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Electrical continuity for turnout blade rails


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We have a conundrum - the layout is already built and track laid with a mixture of electrofrog and insulfrog turnouts. The operation of the turnouts is completely manual (BHS) and therefore is relying on physical contact between blade and stock rails to provide electrical continuity. We know this is not ideal but is was built many years ago with little technical knowledge. The turnouts are quite old and therefore do not have the wires that can be cut to separate the blade rails from the frog rails so bonding blade to stock will not be possible.

 

Given the existing situation, what can be done to provide a more reliable electrical connection of blade to stock? We have considered using wire-in-tube operated by slide switches so providing a switch to complete the circuit. Any other, possibly less complex, solutions?

 

Thanks

 

David

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On part of my layout I added microswitches operated by the bar that joins the point. You would have to add the wiring to the frog which would then run back to the points. This still  leaves the open point opposite polarity to the adjacent rail. (This assumes electrofrog points.)  

EOY4994.jpg.59b86002e5a5c436bc2d69fa187fd2a3.jpg

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5 hours ago, BR60103 said:

On part of my layout I added microswitches operated by the bar that joins the point. You would have to add the wiring to the frog which would then run back to the points. This still  leaves the open point opposite polarity to the adjacent rail. (This assumes electrofrog points.)  

EOY4994.jpg.59b86002e5a5c436bc2d69fa187fd2a3.jpg

 

I had thought of that as well, I assume they are double pole switches so contact is made which ever way the turnout is switched.

 

 

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If your points are completely manual, by which I understand "poking finger", then anything is going to be more complex.

The slide switch and wire in tube is pretty simple and its difficult to think of anything more straightforward. If you don't mind the visual intrusion, then microswitches might be ok, but they are the devil to set up accurately!

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46 minutes ago, ikcdab said:

If your points are completely manual, by which I understand "poking finger", then anything is going to be more complex.

The slide switch and wire in tube is pretty simple and its difficult to think of anything more straightforward. If you don't mind the visual intrusion, then microswitches might be ok, but they are the devil to set up accurately!

My thoughts exactly, thanks

 

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18 hours ago, rynd2it said:

 

I had thought of that as well, I assume they are double pole switches so contact is made which ever way the turnout is switched.

 

 

They are single pole double throw.

 

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I do the same outside in a station usually covered by a Rabbit hutch like cover with digit operated points, Digit, not Digital.

 I use tiny Chinese micro switches which are about 10p each. The common wire goes to the frog and the other two to the respective rails at the point toe.  If using dead frog points link the rails at the frog and effectively live frog them.  The next problem is the point blade pivot can go high resistance especially on DCC, bridging that needs a very delicate touch on the soldering iron and some very flexible wire.   In the totally exposed to the weather bit I have one point with a sealed change over reed switch operated by a super neo magnet.

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5 hours ago, Sol said:

The frog is electrically isolated from the blades which are bonded underneath to the stock rails

One of many on the Internet  ....  http://www.mrol.com.au/Pages/Vu/LiveFrogWiring

 

As I said at the beginning, the turnouts are a mix of live and insulated frogs, they are old and therefore the bonding wires are not there and the track is already laid down. So I need a method that connects one blade to it stock rail while disconnecting the other blade from its stock rail.

 

DPDT switches would do this but how to use them? The two methods suggested seem to indicate wire in tube and slide switches is the best option.

 

Thanks all, 

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Isolation  of blades from frog can be done in situ using a dremel to cut rails & bonding also done in situ - drill down next to blades & stock rails , solder a wire to blade rail, down thru one hole, up the other to the stock rail, this works both for DC & DCC.

 

Granted, it is a bit of work but it works.

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10 hours ago, Sol said:

Isolation  of blades from frog can be done in situ using a dremel to cut rails & bonding also done in situ - drill down next to blades & stock rails , solder a wire to blade rail, down thru one hole, up the other to the stock rail, this works both for DC & DCC.

 

Granted, it is a bit of work but it works.

No, not with these old points. Cutting blades cuts them totally free with no base

 

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7 minutes ago, rynd2it said:

No, not with these old points. Cutting blades cuts them totally free with no base

 

 

Do you have a multimeter ? 

 

Can you confirm that the two blades are not electrically connected to each other within the turnout's existing wiring ?   If so, a switching option may be possible which isolates the blades.   But if not, and the two blades are electrically connected, then there isn't a solution which doesn't involve a saw or cutting disc. 

 

 

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1 hour ago, Nigelcliffe said:

 

Do you have a multimeter ? 

 

Can you confirm that the two blades are not electrically connected to each other within the turnout's existing wiring ?   If so, a switching option may be possible which isolates the blades.   But if not, and the two blades are electrically connected, then there isn't a solution which doesn't involve a saw or cutting disc. 

 

 

I know this hence the post

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DPDT slide switches are readily available and will allow you to do what you are asking, use one contact set for the left hand switch and the other for the right hand switch. This will work equally well for insulfrog or electrofrog as it is just supplementing the blade-stockrail contact.

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3 hours ago, rynd2it said:

No, not with these old points. Cutting blades cuts them totally free with no base

 

 Sorry if you thought I meant to cut the moving blades  but cut up near the frog. as you can see from one of my frogs - -now like a dead Unifrog

 

IMG_0649.JPG

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Going back to the top.  You can live frog the point by either adding a fillet of solder to the dead frog points with the sliver of plastic or by filing up an arrow head shape from rail and melting and soldering it into pace on the big plastic blob frog on the earlier type.

With the frog live you can switch the frog with an spdt switch and feed the rails down towards the blades.  On a Peco point bonding the blades is extremely unusual. I doubt anyone does it. I have never read of anyone doing it, the blade relies on contact through its pivot and between rail and blade, sometimes with a tag, often not.    That pivot becomes the weakest link in an overload situation, or outdoors.  You could bond the point blade to the adjacent rail with some super flexible wire, maybe braided motor brush or car alternator brush wire but it will have to withstand thousands of operations and need some pretty fancy soldering down in amongst the rails.

The points illustrated by sol have a built in short if you start cutting wires and bonding, the wheels on the curved route run over the end  of straight rail at the frog, whch is at the reverse polarity.  Its not a problem out of the box.  The insulation is just a sliver. I test trackwork with a test loco with only one axle pick up. It should be able to crawl all over the layout without stopping

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10 hours ago, Grovenor said:

DPDT slide switches are readily available and will allow you to do what you are asking, use one contact set for the left hand switch and the other for the right hand switch. This will work equally well for insulfrog or electrofrog as it is just supplementing the blade-stockrail contact.

Thanks, that is the best solution

 

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5 hours ago, DavidCBroad said:

Going back to the top.  You can live frog the point by either adding a fillet of solder to the dead frog points with the sliver of plastic or by filing up an arrow head shape from rail and melting and soldering it into pace on the big plastic blob frog on the earlier type.

With the frog live you can switch the frog with an spdt switch and feed the rails down towards the blades.  On a Peco point bonding the blades is extremely unusual. I doubt anyone does it. I have never read of anyone doing it, the blade relies on contact through its pivot and between rail and blade, sometimes with a tag, often not.    That pivot becomes the weakest link in an overload situation, or outdoors.  You could bond the point blade to the adjacent rail with some super flexible wire, maybe braided motor brush or car alternator brush wire but it will have to withstand thousands of operations and need some pretty fancy soldering down in amongst the rails.

The points illustrated by sol have a built in short if you start cutting wires and bonding, the wheels on the curved route run over the end  of straight rail at the frog, whch is at the reverse polarity.  Its not a problem out of the box.  The insulation is just a sliver. I test trackwork with a test loco with only one axle pick up. It should be able to crawl all over the layout without stopping

I'm not trying to create a frog polarity or even make them live. The problem we have is, as clearly stated in the OP, is electrical connection between blade rail and stock rail. In quite a few cases, when switching the point the blade remains dead.

The solution is wire in tube and DPDT slide switches.

 

Case closed, thanks

 

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