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Yard / Point Question


thornabydemon

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Hi,

 

Had a lot of help on here being new to DCC has got me alomst there, I have two large oval circuits working well with cross overs and loops for the station but when I have come to the yard I have hit a problem.

 

Now the first question being what is the easiest way to draw track diagrams to ask a question as the next bit may get confusing?

 

The main question, everything works perfect so far except my yard, the is an entrance from the main line which is fine, the first point has another three running from it in typical yard fashion and all great no problems, but when I switch that first point to enter its running line it just has no power once off the point. and as I say the other three that feed off are fine, the track after is fine but when they reach the points at the other end they short.

 

So the question essentially is when points face each other in a yard situation how do you wire them/use IRJ's etc.

 

Layout is OO code 75, all points are peco electrofrog and I have modified them all with joins etc and IRJ's on the V's will be using motors but nothing wired up at all with the wire from the frog not attached to anything.

 

Really scratching my head and need some help here,

 

Alex

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The rules apply in every situation - learn them and you will never need to ask a question again. Some will tell you the rules are overkill - and they are - but they work every time whereas the shortcuts do not.

 

1. a dropper from each stock rail.

2. an IRJ on EVERY frog

3. power feed to the frog from a spdt switch on the tie-bar (eg Tortoise point motor - or equivalent)

 

If you are doing this then the only possible fault (other than bad connection) is the feed from the spdt is wrong. (centre pole should go to frog, the other poles go to the appropriate rails of the bus.

 

Each yard line will also have its feeds from the bus. The IRJs prevent any shorting and allow the locos to have power for lights and sound even when the point is set against them.

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The rules apply in every situation - learn them and you will never need to ask a question again. Some will tell you the rules are overkill - and they are - but they work every time whereas the shortcuts do not.

 

1. a dropper from each stock rail.

2. an IRJ on EVERY frog

3. power feed to the frog from a spdt switch on the tie-bar (eg Tortoise point motor - or equivalent)

 

If you are doing this then the only possible fault (other than bad connection) is the feed from the spdt is wrong. (centre pole should go to frog, the other poles go to the appropriate rails of the bus.

 

Each yard line will also have its feeds from the bus. The IRJs prevent any shorting and allow the locos to have power for lights and sound even when the point is set against them.

 

Hi,

 

Thanks for the reply, 1 & 2 are both check and done in all instances.

 

Now for 3, thats a no, I am fitting Seep's but was planning to do this further down the line as all the points on the main including loops work fine I didn't see the urgency, likely to lead to the problem?

 

Alex

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As long as the IRJs are fitted then it will mean that the power at the frog only will be at the wrong polarity when switched. That means the feed at that part of the point will be incorrect when you throw the point. Depending on the point this may result in a short, but certainly no signal in DCC.

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With you, but what I don't get is I have around 30 electrofrog points on the layout all modified accordingly and the 14 or so on the two ovals which includes loops and crossovers work perfect, no short or loss of power, the point that goes to the yard is perfect and the five points joined in a 'ladder' to form the yard entrance again are sweet, its simply the points at the other end of the yard that short and one point off the 'ladder' that doesnt short but provides no power to the track after.

 

It's the inconsistency thats driving me mad as its all gone so well so far, but this has really stumped me.

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Hi,

 

Thanks for the reply, 1 & 2 are both check and done in all instances.

 

Now for 3, thats a no, I am fitting Seep's but was planning to do this further down the line as all the points on the main including loops work fine I didn't see the urgency, likely to lead to the problem?

 

Alex

 

Hello Alex

 

Well, I have done the same (used SEEP motors with no switches) and have used the "Frog Juicer" from Tam Valley. This works like an auto-reverser, and switches the polarity of the frog as soon as a short occurs. This works well as an alternative to microswitches on the points. It may not be relevant to your actual problem, but it is an alternative way to implement Rule 3...

 

The Frog Juicers have basically 3 terminals - Track A, Track B and the Frog. It switches one or other of the Track wires to the Frog, and does this with a solid-state switch (transistors) so there are no moving parts. They come in single, dual and hex (six) way versions, and you can get them from Digitrains (no connection except as a satisfied customer).

 

Regards

Chris

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Hi,

 

Thanks for all the replies, I spent quite some time working on the layout last night and had quite a few breakthrough's and as you have sugested/probably expected it was issues around polarity, sadly the job was made a bit harder by me being over confident originally and securing quite a lot of the track.

 

So, and I promise to try and close this up, I see the suggestion from Chris above which I will look into, and am starting to understand the role of the Seep's which am guessing would resolve a lot of the issues in themselves but also with what I did last night I used more IRJ's around the points, I had originally placed them on the V/frog's but as per the original post I had issues, but by isolating the points where they go 'against' each other and using their own feeds from the 'toe' most of the problems were cleared.

 

So I guess the questions are;

 

1, Should I have isolated the points like this in the first place and thats expected in a yard situation where the points go against each other or should you just need to isolate at the frog?

2, By me looking to isolate the points via IRJ's completely is this is in essence what the Seep PM1's will do for me once all hooked up?

3, If I went with option one, bearing in mind it's in a yard would this compromise the slow running?

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1, Should I have isolated the points like this in the first place and thats expected in a yard situation where the points go against each other or should you just need to isolate at the frog?

2, By me looking to isolate the points via IRJ's completely is this is in essence what the Seep PM1's will do for me once all hooked up?

3, If I went with option one, bearing in mind it's in a yard would this compromise the slow running?

 

If you examine the situation when points face each other by placing IRJs on both frog rails of both points (as per the rule) then you will completely isolate the points from each other - there will be an IRJ on both rails between the points (as well as the other two rails leaving the frogs. This is the correct solution. The two frogs are supplied power from the point motor switch (Seep in your case) but note that the switches are independent of each other (or ganged) as they need to both supply the same polarity to the same crossing rail. Facing points are nearly always ganged (ie switched together) as it very rarely makes any sense to throw one point without the other unless you are deliberately trying to derail your trains.

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Hi,

 

Thanks for all the replies, took me a while and got my head around things.

 

All other loops and alike were straightforward and to use my very basic speak the 'inner rail' simply joined up before, during and after each point, though of course with the yard and random points (inner rail meeting outer rail etc) the polarity changes were the issue, not wanting to wire up the Seep's just yet which as Kenton says would have resolved the issue I have took Chris advice and purchased the frog juicer so will be able to have everything running when that turns up and simply do the Seep's at a later date.

 

Alex

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