AndyID Posted November 3, 2015 Share Posted November 3, 2015 Any resemblance to the South African flag is purely coincidental. A slight variation on the insulated frog. The green bits are insulators. Most important are the insulators on the insides of the wing rails. They are positioned so that they prevent the backs of wheels making contact with the wings, but they do not extend to the top of the rails. This allows the wheel treads to maintain contact as they pass through the crossing. Link to post Share on other sites More sharing options...
RMweb Gold 2mmMark Posted November 3, 2015 RMweb Gold Share Posted November 3, 2015 This seems more effort to make than an all-metal crossing and wiring in a switch. Link to post Share on other sites More sharing options...
PatB Posted November 3, 2015 Share Posted November 3, 2015 Would you not still get a short as a wheel tread bridged the V-rails just beyond the insulated nose? Link to post Share on other sites More sharing options...
AndyID Posted November 3, 2015 Author Share Posted November 3, 2015 This seems more effort to make than an all-metal crossing and wiring in a switch. Thank you for your support. Link to post Share on other sites More sharing options...
AndyID Posted November 3, 2015 Author Share Posted November 3, 2015 Would you not still get a short as a wheel tread bridged the V-rails just beyond the insulated nose? Not if the wheels are coned, and they usually are. Link to post Share on other sites More sharing options...
Grovenor Posted November 3, 2015 Share Posted November 3, 2015 Surely this is very similar to what Peco have been doing for years, and shorts across the two V-rails do occur with some types of wheel. The lining on the wing rails is a new idea, to me anyway, and should not be to difficult to implement. Regards Link to post Share on other sites More sharing options...
AndyID Posted November 3, 2015 Author Share Posted November 3, 2015 Surely this is very similar to what Peco have been doing for years, and shorts across the two V-rails do occur with some types of wheel. The lining on the wing rails is a new idea, to me anyway, and should not be to difficult to implement. Regards If the wheels are coned (I know some Lima wheels are not coned) and the rails in the V are at the correct height, there is no reason why they would short, but it does demand a strict control on the heights of the rails in the V. "Insulfrog" points don't have metal wing rails, and that greatly extends the length of the "dead" section. The major benefit of switched frogs is that the wheel treads can collect current from the wing rails as they pass through the crossing. Insulating the insides of the wing rails in this arrangement has the same effect (or at least, it should! - I've never actually tried it.) Link to post Share on other sites More sharing options...
RMweb Gold martin_wynne Posted November 3, 2015 RMweb Gold Share Posted November 3, 2015 Those reduced ends on the point and splice rails are going to be very difficult to make with ordinary rail section. Peco can do it because they don't use ordinary rail section in their turnouts, they use a special flat-bottom section without a web. This allows it to be insert moulded in the plastic mould tool. I can't help feeling that dabbing a relay under the baseboard with the glue gun, linking it to the crossing with a wire, and slaving it across the point motor, is 10 times easier than making those rails in your diagram. However you make them, they are going to need a wire attached somewhere. Your design needs 4 wires, an ordinary soldered crossing assembly needs just 1 wire. Martin. Link to post Share on other sites More sharing options...
AndyID Posted November 3, 2015 Author Share Posted November 3, 2015 Hi Martin, You could be right, but I'm interested to see if it's possible. Switched frogs create problems on DCC layouts. This might be one solution. Cheers! Andy Link to post Share on other sites More sharing options...
Suzie Posted November 3, 2015 Share Posted November 3, 2015 ...Switched frogs create problems on DCC layouts... How? Link to post Share on other sites More sharing options...
Grovenor Posted November 3, 2015 Share Posted November 3, 2015 How? By careless driving! Rgds Link to post Share on other sites More sharing options...
RMweb Gold Phil Bullock Posted November 3, 2015 RMweb Gold Share Posted November 3, 2015 OK - I am NOT going to be the first to mention frog juicers..... Phil Link to post Share on other sites More sharing options...
RMweb Premium ColinK Posted November 3, 2015 RMweb Premium Share Posted November 3, 2015 Its always worth thinking of new ways of doing things. Hope you'll make one and let us know how you get on. Link to post Share on other sites More sharing options...
AndyID Posted November 3, 2015 Author Share Posted November 3, 2015 How? Hi Suzie, If you drive into a trailing point with a switched frog that's set the wrong way, the locomotive short circuits the track and the locomotive stops. That's not a bad thing on a DC layout, but with DCC, everything else stops too. That's not a good thing, particularly at an exhibition Cheers! Andy Link to post Share on other sites More sharing options...
AndyID Posted November 3, 2015 Author Share Posted November 3, 2015 OK - I am NOT going to be the first to mention frog juicers..... Phil Hi Phil, Thanks for not bringing that up Yes, juicers will solve that problem too. A bit spendy though ($12 a pop here) and then you still have to wire them up. Cheers! Andy Link to post Share on other sites More sharing options...
RMweb Gold martin_wynne Posted November 3, 2015 RMweb Gold Share Posted November 3, 2015 If you drive into a trailing point with a switched frog that's set the wrong way, the locomotive short circuits the track and the locomotive stops. That's not a bad thing on a DC layout, but with DCC, everything else stops too. That's not a good thing, particularly at an exhibition Feeding the crossing (frog) through a 12V 21W car flasher bulb between the polarity switch and the crossing (frog) would prevent that. Assuming the power supply's current-fold-back is set above 2amps. They are not expensive, and they light up to indicate what's happened. A photodiode could be taped onto it if you want a digital signal of the event. edit: 10 for £2. http://www.ebay.co.uk/itm/10x-RW382-Bulb-12v-21W-P21W-BA15s-Stop-and-Flasher-Bulb-/280927658012 Martin. Link to post Share on other sites More sharing options...
AndyID Posted November 3, 2015 Author Share Posted November 3, 2015 Feeding the crossing (frog) through a 12V 21W car flasher bulb between the polarity switch and the crossing (frog) would prevent that. Assuming the power supply's current-fold-back is set above 2amps. They are not expensive, and they light up to indicate what's happened. A photodiode could be taped onto it if you want a digital signal of the event. edit: 10 for £2. http://www.ebay.co.uk/itm/10x-RW382-Bulb-12v-21W-P21W-BA15s-Stop-and-Flasher-Bulb-/280927658012 Martin. You stole my idea! That's how I protect my DC controllers (Actually, I think I pinched it from Hornby-Dublo) Yes, that would work too. In fact, an enterprising person could pot them in a box and strap a couple of LEDs across the bulb (for marketing reasons), then sell them on Ebay for $8 a pop Link to post Share on other sites More sharing options...
RMweb Gold RFS Posted November 3, 2015 RMweb Gold Share Posted November 3, 2015 AndyID, on 04 Nov 2015 - 06:46, said:AndyID, on 04 Nov 2015 - 06:46, said: Hi Suzie, If you drive into a trailing point with a switched frog that's set the wrong way, the locomotive short circuits the track and the locomotive stops. That's not a bad thing on a DC layout, but with DCC, everything else stops too. That's not a good thing, particularly at an exhibition Cheers! Andy But if the frog polarity set by the point-controlled switch is wrong, then that also means the blades are in the wrong position. So if you avoid the short then the loco is going to derail on the turnout anyway. Much better that it stops short on the frog. Same argument with a frog-juicer: if you drive the train into a trailing point set the wrong way, the juicer will prevent the short on the frog but cannot prevent the derailment. And all the above assumes the loco is at the front of the train .... Link to post Share on other sites More sharing options...
RMweb Gold martin_wynne Posted November 3, 2015 RMweb Gold Share Posted November 3, 2015 Much better that it stops short on the frog. Same argument with a frog-juicer: if you drive the train into a trailing point set the wrong way, the juicer will prevent the short on the frog but cannot prevent the derailment But DCC users have decided that the derailment is preferable to a short-circuit which brings the entire layout to a halt. My view is that bringing the entire layout to a halt would be a good way to train the operator not to do it again. Martin. Link to post Share on other sites More sharing options...
Suzie Posted November 3, 2015 Share Posted November 3, 2015 Hi Suzie, If you drive into a trailing point with a switched frog that's set the wrong way, the locomotive short circuits the track and the locomotive stops. That's not a bad thing on a DC layout, but with DCC, everything else stops too. That's not a good thing, particularly at an exhibition Cheers! Andy This is not a fault with the frog, but a fault with the driving! That said there are a few ways of mitigating it if it is acceptable on your layout to use the points as if they are sprung. Some have been mentioned already (Frog Juicer and current limiting bulbs) but using an electronic circuit breaker to feed all the frogs is a better option still. It might appear expensive, but a PSX-2 is cheaper than a layout full of Frog Juicers and it does save a lot of work, and due to the low average current draw across all the frogs you will most likely only need one pair per layout. Using a circuit breaker gets around the high impedance issue with the bulbs and the frequent shorts that occur when a Frog Juicer is working normally. The title of this thread is a question, and the answer is a resounding yes. If building your own track, don't go to the effort of trying to recreate Peco Streamline Insulfrog - which has proved to be so troublesome that in practice needs to be wired as if it is live frog anyway for DCC use. I can see that this method of construction may have some value to the wiring phobic DC operator and they will value your contribution which can eliminate the need for external power routing but it is not suited to DCC. Link to post Share on other sites More sharing options...
AndyID Posted November 3, 2015 Author Share Posted November 3, 2015 But if the frog polarity set by the point-controlled switch is wrong, then that also means the blades are in the wrong position. So if you avoid the short then the loco is going to derail on the turnout anyway. Much better that it stops short on the frog. Same argument with a frog-juicer: if you drive the train into a trailing point set the wrong way, the juicer will prevent the short on the frog but cannot prevent the derailment. And all the above assumes the loco is at the front of the train .... Hi RFS, Yes. That's correct. On a DC layout it's probably better that the locomotive stops before it derails, but on large DCC layouts with several operators the whole shooting match will stop dead. That's bad enough on a club night, but it's not a pretty sight at an exhibition, especially if all the operators utter a naughty word simultaneously. Personally, I've never attempted to drive over a point that's set the wrong way, so I don't know what all the fuss is about (Looks like Martin beat me to it.) Cheers! Andy Link to post Share on other sites More sharing options...
Junctionmad Posted November 3, 2015 Share Posted November 3, 2015 Any big DCC layout , especially an exhibition one , should have district cutoffs to limit system wide shorts. Link to post Share on other sites More sharing options...
AndyID Posted November 3, 2015 Author Share Posted November 3, 2015 Using a circuit breaker gets around the high impedance issue with the bulbs Hi Suzie, I'm not sure 0.7 ohms is exactly a "high impedance". Anyway, if it turned out that isolated frogs could be made to work just as well as switched frogs (and I'm not saying they can) what would be the downside? I suppose the juicer manufacturers might not be too happy, but I think that would be about it. Cheers! Andy EDIT: Speeling mistake Link to post Share on other sites More sharing options...
AndyID Posted November 3, 2015 Author Share Posted November 3, 2015 Any big DCC layout , especially an exhibition one , should have district cutoffs to limit system wide shorts. Hi JM, I would hope so, I wonder how many of them actually do. Cheers! Andy Link to post Share on other sites More sharing options...
autocoach Posted November 3, 2015 Share Posted November 3, 2015 Makes "dead rail" schemes even more desirable. About 4 years and this topic will be an anachronism. For now just add 2 second super caps or keep alives to rail powered engines or other current drawing rolling stock and isolate the whole turnout. Avoid stopping on turnouts. Link to post Share on other sites More sharing options...
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