What are 'Hex Frog Juicers'?

[Baby Deltic]

It's a daft name though; might get you a visit from the RSPCA if you order one! ;-)

 

Is that the Royal Society for the Prevention of Cruelty to Amphibians?

[250BOB]

Soluble with switches or relays (depends exact details of how you control the motors) for under £1 per turnout. Or, you can buy frog juicers which make your "cheap" RC servo motors cost more than a Cobalt or Tortoise slow acting motor.

 

If you're happy, use them. I see them as expensive, unnecessary and with unproven medium term consequences due to rail/wheel spark errosion.

 

 

- Nigel

 

Nigel,

Doesn't an auto reverser work on the same principal.??

If it does, then is not the principal of short detection a proven operation?

Bob

[Oldddudders]

There were certainly unworked trailing points in the UK on passenger routes. The Chessington Branch (opened just before the Hitler war) had unworked trailing points where it joined the Up line from Epsom to Waterloo. How do I know? For decades there was a large sign at the junction saying "Unworked Trailing Points"!

And, funnily enough, I've just found this image on the RCTS site which shows those very points http://rcts.org.uk/features/mysteryphotos/show.htm?page=10&serial=173&img=G-187-06 The back of the large notice board I referred to is above the PWay hut.

[Orange Alco]

Drifting slightly off topic As their 'Electrofrog' turnouts in code 75 and code 100 are Peco's premium products for the more advanced modeller who is beyond the 'train set':  it's shame that proper crossing polarity switching contacts are not incorporated into the units and that therefore "Frog Juicers" even have to be considered as an solution.

[Matt]

As others have said already, the generic name for these devices is not "Hex Frog Juicer".

 

The "Hex" version is the 6 way model from the Frog Juicer range.

There is also the "Mono Frog Juicer" and the "Dual Frog Juicer" (which can double up as an Auto-Reverser unit) to complete the line-up of available Frog Juicer products.

 

 

For the OP; details available here (bottom of the page).

.

The hex frog juicer can also be used as up to 3 auto reverse modules by pairing the outputs as detailed in the supplied instructions. This actually makes an economical auto reverse alternative that DOES work with the notoriously sensitive dynamis. I'm using one to run 2 reverse loops plus a diamond crossing.

Matt

[Godders]

 

Soluble with switches or relays (depends exact details of how you control the motors) for under £1 per turnout. Or, you can buy frog juicers which make your "cheap" RC servo motors cost more than a Cobalt or Tortoise slow acting motor.

 

If you're happy, use them. I see them as expensive, unnecessary and with unproven medium term consequences due to rail/wheel spark errosion.

 

Nigel,

Doesn't an auto reverser work on the same principal.??

If it does, then is not the principal of short detection a proven operation?

Bob

 

- Nigel

Hi Bob,

 

You are correct and the juicer can be used as an auto reverser. However Nigel's point is still valid and the reverse loop can be easily wired using a DPDT switch, preferably mechanical synchronised with the turnout.

 

Cheers Godders

[retbsignalman]

Hi!

They're an expensive and largely unnecessary device. They replace a switch to change turnout crossing polarity.

They don't reduce wiring: the Juicer needs a wire from each of the main running rails, and a wire to the turnout crossing (frog). Wiring to a switch attached to turnout motor or operating lever requires an identical number of wires and connections to the same places.

But for some reason some people are seduced by them.

Nigel

 

I'd agree they are indeed expensive, however not that they are largely unnecessary. 

 

They do (or can) reduce wiring (and have done so for me)........I have three, two of which saved me a lot of headache and wiring. One is at a double junction that has three diamond crossings, with two of the routes involving travelling over two of the crossings......this meant that correctly powering the crossing frogs entailed a lot of wires and switching (added problem being that not just the points frogs, but the crossing frogs -sometimes two per route set -  needed to be correctly powered)- even then I could not get it right with routing needs occasionally setting up shorts.

 

Enter a hex frog juicer! Drop a wire from the six frogs on the crossings to said hex frog juicer and hey presto, problem solved! No mass of confusing and difficult wiring, just eight wires (the extra two coming from the bus wires). The second use on my layout is centred around a scissors crossover with a 3 way point thrown in for good measure!

 

The third is in use for points in a yard which do not have motors. I use 'Caboose Industries' hand throws, and had a choice of either running piano wire through tubing to a microswitch at the side if the layout which by experience is not 100% reliable and takes up space. HFJ installed and job done! You soon get the hang of setting routes up to prevent derailments!

 

I'm in disagreement with Nigel on the amount of wiring required. Again I will stand by my statement that they do (or can) reduce the amount of wiring. I see it as follows: Two wires in to the HFJ from the bus - 6 wires out to the frogs, against two wires in to each switching mechanism attached to a point motor and one out to the frog, giving a total of 18 wires for an equivilent number of points served. Thats 8 wires less! 

 

So no, not 'seduced' by them, but bought out of necessity to preserve my sanity, keep my trains running and get shot of lots of wiring.

 

I can also see a use for one if the model is based upon RETB practice, where the exit points from a loop are 'trailed'. Not sure how to set this up yet, but I'm thinking along the lines of using Tortoise motors and an actuating wire strong enough to maintain the 'facing' route set, but weak enough to allow wagon wheels to run through them in the trailing direction without derailment. A tortoise motor would be needed to allow any shunting to take place requiring the points to be moved.

 

In addition to the locations previously mentioned where spring points existed on the Southern, the trailing points at Bickley Jn, where the Up Tonbridge Loop joined the Chatham lines were sprung, which I found surprising given the line speeds of (from memory) 50/70 MPH!

[RFS]

Aren't catch points just the same as unworked trailing points, although only one rail?  And often traversed at speed.

[retbsignalman]

Hi!

Aren't catch points just the same as unworked trailing points, although only one rail?  And often traversed at speed.

 

Not really. Picture a set of points at each end of a passing loop on a single line. As the train approaches the loop it meets the first set of points which are facing the train. It passes over these facing points and enters one of the loops. As it exits the loop it passes over the second set of points, only this time it passes over them in the trailing direction. On a conventionally signalled line, the points would be set manually by the signalman with signals, however on an RETB signalled railway, the points are sprung (using hydraulic pressure) and as the train exits the loop it pushes the point blades across. They return to their normal position under the pressure of the 'spring' after the passage of the train.

 

Catch points are entirely different and were found (mainly) on rising gradients in the days of unfitted and partially fitted trains (fitted as in equipped with brakes controlled by the driver that would automatically apply in the event of the train unexpectedly dividing). As their title suggests, they were designed to 'catch' or derail any run away wagons before they could descend the whole of the incline and cause a collision with a following train. They are as you describe and were also 'sprung'.

 

Trap points are similar to your description, but more commonly found at the exit from sidings where they derail any vehicle that has rolled past the exit signal to protect the main line. They can take the form of a full set of points which may (or may not) lead to a sand drag, or be in the form of just one blade as per the Peco Catch point.

 

Hope this hepls,

 

Graeme  

[Michael Delamar]

If you have an oval layout with fiddle yard and you use them to drive a train out of the fiddle yard. Could you wire it so that the inbound point is automatically set by the outgoing point, so that you drive a train out and around back to the siding it came from?

[Ron Ron Ron]

???????

[Glorious NSE]

For most track designs, a diamond does not exist in total isolation. It is connected to other turnouts (perhaps some distance away) which route the train over the diamond. So, it is usually possible to link the polarity of the diamond to the setting of the adjacent turnouts and/or signals which control the diamond.

Not necessarily the case in the land this product is made in!

[Suzie]

You can get a DCC points decoder with frog switching built in for up to eight points for less than the cost of a hex frog juicer if you don't mind using tiny little servos to operate your points instead of big bulky slow motion motors or snappy solenoids! All that is required is two wires to your DCC feed and up to eight wires to the frogs (one wire to each frog) then plug in the servo motors and away you go.

 

The Frog Juicer has its uses but it should be a last resort when all other routes have been exhausted and not the first.

 

To answer the OP's question - the Frog Juicer is a device that detects that a train has shorted out on a point frog which then reacts to remove the short circuit. If you are happy to have a continuous series of short circuits on your layout every time a train goes over a point then it is OK, but you will have to make sure that you have very beefy wiring and that you do not intend to use decoders that are susceptible to the inevitable voltage spikes that are generated every time a train goes over a frog.

[Crewlisle]

With reference to the reliability or otherwise of polarity switches v hex juicers, on my double junction I have a Peco SL-93 Code 100 Short Insulfrog Crossing which I have converted to a live diamond by replacing the plastic frogs & the small plastic insulators on the outside rails with small soldered rail inserts. On the point giving access across the 'plain route' I have used a Peco PL10 point motor fitted with two Peco PL-13 polarity switches. I worked out the wiring by studying what parts of the diamond required switching. Total cost about £13 - cheap & cheerful!  Is it reliable? I only fitted new points, diamond & switches 6 years ago after the previous ones had been installed for almost 30 years! They have not let me down.

These are the only polarity switches on my DCC exhibition layout 'Crewlisle' layout with a total of 30 points.

[Ron Ron Ron]

With reference to the reliability or otherwise of polarity switches v hex juicers........

 

With due respect, as pointed out on page 1 of this thread, the name of these devices is not "Hex Juicers".

They are "Frog Juicers". The Hex Frog Juicer being just one (6 output size) of the available sizes of Tam Valley Depots range of Frog Juicers.

 

Pedant hat off.

 

Regards

Ron

 

 

.

[Phil S]

If you're happy, use them.   I see them as expensive, unnecessary and with unproven medium term consequences due to rail/wheel spark errosion.

 

Phil: As Massoth (manufacturers of the electronics for LGB in the past, and G Scale in the present, where 'large currents' can mean 10A normal maxima, and more during a 'short') have demonstated with their latest solid-state auto reverser, which uses 'pre-detection' to PRESET the required polarity of an auto-reverse section, the same simple principle can be applied to Frog-Polarity Switching with pre-detection by track occupation, to set the correct polarity.   Especially as there are some examples where there is NO associated point movement to determine  a Diamond Crossing Frog Polarity - detecting a train on either of the pairs of tracks approaching the crossing can be used to preset the frog polarity - so that it is always correct, and with no short or mechanical interlinking.

Detection can either be, as with the Massoth AR, or a metal wheel and a small 'detector' section of track, or an independant OPTICAL detector such as the Hector IR detector from MERG (or a Heathcote module) to preset the polarity to match the movement.      The 'auto-reverse'/short  detection circuitry is then only used as a failsafe backup system.

[298]

I would say I was a good operator, in the same way the majority of UK motorists would say they were good drivers. But after about 4 solid hours at an exhibition, having to endure layout gremlins and the inane drivel that some punters think you have to hear, I'd admit that standards do slipans my attention wavers a bit. And the first thing I start doing is to run towards facing points, causing a short. So a Frog juicer would at least give me more time to react in that situation, and is more prototypical as a lazy crew wouldn't want to walk too far, and would run up to the frog before someone jumped off to throw the turnout.

 

The new layout also features an electrofrog diamond, and it looks impossible to wire it through relying on linking it to pointwork frogs without conflicting moves creating a short, so a Frog juicer is ideal.

[Junctionmad]

They are good for live frog diamonds that for sure 

[Junctionmad]

You can get a DCC points decoder with frog switching built in for up to eight points for less than the cost of a hex frog juicer if you don't mind using tiny little servos to operate your points instead of big bulky slow motion motors or snappy solenoids! All that is required is two wires to your DCC feed and up to eight wires to the frogs (one wire to each frog) then plug in the servo motors and away you go.

 

The Frog Juicer has its uses but it should be a last resort when all other routes have been exhausted and not the first.

 

To answer the OP's question - the Frog Juicer is a device that detects that a train has shorted out on a point frog which then reacts to remove the short circuit. If you are happy to have a continuous series of short circuits on your layout every time a train goes over a point then it is OK, but you will have to make sure that you have very beefy wiring and that you do not intend to use decoders that are susceptible to the inevitable voltage spikes that are generated every time a train goes over a frog.

 

As a EE, I would have to argue with some of the points raised here,   Firstly all wiring on a DCC layout should be capable of handling the DCC fault current , before the booster cuts out.  Frog juicers, ( based on reading the manual) trip at around 1.7 - 2Amps and are typically well below the full DCC short  circuit current.  Hence there should be no upgrade to any wiring to handle " frog juicing "

 

a well designed frog juicer should not produce any " spikes " , there are already lots of " spikes" as your wheels traverse a typical layout. Juicing doesn't  add to this.

 

To suggest  "but it should be a last resort when all other routes have been exhausted and not the first." is akin to Luddism, or suggesting that you should have a carburated engine instead of a fuel injected one. 

 

" Frog juicing" circuits are extremely easy to make up if you have any electronics knowledge. 

 

Yes you can so it the traditional way, but for DCC , its a good viable non mechanical alternative 

 

You do have to be careful where engines span multiple frogs in complex point work as " Juicers  " can be presented with impossible solutions 

[Suzie]

The key word here is 'Should'. The manual might say that it starts switching at 1.7A, but that does not mean that the current does not build up to more than that before the switching is complete and the spike is generated.

 

I would suggest that using the juicer is Luddism rather than using a more suitable switching alternative. Just because the juicer costs more and uses semiconductor switches out of necessity does not make it a more suitable solution.

[Junctionmad]

The key word here is 'Should'. The manual might say that it starts switching at 1.7A, but that does not mean that the current does not build up to more than that before the switching is complete and the spike is generated.

 

I would suggest that using the juicer is Luddism rather than using a more suitable switching alternative. Just because the juicer costs more and uses semiconductor switches out of necessity does not make it a more suitable solution.

I'm not sure what you are basing your comments on , if the current builds up typically the booster will trip , so juicers must complete the switch over before that. At no point should the current exceed the wiring.

 

Dcc is a fast edge switching system anyway. I'm not sure how you perceive " spikes " are an issue, and clearly they are not

 

I can't see the objection to the solution , in fact in reality it allows better realism.

[Andy Reichert]

As a EE, I would have to argue with some of the points raised here,   Firstly all wiring on a DCC layout should be capable of handling the DCC fault current , before the booster cuts out.  Frog juicers, ( based on reading the manual) trip at around 1.7 - 2Amps and are typically well below the full DCC short  circuit current.  Hence there should be no upgrade to any wiring to handle " frog juicing "

 

a well designed frog juicer should not produce any " spikes " , there are already lots of " spikes" as your wheels traverse a typical layout. Juicing doesn't  add to this.

 

To suggest  "but it should be a last resort when all other routes have been exhausted and not the first." is akin to Luddism, or suggesting that you should have a carburated engine instead of a fuel injected one. 

 

" Frog juicing" circuits are extremely easy to make up if you have any electronics knowledge. 

 

Yes you can so it the traditional way, but for DCC , its a good viable non mechanical alternative 

 

You do have to be careful where engines span multiple frogs in complex point work as " Juicers  " can be presented with impossible solutions 

 

Getting the same results with solid traditional technology for far less money (e.g. a relay) isn't Luddism, it's Engineering.  

 

Andy (EE)

[Junctionmad]

Getting the same results with solid traditional technology for far less money (e.g. a relay) isn't Luddism, it's Engineering.  

 

Andy (EE)

I agree that the current offerings are expensive for what they do. And as an EE, I'm sure like me you can knock up a circuit to do it for a few bob.

 

I wasn't arguing price , I was merely countering a perspective here that using automatic frog switching is somehow inferior

[The Bigbee Line]

A couple of observations from this thread:

 

As a person with basic knowledge only on electronics - It appears that a device to change polarity (switch on seeing a short) can be cheaply made. - Can someone suggest a circuit that I could build.  I'd gladly have a go.

 

As a potential user - It offers the chance to save time in getting a layout up and running, i.e. just connect the wires from the live frogs and two wires from the bus and your away.  Much quicker than fitting switches of some kind.  If you don't like the layout there isn't a load of wasted time in wiring etc.

 

Regarding DC v DCC - I am currently building a small shunting layout.  It has 6 turnouts specifically to use a hex frog juicer that is in a safe place (No idea where at the moment).  When I test run with DC I'll try small locomotives with the frogs dead.  If they stall, I will use an 0-6-0 tender loco with tender pick ups, or fit an 03 with a runner wagon specifically fitted with additional pick ups.

 

STUPID QUESTION - Will a 'stay alive' capacitor inprove the running of a DCC locomotive when running on DC (told you my knowledge was basic)

[Phil S]

'The Bigbee Line' asked:  (snipped)...

 

As a person with basic knowledge only on electronics - It appears that a device to change polarity (switch on seeing a short) can be cheaply made. - Can someone suggest a circuit that I could build.  I'd gladly have a go.

As a potential user - It offers the chance to save time in getting a layout up and running, i.e. just connect the wires from the live frogs and two wires from the bus and your away.  Much quicker than fitting switches of some kind.  If you don't like the layout there isn't a load of wasted time in wiring etc.

 

I mentioned in another thread yesterday that LDT make a kit and ready-built module of an 'autoreverser' which includes PRE-SENSING of which end the loco is at, and therefore PRE-SETS the polarity in advance of a short circuit occuring   I first knew (and bought) a commercial version of this when Massoth (electronics for G Scale /LGB) released such an Auto-reverser a year os so ago - avoiding 10A shorts!  I have now ordered 3 of the LDT kits to replace my remaining short-based reversers for 00/H0..  

The 'pre sensing' can be off track occupation, but can equally be set by other detectors or switches ...for instance,  IR light sensors on each leg of a diamond crossing - with the 'short-reverse built in as a backup in case the optical or other detection has failed.

 

Where passage through a Reverse Loop section is provided with Colour Light Signals on entry and exit - these can be linked in to either control, or indicate the result of, the polarity switching of the track .... if green, then the polarity is correct to cross that boundary ../. if correct polarity, then make the light green.  Simple D-type latches  (made form 2 NAND gates or 1/2 a 'Quad NAND gate IC'  can be set and reset from the oter detectors... first come, first served, and given the green light .... then easy to operate a relay (and no response speed worry with pre-selection)

 

 

Those who advocate against 'motionless switching' continually ignore that NOT ALL routing practice has a mechanical route setting associated with it - eg a level-crossing of 2 tracks from different companies (as used to occur in the UK, and still does in at least one place in sweden) and  TRAM operation with sprung points crossing junctions etc etc etc.

 

STUPID QUESTION - Will a 'stay alive' capacitor inprove the running of a DCC locomotive when running on DC (told you my knowledge was basic)

Phil: Not a stupid question - Yes, to some extent! .... As you realise, when used on DC, a 'base level' of voltage is required to power the Processor, and above that voltage, the speed is proportionally increased from 0 speed (at say 5V on track) to full speed at ' nominally 12V' on track.

The Stay Alive capacitor is on the Rectified Internal Power Supply Side of the decoder ....and when the  loco is being driven at 'high speed' the capacitir will have a chance to charge up above the 5V level, possibly reaching 'full charge' if you are running fast!   Any momentary loss of power supply, such as over dead-frog points or dirt on track, the capacitor will maintain control of the processor ... so it will not have to 'restart' and 're analyse' the situation each time ... therefore aiding continuity of operation.   As the loco will have been moving, with inertia, at this time, you may notice little difference in visible motion .... but the closer your are to the 'zero speed' at circa 5V, the less the capacitor reserve, and so the less protection ....UNLIKE the dcc situation, where the ful track voltage is 'always' available, and therefore the stored charge is always at is peak... allowing maybe  a few seconds of operation. So you are likely to get 'a bit of extra protection' over a dead section, but not the sort of 2 seconds protection which some provide.