Frogs - Knowledge Gap

[Gwiwer]

The attached image shows the track plan relevant to this question. 
 

Track is Peco Code 55 flexi, the points are unifrog, the crossing is electrofrog. 
 

As set up the points work as insulfrogs - so far so good. But there is no power through the crossing at all. I had assumed that with an electrfrog crossing the route switched by what are effectively insulfrog points would be live throughout. It is not. 
 

There will only be one loco on the track so back-feeds are immaterial. What matters is powering through the diamond. 
 

So what is needed to get power through the crossing?  And is there a trick I can use to avoid complexity?  
 

Also is there an easy way to get those unifrog points to behave as electros?  As in jumping a wire across the plastic boss to power the frog tip?  Remember only one loco so power can backfeed but cannot short. 
 

Thank you.  
 

Edited March 1, 2023 by Gwiwer

[jpendle]

Hi,

 

You cannot feed the power through the crossing as you have suggested. The two frogs in the crossing MUST have their polarities switched depending on the route taken through the crossing.

Therefore they must be isolated from the rest of your track and have power fed to them through some form of switch.

Also you haven't indicated were your track power feeds are.

It looks like the frogs are not isolated at all, so if you were to connect all the other track to power you would get shorts at each frog.

The simplest way to control the crossing frogs would be with a Double Pole Double Throw switch wired to change the polarity of the frogs as required, remember that the frogs will always be at opposite polarities.

 

Regards,

 

John P

[dasatcopthorne]

How are you powering the points?

 

Dave.

[Gwiwer]

16 minutes ago, dasatcopthorne said:

How are you powering the points?

 

Dave.

Manually. Nowhere to fit motors on this project and no need for them in normal running. 

[Nigelcliffe]

You still need a switch as John P outlines above, and some insulated rail joiners.   The same switch could also operate the frogs on the two Unifrog turnouts at the same time, turning them into electrofrog. (Changed my mind having thought it through,  Simon below is right - it would be possible to work one of the turnout frogs, but not both from the same diamond switch)

 

You'll need to decide between a switch on its own (two position, covering the two routes), or something linked to the movement of the turnout tie-bars.     

 

 

Edited March 1, 2023 by Nigelcliffe

[Flying Pig]

26 minutes ago, Nigelcliffe said:

The same switch could also operate the frogs on the two Unifrog turnouts at the same time, turning them into electrofrog. 

 

The polarity of the frogs on the diamond depends on which of the two routes across it is selected, not simply on one of the points being reversed.  If both points are set for the diamond (quite possible with manually operated points) only the operator knows which route is supposed to be live.  So a separate switch for the diamond set by the operator is needed. 

 

 

[Gwiwer]

Insulfrog diamonds are not made in Code 55 but Code 80 can be used at a pinch.  Would it be easier to simply substitute an insulfrog diamond?  My  concern there is that a very small loco with fairly short wheelbase might stall on the dead spot especially at realistically low speeds.  

 

I should perhaps add that I am basically planning a single-loco operation around a single-track loop using DC (not DCC) with the diamond section leading to the shed and a siding.  

Edited March 1, 2023 by Gwiwer

[33C]

Sorry, I thought this thread was for Ribbet counters.....

[Flying Pig]

3 hours ago, Gwiwer said:

Insulfrog diamonds are not made in Code 55 but Code 80 can be used at a pinch.  Would it be easier to simply substitute an insulfrog diamond?  My  concern there is that a very small loco with fairly short wheelbase might stall on the dead spot especially at realistically low speeds.  

 

I should perhaps add that I am basically planning a single-loco operation around a single-track loop using DC (not DCC) with the diamond section leading to the shed and a siding.  

 

An insulfrog diamond would need less wiring and the sidings could be supplied directly from the points with no insulated rail joints required.  However there's another factor because as far as I know, Unifrog points are not self isolating, so the sidings will be live all the time.

 

Could you post a photo of the underneath of one of the Unifrog points?

 

[dasatcopthorne]

There's another way.

 

A rotary switch. 4 pole 3 way. The 3 ways representing straight or the 2 ways over the crossing.

 

The 4 poles operating the 4 differing frog areas or just the two of the crossing if you are using Unifrog turnouts.

 

The switch knob will also indicate the route setting frog wise.

 

Dave.

Edited March 2, 2023 by dasatcopthorne

[Gwiwer]

Trials with an insulfrog diamond prove that current flows as it should but the loco is reluctant to run through nicely.  Put simply it has small wheels and a small wheelbase.  All pickups have been tested and all six wheels pick up as they should but there's just not enough "live" rail for it to run through.  

 

Some more bits have been ordered to see what works best.  A couple of DCC80 switches and GMC-PM1 Seeps with frog switching for the points.  I'll leave the diamond for a moment until the points are sorted.  

[AndyID]

4 hours ago, Gwiwer said:

Trials with an insulfrog diamond prove that current flows as it should but the loco is reluctant to run through nicely.  Put simply it has small wheels and a small wheelbase.  All pickups have been tested and all six wheels pick up as they should but there's just not enough "live" rail for it to run through.  

 

 

Yes, that's the problem with insulfrogs. With a rigid chassis there are really only three points of contact between wheels and track. If the side that only has a single contact is on an insulfrog the motor receives no power.

[DCB]

I would power the Live frog diamond's frogs from a pair of microswitches on the far right point to save additional switching /  the sub miniature ones are pretty small.  I use them for frog polarity witching see photo.

Even without my compression of the photos there are some horrible kinks in that track.