Point decoders and frog switching

[TomJ]

After years of failing to get Peco micro switches to work reliably when I was on DC I was delighted to discover frog juicers when I switched to DCC! Using them alongside DCCConcepts solenoid decoders worked perfectly. 
 

Now 10yrs later I discover than the basic decoder has been replaced with a slightly more an advanced that seems to include frog switching - the ADS-8fs. 
It would be cheaper to use this rather than buy a cheaper decoder and a frog juicer. Is there any disadvantage to this plan other than extra wiring (seems like you need a track feed for every point unlike the juicer. And does it work reliably?

 

Any advice and tips gratefully received!

[WIMorrison]

I would always have the polarity switching of a frog done by the actual motor as that way it is guaranteed to be in sync with the position of the turnout blades.

[peterm1]

3 hours ago, WIMorrison said:

I would always have the polarity switching of a frog done by the actual motor as that way it is guaranteed to be in sync with the position of the turnout blades.

Yep. I've never found the need to use frog juicers. An answer to a problem that doesn't exist. Tortoise for me every time.

[Pete the Elaner]

8 minutes ago, peterm1 said:

Yep. I've never found the need to use frog juicers. An answer to a problem that doesn't exist. Tortoise for me every time.

 

Not quite.

Frog juicers are a solution to cope with operator errors (when you forget to throw a point).

You could argue that the errors are bad operating practise & we all try to avoid them, but they do happen.

[RFS]

21 minutes ago, Pete the Elaner said:

 

Not quite.

Frog juicers are a solution to cope with operator errors (when you forget to throw a point).

You could argue that the errors are bad operating practise & we all try to avoid them, but they do happen.

 

So how does this stop the train from derailing on the point?

[WIMorrison]

22 minutes ago, Pete the Elaner said:

 

Not quite.

Frog juicers are a solution to cope with operator errors (when you forget to throw a point).

You could argue that the errors are bad operating practise & we all try to avoid them, but they do happen.

 

Not sure how a frog juicer prevents a short circuit when you run into a turnout set the wrong way.

[Pete the Elaner]

14 minutes ago, RFS said:

 

So how does this stop the train from derailing on the point?

Doesn't.

But it doesn't stop anything else & that is the idea. If the derailment is in the fiddle yard, anything happening in the scenic section is totally unaffected.

[Pete the Elaner]

14 minutes ago, WIMorrison said:

 

Not sure how a frog juicer prevents a short circuit when you run into a turnout set the wrong way.

 

From what I have seen you post in the past, I know full well you know how it works, so I guess you are just prompting me to explain?

 

There will be a short, but the the Frog juicer switches the polarity so quickly to rectify it that the command station safety cut out will not detect the issue & any locos moving and/or making sound will also carry on without any interruption.

 

I did not like the idea of using one until I operated a layout which used them. They don't expose errors like switching the frog with the point will do.

[WIMorrison]

surely you will still get a short when a loco covers the isolation gap between between the frog and the track when the blades are set against the train - unless the 'frog juicer' somehow cuts the power completely, thus totally isolating the frog when the short remains. 

 

To make it work as you suggest requires the frog to be totally isolated which will require modifying the turnouts when they are not supplied with isolation cuts (and that is fraught with problems) - hence it is not done for many turnouts. 

 

 

Edited February 16 by WIMorrison
spelling

[Penrhos1920]

5 hours ago, peterm1 said:

Yep. I've never found the need to use frog juicers. An answer to a problem that doesn't exist. Tortoise for me every time.

 

So how do you switch the 2 frogs on a diamond, since it has no blades to switch?

[TomJ]

So if I’m honest I don’t fully follow the discussion above!!! I’m a simple soul who doesn’t fully understand wiring or DCC. 
I model in N gauge and use Peco solenoids. I never managed to get their micro switches to work reliably so the frog juicer seemed like the answer to my prayers!

 

Given all this what I’m trying to work out is what is the best way to switch the frog polarity on my new layout. I’m ruling out micro switches. So should I go for frog juicer or use the switching facility on thr DCCConcepts decoder - I’ll admit I don’t really know how either work!

[RFS]

1 hour ago, Penrhos1920 said:

 

So how do you switch the 2 frogs on a diamond, since it has no blades to switch?

 

In most instances via the switches on the points that control the path over the diamond crossing. I have several crossings on my layout wired like that with Tortoise motors. For example, with a crossover using two points, each point switch controls its own frog plus the diamond frog furthest away as both require the same polarity. Only thing to remember is that, if a train is set to traverse the centre road, the points must not be set for the crossover, but that is normal prototype practice anyway. 

[Pete the Elaner]

44 minutes ago, TomJ said:

So if I’m honest I don’t fully follow the discussion above!!! I’m a simple soul who doesn’t fully understand wiring or DCC. 
I model in N gauge and use Peco solenoids. I never managed to get their micro switches to work reliably so the frog juicer seemed like the answer to my prayers!

 

Given all this what I’m trying to work out is what is the best way to switch the frog polarity on my new layout. I’m ruling out micro switches. So should I go for frog juicer or use the switching facility on thr DCCConcepts decoder - I’ll admit I don’t really know how either work!

 

The built in switch is effectively like a micro switch, but no alignment is necessary. Once wired in, the frog polarity will switch when the point throws. This provides an advantage that you can wire the frog back to the control panel to show which way the point is set.

 

Frog juicers are reactive. When you throw the point, the frog polarity is unaffected so when a loco straddles the frog section, this causes a short circuit. The juicer detects this & flips the polarity (strictly phase, but polarity is easier to visualise). It does this so quickly that any trains in the section & the command station are unaffected.

Being of the mindset that short circuits are bad & should be avoided, I thought it was a complete bodge & a terrible idea. Having seen it in operation, it seems to work well.

[TomJ]

Thanks for explaining. So if the decoder switch is basically a micro switch but without the alignment issue then it ought to be more reliable than the old fashioned use of switches? If so it would seem daft to buy a decoder with that option (because I like the DCCConcepts products) and then pay for a juicer to basically do the same thing as well

[peterm1]

1 hour ago, RFS said:

 

In most instances via the switches on the points that control the path over the diamond crossing. I have several crossings on my layout wired like that with Tortoise motors. For example, with a crossover using two points, each point switch controls its own frog plus the diamond frog furthest away as both require the same polarity. Only thing to remember is that, if a train is set to traverse the centre road, the points must not be set for the crossover, but that is normal prototype practice anyway. 

That's how I do it for diamonds and slips.

[peterm1]

2 hours ago, Penrhos1920 said:

 

So how do you switch the 2 frogs on a diamond, since it has no blades to switch?

RFS has given the answer. 🙂

[Nigelcliffe]

33 minutes ago, TomJ said:

Thanks for explaining. So if the decoder switch is basically a micro switch but without the alignment issue then it ought to be more reliable than the old fashioned use of switches? If so it would seem daft to buy a decoder with that option (because I like the DCCConcepts products) and then pay for a juicer to basically do the same thing as well

 

It's daft to pay twice.     

The "switch" in the DCC Concepts device will be electronic, or a relay operated by the electronics.   It won't be a micro-switch with a movement to operate it.  

 

The only possible issue against using the DCC Concepts device might be "switch timing".    Whether this matters depends on "which turnouts", "which maker" and how they are setup.   

For example, Peco N gauge electrofrogs (as supplied, un-modified) don't have any isolation between the blades and the frog.   So, if switching the frog by an external switch (DCC Concepts in this case), it needs to change at the same time, precisely, as the blades move.   If it is "late" or "early", a short circuit occurs as one power connection is via the blades, and a different one via the switch.   

 

Whereas many (most?) Peco OO electrofrogs have the blades separated from the frog, so there is no electrical connection to worry about, and no timing issue.  

 

 

 

 

- Nigel

[AndrueC]

On 16/02/2024 at 21:04, RFS said:

In most instances via the switches on the points that control the path over the diamond crossing. I have several crossings on my layout wired like that with Tortoise motors. For example, with a crossover using two points, each point switch controls its own frog plus the diamond frog furthest away as both require the same polarity. Only thing to remember is that, if a train is set to traverse the centre road, the points must not be set for the crossover, but that is normal prototype practice anyway. 

Yes, if the diamond can be set to allow trains from both directions to cross over (as used in a figure of eight configuration) then a juicer for each frog is the most practical solution.

[peterm1]

Sorry Andrue, but I really don't think using a frog juicer is the answer. It might seem to be complicated to use the switches in the stall motors, but it's not.

[AndrueC]

2 hours ago, peterm1 said:

Sorry Andrue, but I really don't think using a frog juicer is the answer. It might seem to be complicated to use the switches in the stall motors, but it's not.

How do you do that when trains can pass through the diamond from either direction without any turnout motors changing? My crossing has only two modes - both lines straight through or both lines crossing. The latter requires that the frog polarities be changed by something unconnected to the turnouts.

[Vecchio]

Having had problems with switches closing too early or opening too late I scrapped them all and use frog juicers only. Works a treat. Donnersbachkogel uses approximately 40 of them. No issues so far. Layout in use since beginning of 2020.

[KingEdwardII]

6 minutes ago, Vecchio said:

switches closing too early or opening too late

Switches built into point motors like the MTB MP1s don't have this problem. They are constructed to work in tandem with the motion of the motor and enable the frog polarity to match the position of the turnout tie bar. I have no problems with my 30+ MP1s.

 

Yours, Mike.

[WIMorrison]

6 minutes ago, KingEdwardII said:

Switches built into point motors like the MTB MP1s don't have this problem. They are constructed to work in tandem with the motion of the motor and enable the frog polarity to match the position of the turnout tie bar. I have no problems with my 30+ MP1s.

 

Yours, Mike.

 

Mike,

 

If the MP1 are not correctly aligned to the tie-bar, or the movement is slightly more in one direction compared to the other, then it is possible for the blade operation and polarity switching timing to be out resulting a brief short, but easily cured by aligning correctly.

[Vecchio]

38 minutes ago, KingEdwardII said:

Switches built into point motors like the MTB MP1s don't have this problem. They are constructed to work in tandem with the motion of the motor and enable the frog polarity to match the position of the turnout tie bar. I have no problems with my 30+ MP1s.

 

Yours, Mike.

Just for your information - I use RC servos, an I used micro switches actuated by the servo arm. 

[KingEdwardII]

38 minutes ago, WIMorrison said:

If the MP1 are not correctly aligned to the tie-bar,

True, but if that is the case, you will likely have a bigger problem of the switch blades not being fully home resulting in derailments. I spend time & effort when installing the motors to ensure correct alignment to so that this problem does not occur.

 

Yours, Mike.