Loco wheels bridging insulated fishplates

[Will Thompson]

Hello,

 

I'm currenting wiring my first DCC layout and have chosen to purchase all electrofrog points to aid smooth running - and also because I am hardwiring a number of older locos for DCC and was having issues with the coarse wheels shorting Peco insulfrog points.

 

Despite following wiring diagrams (what seems to me to be) pretty carefully, adding in Hornby's insulating fishplates in the correct places, I am finding that the wheels are bridging the insulated gap and thus shorting everything out. I wondered if this was just down to coarse wheels on older stock, so tried a modern loco but the wheels are still bridging the gap over the insulated section and thus shorting the system.

 

I am struggling to work out what to do next. I am obviously doing something wrong or misunderstanding the wiring. I'm pretty sure I don't have a reversing loop - the shorts are occuring when points are back to back as I join the outer loop with the inner loop as well as in the fiddle yard section.

 

Any suggestions much appreciated! Or feel free to point me to where this has been answered already. Full disclosure - electrics are not really my strong suit...

 

[RB51]

Hello Will, welcome to the forum. Don't despair one of the electrical guru's will be along shortly. To aid their diagnosis can you upload a sketch or photo of the problem area? A simple hand drawn plan is fine. R-

[Chrissaf]

Firstly, if you are using Electrofrogs then you are not using Hornby points (I assume PECO). All my track is PECO and Electrofrogs. There isn't a Hornby DCC point clip in my layout. You do not normally fit Hornby R8232 DCC point clips to PECO Electrofrog points. PECO use a completely different wiring regime. The complexity of which depends upon whether you want to take full advantage of the Electrofrog feature. PECO use a lot more insulating rail joiners with Electrofrog points, this requires far more pieces of track to be given their own power connection as a result.

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With regard the layout shorting out when you throw points to join an inner and outer loop. Then you have most likely got the power connection reversed on one of the loops. Have a look at Section 5 and 6 of my 'Extension Pack' document downloadable from here. OK it is written for Hornby insulfrog track not Electrofrog, but it will still explain how to connect two ovals together and keep the shorts at bay.

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It is difficult to give you specific advice as to what goes where without seeing your layout design. If you can draw your layout as a track schematic and post it back here, then more advice can be given. Use the the B&W 'Hill & Moon' icon shown below to upload an image in .JPG or .PNG or .GIF file format (.BMP not supported). Your posted image will not appear straight away, it will be held back for administrator approval (weekday UK office hours).

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Also indicate in your next reply, whether you want or intend to use the frog switching capability of Electrofrogs. Personally, I would as I can't see the benefit of using Electrofrog points if you don't. Also, tell us what (if any) Accessory Decoders you are or intend to use to switch points.

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[Will Thompson]

 Thanks both for these replies. I will sort out a diagram tonight and upload it.

 

They are all Peco points. I had not intended using the frog switching capabilities and was simply planning to install point motors powered by DC. The main reason I switched to electrofrog was that insulfrog points were shorting with the coarse wheels of older locos over the insulated V when I first started out in DCC.

 

Will upload a diagram overnight.

 

Thanks!

[2e0dtoeric]

I don't quite understand the header title.

Of course a metal wheel will bridge an insulated fishplate. You are looking at a tiny gap of maybe half a millimeter, so the metal wheel will momentarily be in contact with both sides of the rail as it passes over the joint. (It is acting like a passing-contact switch!)

If both rail pieces - either side of the insulated gap - are the same polarity, then nothing will happen, but if they are opposite polarity, then you get a short-circuit.

So - somewhere, you have a wire crossed!

[Will Thompson]

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Thanks for all the replies to this so far - much appreciated. I'm realising now (by the nature of the replies) that my move to DCC is being driven by a "problem solving" approach rather than careful planning and research in areas I am not clued up on. For example, I had insulfrog points shorting out at the V so I bought electrofrog points to "fix" the problem without being fully clued up on the way electrofrogs operate.

So this is undoubtedly what is causing me problems. I think I believed that the insulating fishplates stopped the shorting when fitting electrofrog points, but I had not taken into consideration the problems of opposite polarity - or the action I need to take to fix this. Still, all a learning curve.

Above is a rough plan of my layout so far. All the track is Hornby with Peco electrofrog points. I have shown where I have installed power (blue) and where I have added insulated fishplates (red). I have also marked the three places where I am getting a short when the loco runs into the points (s).

Thanks for your help so far!

[RDS]

With that layout there are no reverse loops, so it is likely that as 2e0dtoeric says above you have some wires crossed.  Check all your wire droppers are correct by following one rail all the way round, ensuring that each one is always connected to the same terminal.

(I don't have Electrofrogs myself but with DCC I had a similar layout to yours, with just one connection to the track on the inner loop and no insulated joins but point clips on each point)

[Chrissaf]

I have performed an evaluation of your layout plan. The two locations showing 'shorts' are almost certainly due to one or more of your current power connections being reversed. Unfortunately in your drawing you represented the power connections as a single black colour, so there is no way to see which way round the connections are.

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Again looking at your plan, there are a number of track sections that would appear to have no power at all because they are isolated by the frog rail insulated joiners that you have indicated.

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I also notice that the points leading to sidings have no IRJs on them. This would be normal for an Analogue DC layout where you are using the switching of the point to connect power to the siding. And yes you could use that on a DCC layout as well.

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But consider this. If you have Diesel locos with lights or sound locos then if you switch the point away from the siding, the lights and sound go off. In DCC, it is recommended to have all the track live all the time. This means putting additional power feeds on the sidings, the result of which you then have to fit IRJs to the Electrofrog rails of the siding points as well.

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I have posted below a modified drawing that addresses these issues.

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• Firstly, all points have the IRJs fitted whether on a siding or not.
• Secondly, I have added additional track droppers to cover not only the isolated sidings but the areas of dead track that your original drawing indicated (you may have additional droppers on your layout that you didn't include in your drawing).
• Thirdly, AND MOST IMPORTANTLY, I have colour coded the droppers in Blue and Brown. You need to check the dropper polarity of ALL your existing power droppers and ensure that they are consistently the right way round. Use my Blue & Brown colours as a guide. I am 90% sure that one or more of your currently connected droppers are the wrong way round. And it is this error causing your shorts. This would most likely have been the same issue on your previous Insulfrog layout as well.

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TIP for placing droppers on a oval based layout to maintain consistent connection polarity.

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Place a wagon on the layout with a piece of tape on one side of the wagon. Decide on the dropper wire colour you are going to associate with the taped wagon side. Using my Blue & Brown example in my drawing. Let us assume that the side of the wagon with the tape is Blue. Now as you push the wagon around the layout and through the points (never lifting the wagon off the track). Whenever you arrive at a dropper installation location. The taped side of the wagon shows you what rail to attach the Blue wire to.

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[Creeping Jane]

Hiya - there is quite a good tutorial on wiring electrofrog points

Things to note are the insulated rail joiners are on the two parts of the frog  where the train would leave, ie the bit of the frog that he wires. I won't mention the name of the point motors (mentioned in the vid), but they seem to make a sensible choice.

 

Everard Junction has some very good tutorials on many aspects of railway modelling - it would be worthwhile checking them out and/or subscribing.

 

HTH - Pete

[Chrissaf]

Will, Just to add for clarity. The link that Creeping Jane provided to Everard Junction provides wiring details for the implementation of frog switching. In your reply timed at 16:53 you stated that you were not contemplating switched frogs.

[Will Thompson]

 All,

 

Thank you so very much for engaging with this so thoroughly - I had not expected such a service!

 

You're quite right about sections I had not powered up yet, I was just trying to work out what was happening at the points.

 

I will certainly add all the additional drops and more importantly check the polarity all the way through. Thanks very much indeed!

[Chrissaf]

One additional comment. To eliminate the possibility of certain rolling stock wheels being the culprit for the shorts i.e. bridging adjacent rails rather than bridging IRJs.

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As Eric said in his reply timed 20:20 it is quite normal for rolling stock wheels to bridge an IRJ. However, when the layout is wired correctly there should be no short circuits created. Think about it logically, the loco has multiple wheel pickups. Thus the loco will bridge across the IRJ connection for some considerable time if the loco is travelling slowly across the IRJ joint.

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Take a paper clip, bend it into a horseshoe shape and use that to bridge across the IRJs (taking care to have the point in the appropriate route position). If bridging the rails each side of the IRJ with the paper clip still creates the short, then it is more likely to be the wiring issue I outlined in my last reply.

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Note: If the point is in the wrong position for the rail being checked with the paper clip, that will create a short and be perfectly correct and normal that it does. Hopefully the drawing below will clarify the correct paper clip / point positions for the testing procedure.

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[Creeping Jane]

Will - you need to take care of what Chris has said. His idea of using a truck to check the polarity is brilliant. He also re-iterated that you had not intended to use polarity switching; IMO it is essential that you do. Both P**o and S**p both have capabilies to do that for you, although the former requires adding an additional switch to the motor, which is why the S**p is a better choice. I have no idea if Hornby point motors offer this capability, but as they only make insulfrog points (to my knowledge), I doubt it. There is also some information in the DCC wiki pages , but they need to be interpreted with care as they indicate some contrary advice to the info in that vid.

 

As a further aside, when you are doing your wiring, assuming you are soldering, tin the wires (and the track) with solder before joining them, it will make the joins quicker and less prone to dry joints. Connections back to the controller (preferably via a bus system) should be made to all sides of the point and to all sidings to ensure complete connectivity, as Chris has already said. Also note that Richard uses separate buses for his track, points/accessories and signals, each with its own power supplies.

 

You will not need to use point clips if wiring as suggested in the vid.

 

Once you get it it all working, you will love the flexibilty that DCC affords - OK it can be a frustrating (and potentailly expensive) experience getting it sorted, but the results (IMO) are worth the effort.

[Chrissaf]

His idea of using a truck to check the polarity is brilliant.

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To be fair, it wasn't my idea. It is a technique described previously on the forum by others. I just nicked it.

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PS - It is quite OK to mention PECO and SEEP point motors.

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The PECO PL-13 switch will fit a Hornby R8014 point motor. Personally, I prefer the PECO PL-15 switch used with PECO PL-10 motors. Both the PL-13 and the SEEP (integral) switch are very finicky regarding alignment. By contrast, the PL-15 switch is adjustable and far more forgiving in terms of alignment. However the PL-15 goes between the motor and the point so should be fitted at the time of point motor installation. It isn't practicable to retrofit an existing point motor with the PL-15 because the point operating pin needs to be longer when the PL-15 is fitted. You can however retrofit a point motor with the PL-13 as it gets glued to the very bottom of the point motor.

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If you are using surface mounted point motors (any brand), then I would suggest using the GM500D Latching Relay board for frog switching.

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Of course the 'Rolls Royce' frog switching solution is to use a TamValley Frog Juicer as it is completely electronic with NO moving parts. Or if the DCC Accessory Decoder has not yet been purchased, then a brand/model with the additional frog switching contacts integrally built in is the ideal solution for live frog switching.

[2e0dtoeric]

A minor variant on the truck and tape polarity aid - I use an ancient old truck and made a little 'carrier' that fits onto it. The carrier has a felt pen on each side, one red, one black, and as I wheel it around the layout, at each rail section, I press on a lever which lowers the pens, and leaves a coloured dot on the bare board.

Then, assuming you haven't lifted the truck off, you can mark all your droppers with the appropriate colour in one go, then drill and solder later. If you have removed it, you merely need to match up the pens and an existing coloured dot, and carry on from there.

[Creeping Jane]

Now if you had modified the truck to drill the holes, drop the cables and then solder them to the rails, I would have been mightily impressed and maybe Network Rail would be banging on you door for ideas on how to modify their HOPS trains!

[2e0dtoeric]

Now that's an idea - - - - 😛 Two dremels, two reels of cable, and a mini-spot-welder - - - now - where can I get a working 240v micro genny that will fit onto an OO truck?

Don't answer that!  😎

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Back onto topic before we get told off!  😳

[Will Thompson]

Thanks for all the posts - this has been extremely helpful. I began work on problem solving last night and so far so good. I discovered I had indeed wired one of the rails wrongly which was causing the problems at the top of the layout.

 

With Chris' help and following his guidance I have amended this and resoldered the drop adding the IRJs in the correct place. All good so far! Will try and get the job finished tonight but all in all, I think it is fixed - so thank you very much indeed!

[Chrissaf]

Glad to hear progress is being made.....

[2e0dtoeric]

And nice to see an acknowledgement - a lot of people don't bother.  🤐