Short Circuit Issues : Electrofrog Points

[Blobrick]

I am hoping someone here on the RMweb will be kind enough to help me with a problem of my own making?

 

I have just finished laying out the storage yard for my new layout. The layout has to be long and thin to fit into one end of the spare bedroom, This results in the layout being surrounded on three sides which means that the rear to almost inaccessible. For that reason l decided to build the yard first. The baseboard has no access underneath so all point motors are of the surface mounted kind. This has meant that there is nowhere to fit any polarity change over switches, therefore l ve elected to use Electrofrog points and use the switch blades to feed/isolate each road in turn. I had previously built simple ladder yards using these points before without issue so assumed l could do the same here.

 

The main difference in this design was that the yard is fed from either end using double junctions with Insulforg diamond crossing, so no insulation issues there?

I suspect the issue lies with the "Turn Back" siding, and to this end l have attempted to work out where the fed/short is coming from and so far l have cut through three fish plates (Shown in Red on diagram) After cutting these and spending a couple of hours today attempting to trace the issue with a meter and getting nowhere l decided l need some advice

 

I would love to be able to resolve these issues without having to rip the whole thing up, access would be difficult as to enable me to test everything l fitted the front boards, screwed and GLUED D'OH, so l am keeping my fingers crossed that is something simple l ve missed?

 

 

 

Any help would be very much welcomed

 

Bob C

Layout Doc.pdf

[Spitfire2865]

Electrofrogs really shouldnt rely on switch rail conductivity. Thats just asking for issues.

How did you actuate them without frog polarity changing?

Did you use insulated fishplates?

Multiple feeds throughout would have been best. That can be added after though.

[Blobrick]

Electrofrogs really shouldnt rely on switch rail conductivity. Thats just asking for issues.

How did you actuate them without frog polarity changing?

Did you use insulated fishplates?

Multiple feeds throughout would have been best. That can be added after though.

 

 

Hi Spitfire

 

Yes you are quite correct, I knew l was "winging it" when l tried this idea, I have in the passed got away using these types of point in a simple ladder configuration, and thought l d worked out all the possible permutations as to switching arrangements, alas  as l now know that not the case.  As for multiple feeds, l m not sure where l d mount any change over switches?. The only other option would be to feed each road off a switch on the control panel, but to get that to work l d still need to work out where the breaks and feeds would be

 

Bob C

[Titan]

Hi Spitfire

 

  As for multiple feeds, l m not sure where l d mount any change over switches?. 

Bob C

 

What you can do is use latching relays for the switches with the relay coils in parallel with the point motor coils. You can mount them anywhere you like then. Only disadvantage is that if you switch the points manually the relay wont work and it won't change over. 

[Blobrick]

Assuming this is DC, I can see what goes wrong. You'll need to do the following: insert insulated rail joiners (IRJ) on all rail heads leading to the return track, from both directions (that's 8 IRJ's!). So, not only the ones you've installed already, but on the other side as well (in the same place as the Up side, but on the Down side) No real requirement to use a relay, but you then need a DPDT switch, wired such that you can choose between the Up and Down tracks as appropriate.

 

Because what's happening here is that you have the Up and Down tracks wired oppositely: the positive rail on the Up side is the negative rail on the Down side, and vice versa

 

 

Good evening DM

 

Many thanks for identifying the source of my problem, I had though about isolating the turn back siding and feeding it via a panel mounted switch, l had thought of cutting all remaining IRJs but held off in case l had missed something simple.

Right l ll have a quick cutting hour and let you know what happens!

 

Many thanks

 

Bob C

[Suzie]

I think that latching relays is the way to go with insulated joiners in all the frog rails. If you are DC you will need 2-pole relays so that you have one for the frog switching and one for the power routing.

 

You are right that it is the turnback that is causing your problems. I think I would have used single slips instead of the diamonds and used UP-SDG3 for the turnback!

[Grovenor]

Because what's happening here is that you have the Up and Down tracks wired oppositely: the positive rail on the Up side is the negative rail on the Down side, and vice versa

Not according to the diagram provided, but its irrelevant anyway, the 8 insulation and changeover switch is required regardless.

Regards

[Blobrick]

Assuming this is DC, I can see what goes wrong. You'll need to do the following: insert insulated rail joiners (IRJ) on all rail heads leading to the return track, from both directions (that's 8 IRJ's!). So, not only the ones you've installed already, but on the other side as well (in the same place as the Up side, but on the Down side) No real requirement to use a relay, but you then need a DPDT switch, wired such that you can choose between the Up and Down tracks as appropriate.

 

Because what's happening here is that you have the Up and Down tracks wired oppositely: the positive rail on the Up side is the negative rail on the Down side, and vice versa

 

Evening DM

 

I ve tried, as you suggested, cutting all connections to the "Turn Back" siding. The siding is now electrically dead. However l am still getting short circuits when both the Up & Down lines (both ends)  are set into the yard. I can only get the Down sidings to work with the Up Line set for the Main Line. If the Up line is set for the yard there is a part feed to the  Down line, which does not clear if the Down is then set for the Main line......... mucho head scratching here!!

 

 

Bob C

[Blobrick]

I think that latching relays is the way to go with insulated joiners in all the frog rails. If you are DC you will need 2-pole relays so that you have one for the frog switching and one for the power routing.

 

You are right that it is the turnback that is causing your problems. I think I would have used single slips instead of the diamonds and used UP-SDG3 for the turnback!

 

Hi Suzie

 

I ve just chopped all electrical connections to the Turn Back Siding and l am still having problems. As for the design of the yard, it was laid out using what l had awaiting to be used. I  ordered a second diamond crossing but was sent an electrofrog one, however l had a spare ( insulfrog) single slip which l used instead at the junction at one end. If l had realised that l was going to create these issues l might have chosen a different route (No pun intended!)

 

Bob C

[Silver Sidelines]

I am wondering if I have missed the 'point'.  But surely you have missed out all the insulating rail joiners?

 

Incidentally - if you are using Peco Electrofog frogs they work just fine on DC relying on the point blades to switch the current.

 

Ray

[Blobrick]

I am wondering if I have missed the 'point'.  But surely you have missed out all the insulating rail joiners?

 

Incidentally - if you are using Peco Electrofog frogs they work just fine on DC relying on the point blades to switch the current.

 

Ray

 

Hi Ray

 

I had used electrofrog points in this sort of configuration before, due to similar situation where l had no room to fit change over switches and found a simple ladder could be fed from the toes without the need for IRJs. If these points formed on half of a set of loops, as long as both sides of the loop moved together there were no issues. My latest idea was based on this "ladder" abet with a turn back road in the middle.

A fellow member suggested isolating the turn back siding as it was the "Common" between the Up & Down lines throught the yard, the siding has been insulated but l am still getting short circuit. No doubt its something really simple l ve missed, but until l find it.............

 

Bob C

[Silver Sidelines]

Hello Bob

Hi Ray

 

I had used electrofrog points in this sort of configuration before,............

I see what you say but......   I use cab control and sections.  IF I was wiring up your track configuration I would have insulating rail joiners across all the lines with separate feeds at either end of the layout.  In other words one feed for the left hand end of the layout, and one feed for the right hand end.  In theory with Cab Control (and common return) you only need insulting rail joiners on one side of the track but I am perhaps over cautious and completely separate each section with insulating rail joiners on both rails.  I cannot help feeling that with the latest Peco points there may well be a hard wire connection (beneath the points) which is causing your short circuit which would be easily solved by breaking the layout down into two sections as detailed above.

 

Ray

[Grovenor]

just trace through the rails, colour one side red and one black, wherever red meets black you need insulated joints.

You will find that setting routes from both ends to the same track you will be OK but if you set to different tracks from each end you will find red meets black, hence the short occurring.

Regards

[Joseph_Pestell]

From the drawing, I can identify two problems.

 

One (already mentioned I think) is that the turnback siding needs its own feed and a total of eight insulated fishplates.

 

But the main one is that you are feeding current from both ends. You need a insulated joints close to the exit from each storage road.

[Suzie]

This is my take on the minimum that needs to be done is here:-

 

 

Blue lines show insulated joiners, black triangles are the common return feed, and white triangles are power feed (possibly derived from power routing switches/relays) I have assumed dead frog crossings.

 

This version uses a dead frog single slip at one end as a comparison:-

 

 

Because it is a minimal installation some routes are very critical on how the points are set to ensure a feed.

 

[DCB]

I think the problem is the turn back which needs double isolators on both diverging routes at the heel of the Y points.  I use surface mount microswitches bearing on the point stretcher to operate either a DPDT relay or simply change the frog polarity.  I can't see how it can work without either a DPDT switch or Relay to change between up and down line feed

 

You don't need fancy feeds with DC, some of my points have been feeding sections around 15 feet, actually one does 35 feet for 30 plus years, still the same Peco code 100 electrofrog points.    DCC does need fancy wiring, the points cant take the load reliably. 

 

You could put isolators part way along the loops but having done this myself I would not recommend it. Just make sure the points at both ends of the loop are set the same way and throw simultaneously. Ideally also turn the track power off as you change them.  There will be a momentary short if one throws a fraction or equally a long period  before the other.    The reason for not putting isolators is metal wheeled stock can bridge the isolators and if one point is set against the other cause a short.  Locos bridging the isolator with points set in opposition can destroy plunger pickups as found on the Airfix 14XX. it can also damage loco to tender wires on modern locos with loco and tender pickup as the controller thermal cutout clicks away giving pulses of 1 amp or so (4 of so on DCC).

[Dagworth]

This is what happens on just one pair of roads with feeds at both ends.

 

.

 

You need to add isolating fishplates on both rails of every road

 

Andi

[davetheroad]

This is how I might do it with Dc and cab control

 

The turn back siding can be fed from either of the main lines via a switch

 

I always used insulated joiners on both the feed and return.

 

[Dunsignalling]

davetheroad's diagram is spot on.

 

Any switching of frog polarity will be in addition to this and, whilst desirable for long-term reliability, it is not essential to make the thing function.

 

The basic principle is to put insulating joiners on both rails wherever a point can (even potentially) receive a feed from the "wrong" end, then add extra power connections to feed any dead areas. 

 

It doesn't matter that a rail is live on either side of an insulated joiner, the essential thing is to prevent the frog being fed from the heel end.  

 

If you keep to correct principles everywhere, you don't get nasty surprises arising from later alterations to other parts of the layout that create new back feeds.

 

 

John  

[Suzie]

...It doesn't matter that a rail is live on either side of an insulated joiner, the essential thing is to prevent the frog being fed from the heel end...

 

If you have the same feed from both sides the insulated joiner is unnecessary.

 

If you put the insulated joiners at one end of the loops it does reduce the need for setting the points at both ends. In my diagram you only need to set the points at both ends when leaving the up and down loops.

 

 

 

With a complicated track layout like this it is always going to be operationally a bit difficult unless full power routing or fancy cab control is implemented - using the switch rails to feed the power is less than ideal for more than just the reliability issues.