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Rick Gibson

Droppers for fiddle yard - help!

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I’m beginning an extension to my layout which will be my first venture into DCC. I intend using Peco modified electrofrog points with SEEP motors (the built in auxiliary switch will activate the frog). Are the twelve droppers correctly placed and needed? Especially number 4 which I’m not sure is needed? Any help would be much appreciated. The droppers will be attached to a DCC bus.

 

My current layout is 009 but has a straight length of standard gauge track running across it (no points). This fiddle yard would allow standard gauge engines to do something a lot more interesting than run backwards and forwards on the existing layout!

37D2D467-533A-4FFE-9547-AFE189376D48.jpeg

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Only issue I can see is the turntable, you need a commutator or similar to switch the polarity as the table rotates or it will short out. Better with 4 than without. 

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Yes, the turntable needs to switch polarity of the tracks at roughly 90° to the main direction of travel so that there is no chance of a short circuit when turning locos.

There are also some lengths of track on your plan which do not have droppers. The best practice is to fit droppers to eacch individual length of track so you don't have to rely on rail joiners for conductivity.

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with SEEP motors (the built in auxiliary switch will activate the frog).

you'll regret that decision :D

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11 hours ago, Gavin Liddiard said:

Yes, the turntable needs to switch polarity of the tracks at roughly 90° to the main direction of travel so that there is no chance of a short circuit when turning locos.

There are also some lengths of track on your plan which do not have droppers. The best practice is to fit droppers to eacch individual length of track so you don't have to rely on rail joiners for conductivity.

 

I agree with the point about droppers on each bit of track although, if the fiddle yard is not in view, it does not need to be "pretty so you could always solder jump wires round the joiners.

 

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Posted (edited)

Hi, as mentioned above I would certainly add a dropper to every individual rail section, it sounds like a pain but will be worth it for DCC operation (when re-wiring Charwelton to DCC the 18 road fiddle yard needed over 700 droppers so it’s not too bad on your set up).

   Also I think there is a “positive” feed missing on the section between the points under the “negative” labelled 4. Also you will need one after the frog on the point fed by feed 7 “negative”. Assuming all frogs are fitted with insulators to stop shorts.

Edited by 43110andyb
To add extra dropper info
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41 minutes ago, 43110andyb said:

Also I think there is a “positive” feed missing on the section between the points under the “negative” labelled 4. Also you will need one after the frog on the point fed by feed 7 “negative

What 40110andyb said but in pictures See drawing  dropper 13 & 14

 

droppers.png.b7ef43102cffd718031782a061149ce4.png

 

 

The black side of feed 4 is necessary, the red side is not necessary but as JimFin said 

17 hours ago, JimFin said:

Better with 4 than without. 

The above modified drawing shows the minimum number of droppers need to make the layout work

But as Gavin says

15 hours ago, Gavin Liddiard said:

The best practice is to fit droppers to each individual length of track so you don't have to rely on rail joiners for conductivity.

John

 

 

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Posted (edited)

Thanks John ks! Far better on a diagram!  I did also mean this feed on the point, after the frog there will be no feed into the next (hopefully it can be seen on the diagram).

84CC3025-44E5-4DC0-8F56-65B6F377F8AA.jpeg

Edited by 43110andyb
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50 minutes ago, 43110andyb said:

Thanks John ks! Far better on a diagram!  I did also mean this feed on the point, after the frog there will be no feed into the next (hopefully it can be seen on the diagram).

If you mean the blue arrow it should get a feed from dropper 3 (black connection ( highlighted rail to show where that dropper feeds)) provided you are happy to rely on fishplates

insulated fishplates show in white

 

959216928_droppers2.png.cc777fedc2d4d653c81f03e28555ea0a.png

 

You could eliminate 2 points by running all 4 tracks to the turntable. provided the turntable is suitable

John

 

 

 

 

 

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10 minutes ago, John ks said:

If you mean the blue arrow it should get a feed from dropper 3 (black connection ( highlighted rail to show where that dropper feeds)) provided you are happy to rely on fishplates

insulated fishplates show in white

 

959216928_droppers2.png.cc777fedc2d4d653c81f03e28555ea0a.png

 

You could eliminate 2 points by running all 4 tracks to the turntable. provided the turntable is suitable

John

 

 

 

 

 

Thanks -Yes sorry my mistake, just thinking where I would put them if I was wiring -feeding into point at both ends I would use as a rule of thumb for DCC but this would work just as well and be easier if space is tight! 

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9 hours ago, JST said:

 

I agree with the point about droppers on each bit of track although, if the fiddle yard is not in view, it does not need to be "pretty so you could always solder jump wires round the joiners.

 

Rail is not a good conductor. If you are laying new track, you might as well do the job properly.

 

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Thanks for all this; I can see where and why you’ve suggested the two extra negative droppers. I’m assuming that insulting joiners are only needed on the two rails in the middle of the heel of all the points, but really kind of you to mark them in. However I’m unclear about the junctionmad comment regarding using electrofrogs with a switch to polarise the frog in the direction of travel. I can see that modifying the electrofrog is fiddly but is there some other

20 hours ago, Junctionmad said:

you'll regret that decision :D

kind of nightmare I’m unaware of?

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Posted (edited)

I have attached a modified pic of the OPs plan showing where I would fit droppers. You have to assume that rail joiners provide alignment allowing for expansion gaps, but not conductivity. It makes sense when laying new track to eliminate future problems that can be avoided at this stage.

I have omitted the droppers from the frogs that would be fed from the accessory switch on the point motor. Insulating rail joiners would be fitted to the frog rails on each point.

If you are planning on exhibiting the layout then I would recommend you fit two droppers per rail section for redundancy. This policy has saved us many times at exhibitions with Mostyn when droppers have failed over the years.

I would suggest you look at the MTB-MP1 point motor. I fitted 40 of these last summer to Mauch Chunk to replace unreliable Peco solenoid motors. They are very easy to fit and adjust and have a built in accessory switch: linky

image.jpg.8a5537dba84c66c9404524f2178e0e75.jpg

Edited by Gavin Liddiard
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22 hours ago, Rick Gibson said:

 I can see that modifying the electrofrog is fiddly but is there some other

kind of nightmare I’m unaware of?

 

Relying on SEEP PM1 contacts to power your common crossings or drive LEDs is a bit risky. They are not precision instruments and require very careful positioning when installed. The travel of the solenoid bar must be absolutely in line with the travel of the point tie bar, and the point operating wire must be perfectly perpendicular and not touch the edges of the hole in your baseboard through which it passes. The central position of the solenoid bar/operating wire must be exactly the same as the central position of the point tie bar. If you get all of those right, the travelling distance of the brass washer along the contact strips will be just right for reliable reporting of point blade position to whatever is at the end of your wires. If any of them are not true, you will have a problem at some time or other.

 

This response has no connection with droppers (your topic heading) but you did mention SEEPs. :D

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38 minutes ago, Junctionmad said:

Yes the nightmare that is SEEP point motors. 

Been there, done that, gone elsewhere.

The Seep is probably the cheapest point solenoid available, there is a reason why...........

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Posted (edited)
21 hours ago, melmerby said:

Been there, done that, gone elsewhere.

The Seep is probably the cheapest point solenoid available, there is a reason why...........

 

Followed closely by the Peco solenoid point motor which is also a reliability nightmare.

After an eventful show at Glasgow 2019 with Mauch Chunk where we had no confidence that the fiddle yard points would switch as desired, we replaced all the peco solenoid point motors (approx 40) with MTB-MP1 which also required the change of accessory decoders from MERG to Digikeijs DR4018. At its next show, Warley 2019, the new point motors worked perfectly although one operator complained that he couldn't hear them....

 

50079105082_e2b425b790_b.jpg20190715_202422 by Gavin Liddiard, on Flickr

 

This pic shows one of the fiddle yard boards on Mauch Chunk showing the dropper arrangement with two droppers per rail for redundancy. The yellow droppers go to the frog rails and are fed from the accessory switch on the MTB-MP1 point motors.

There are two main track buses on this board as we use PSX circuit breakers to split the layout into 4 power districts with 2 on the scenic and 2 on the fiddle yard. This minimises down time when there are shorts on one part of the layout.

Edited by Gavin Liddiard
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