, In that case, and to stop you from further bullying me:
Elliott,
How easy would it be for you to confirm that the points are in fact insulfrog, as suggested in your first post?
The answer to your follow-up question to Dave is that, yes, this only applies to live-frog points. However, you say in your first post that this sparking occurs when trains cross _any_ pointwork, but then you only mention the points in the fiddle yard. Does it happen on points in the main part of the layout? If so, this would seem to suggest that, as Dave implies, the points in the fiddle-yard are actually live frog and not the insulfrog that you thought they were.
If this is the case, I can give you a suggestion for how to get rid of the phenomenon: paint the back of the switch blades with some insulating paint to prevent them from shorting on any passing wheels. This should not affect the way the points switch current to the frog if you ensure that the paint does not get on the spring contacts that contact the underside of the running rails to do the current-switching.
There is a way this could happen with insulfrog points, but it is most unlikely. If, at the frog, a wheel were to bridge both frog rails, while at the same time a wheel were to bridge the gap between the switch blade and the stock rail, you would get a short. In my experience the only wheels that bridge both frog rails are original Lima, but you say that you are getting the sparking with all sorts of wheels, so as I say this is most unlikely.
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Jane
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Just when I thought you had said something useful you demean yourself with such a comment - disagreeing with you is not bullying.
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DAS,

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Dave Skipsey wrote:

If the turnouts in question were live frog wrongly wired then there would be a dead short 'CRACK' each time the turnout was thrown and the overload cut-out would cut out - 'BANG'. That's not the symptom described.
Regards, Greg.P.
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Not if unsulated at the frog ....
That IS the sympton described.
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Dave Skipsey wrote:

I'm sure the symptom was sparking visible in low light conditions.
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Simple solution then - keep the lights bright.
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Dave Skipsey wrote:

LOL! Reverse lateral thinking - Did you by any chance work for Lucas in the past? ;-)
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Nope - only BNFL ..... :>)
Just trying to reinject some humour.
I notice the OP has vanished and not answered any of the questions put to him ????
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Dave Skipsey wrote:

I'm sure we scared him off!
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I don't hae a lot of experience of stuff like this, but could the rail that moves (to select the track) be wobbling as the train goes across. Said wobbling could make and break contact with an energised rail and if there are wheels on the blades it would make a circuit.
Unlikely to be anything as complicated as that but you never know!
peter
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