shortliner Posted March 24, 2019 Share Posted March 24, 2019 (edited) Quote from a post on FB regarding installing magnets for uncoupling Kadees instead of their in-track magnets Can someone please tell me how to make the "cutting key" by inserting a momentary contact, push-button into a DC track feed - I can't, for the life of me, see how it should be wired (A circuit diagram would be fine - all my tries are non-workable!!!) I have a feeling that the solution (when pointed out) is going to be blindingly obvious, but at the moment I can't see it! Edited March 24, 2019 by shortliner Link to post Share on other sites More sharing options...
wasdavetheroad Posted March 24, 2019 Share Posted March 24, 2019 Is the power you are trying to 'cut' energising the magnet? If so a 'momentary action 'cutting key' will switch the magnet off for a fraction of a second, but why would that jog the engine? Or if the loco is DC is it still moving when crossing the coupling? If so a 'cutting key' briefly reversing the positive and negative would jolt the engine? Link to post Share on other sites More sharing options...
wasdavetheroad Posted March 24, 2019 Share Posted March 24, 2019 this might work. It is a DPDT switch Link to post Share on other sites More sharing options...
RMweb Premium dhjgreen Posted March 24, 2019 RMweb Premium Share Posted March 24, 2019 Tried a CAD package Pah. Can you follow this sketch? Link to post Share on other sites More sharing options...
shortliner Posted March 24, 2019 Author Share Posted March 24, 2019 (edited) Wasdavetheroad, the magnets are ordinary cylindrical rare-earth magnets 3/4 each side with tops on one side N and the other side S, set under the rails - the loco/train stops with the couplers over them and the magnetism opens the couplers - but it cannot do this if the couplers are under tension - this is why you see Kadee fitted trains do a little "jiggle" back and forth to take the tension off the couplings. What the "Cutting key" presumably does is that by pressing the button, it momentarily reverses the track power and causes the "Jiggle". Your suggestion might work if it is possible to get a momentary contact DPDT button. I was looking at feeding the track via a press button, but the power would need to be broken momentarily before the reversing can take place. Edited March 24, 2019 by shortliner Link to post Share on other sites More sharing options...
RMweb Premium dhjgreen Posted March 24, 2019 RMweb Premium Share Posted March 24, 2019 See my sketch above; both push button and toggle momentary dpdt are available. 1 Link to post Share on other sites More sharing options...
shortliner Posted March 24, 2019 Author Share Posted March 24, 2019 (edited) DHGreen - I hadn't even thought of doing it that way - very clever - need to think on it, and hunt for a momentary push button , any suggestions where I might get one - it will have to be on line as I'm in the Far North! Edited March 24, 2019 by shortliner Link to post Share on other sites More sharing options...
RMweb Premium dhjgreen Posted March 24, 2019 RMweb Premium Share Posted March 24, 2019 2 minutes ago, shortliner said: DHGreen - I hadn't even thought of doing it that way - very clever - need to think on it! If you try this, you need to be very pedantic about the wiring. The circuit shows the switch in the relaxed position and the loco section of track will be the same polarity at those either side of it. The wrong way round and there will be a short as the loco passes over the IRJs. Easy fixed by swapping the wires but will rely on the protection of your controller. Good luck Link to post Share on other sites More sharing options...
shortliner Posted March 24, 2019 Author Share Posted March 24, 2019 Pedantic wiring is No problem - The problem lay (lies) in getting my head around the requirement - which you may very well have solved for me - many thanks - just need to sort out the push button supplier Link to post Share on other sites More sharing options...
shortliner Posted March 24, 2019 Author Share Posted March 24, 2019 (edited) Supplier sorted - RS components had exactly what I need Edited March 24, 2019 by shortliner 1 1 Link to post Share on other sites More sharing options...
ejstubbs Posted March 24, 2019 Share Posted March 24, 2019 (edited) 2 hours ago, dhjgreen said: If you try this, you need to be very pedantic about the wiring. The circuit shows the switch in the relaxed position and the loco section of track will be the same polarity at those either side of it. The wrong way round and there will be a short as the loco passes over the IRJs. Easy fixed by swapping the wires but will rely on the protection of your controller. Good luck Surely, if it's DC, you don't need the IRJs and all that malarky*? Just put the momentary reversal switch on the output side of the controller, before it goes anywhere near the track. Then there's no risk of shorts due to the loco bridging the gap between the normal and reversed polarity sections. * Unless, maybe, you're using common return? But let's not go there again... Edited March 24, 2019 by ejstubbs 1 1 Link to post Share on other sites More sharing options...
wasdavetheroad Posted March 24, 2019 Share Posted March 24, 2019 7 hours ago, shortliner said: Wasdavetheroad, the magnets are ordinary cylindrical rare-earth magnets 3/4 each side with tops on one side N and the other side S, set under the rails - the loco/train stops with the couplers over them and the magnetism opens the couplers - but it cannot do this if the couplers are under tension - this is why you see Kadee fitted trains do a little "jiggle" back and forth to take the tension off the couplings. What the "Cutting key" presumably does is that by pressing the button, it momentarily reverses the track power and causes the "Jiggle". Your suggestion might work if it is possible to get a momentary contact DPDT button. I was looking at feeding the track via a press button, but the power would need to be broken momentarily before the reversing can take place. Confused, if the loco is stopped there is not any track power as there is zero V, in which case reversing the polarity won't do anything until you apply power? Or do you turn the controller knob until the loco stops but don't turn it to 'zero' Link to post Share on other sites More sharing options...
RMweb Premium dhjgreen Posted March 25, 2019 RMweb Premium Share Posted March 25, 2019 14 hours ago, ejstubbs said: Surely, if it's DC, you don't need the IRJs and all that malarky*? Just put the momentary reversal switch on the output side of the controller, before it goes anywhere near the track. Then there's no risk of shorts due to the loco bridging the gap between the normal and reversed polarity sections. * Unless, maybe, you're using common return? But let's not go there again... Yes but with multiple controllers and cab control, this could be less confusing. Link to post Share on other sites More sharing options...
shortliner Posted March 25, 2019 Author Share Posted March 25, 2019 Hi guys - sorry been off-line - I woke up this morning realising that , indeed, if the loco is stopped on the tracks over the magnets, reversing the power momentarily will not achieve anything - I need to apply a small amount of power in reverse as a quick pulse to move the kadees apart - - now thinking further! If anyone has any ideas, I really do appreciate the help Link to post Share on other sites More sharing options...
shortliner Posted March 25, 2019 Author Share Posted March 25, 2019 17 hours ago, ejstubbs said: Surely, if it's DC, you don't need the IRJs and all that malarky*? Just put the momentary reversal switch on the output side of the controller, before it goes anywhere near the track. Then there's no risk of shorts due to the loco bridging the gap between the normal and reversed polarity sections. * Unless, maybe, you're using common return? But let's not go there again... Yes, but therein lies the problem - the control knob is set to zero to stop the loco so there will be no power to the track via the pushbutton Link to post Share on other sites More sharing options...
long island jack Posted March 25, 2019 Share Posted March 25, 2019 (edited) Do as the real railroad do, just setback the power, sometimes they have sticky couplers!! Ray Edited March 25, 2019 by long island jack Link to post Share on other sites More sharing options...
shortliner Posted March 25, 2019 Author Share Posted March 25, 2019 (edited) I appreciate that, Ray, and it is what I have always done - but I was/am interested to see how this works/is possible. It would be nice to hide "The Jiggle" needed with magnets - I use skewers normally, and solve the problem that way, but to be able to do it "magically" hands-off, would be interesting and fun Edited March 25, 2019 by shortliner Link to post Share on other sites More sharing options...
ejstubbs Posted March 25, 2019 Share Posted March 25, 2019 The original author of the post you quoted (which seems to have originated on that cs.trains.com forum, not Facebook) appears to be still active on that forum. Maybe you could try messaging them through that forum to ask if they can supply details of their "cutting key"? And then share the info here! Quite an interesting layout he's built, as well: http://broadwaylion.com/broadwaylion.htm Link to post Share on other sites More sharing options...
shortliner Posted March 25, 2019 Author Share Posted March 25, 2019 (edited) Sorry EJ - the bit I quoted was on FB but it, as you say, originated on cs.trains.com forum - Someone is asking for me, as I'm not a member and it doesn't appear to let me post. I have found a possible email address for the originator (BroadwayLion) and have sent him an email direct - we'll see how I get on. Anything I find out will be posted here. Edited March 25, 2019 by shortliner 1 Link to post Share on other sites More sharing options...
298 Posted March 25, 2019 Share Posted March 25, 2019 2 hours ago, shortliner said: I appreciate that, Ray, and it is what I have always done - but I was/am interested to see how this works/is possible. It would be nice to hide "The Jiggle" needed with magnets - I use skewers normally, and solve the problem that way, but to be able to do it "magically" hands-off, would be interesting and fun I keep hearing stories and misnomers concerning Kadee couplers, but in reality all they need is to be properly setup with the coupler head and trip pin loop at the correct heights, and other influences such as steel weights and axles replaced on the stock in use. My best friends at the moment are TCSwowsound decoders, setting the throttle at a reasonable switching speed and pressing the brake function when the centrepin of the preceding truck is over the Railcrew magnet will stop the train directly over the uncoupler, and nicely free-rolling stock (ie without added brakes or any steel in them as above). A few cars for otherwise unknown reasons keep being kicked away from the loco during this move and it is possible to release the brake and have a successful uncouple without stopping at all. Link to post Share on other sites More sharing options...
shortliner Posted March 25, 2019 Author Share Posted March 25, 2019 Andy - thanks for that, but I'm DC - occasionally with sound via an MRC Soundbox - DCC+sound ( and decoders) are/is severely out of my comfort zone, which is why the heading includes the expression "Electrical Numpty"! Also, living the Far North, replacing wheels and axles/weights becomes a logistical nightmare. We manage with what we have. Link to post Share on other sites More sharing options...
Sol Posted March 25, 2019 Share Posted March 25, 2019 As I read all of this. I would drive the loco very slowly and as the coupler to be uncoupled passes over the magnet, hit the button to reverse track power making loco go backwards a millimetre or two, release button and loco continues on forward . now leaving wagon over the magnet- yes a slight jiggle/dance. But if pushing the wagon, as coupler is over the magnet, just reverse power from the controller to leave wagon in situ or if wanting to shunt it further, then use the pushbutton to momentary reverse track power making loco do the Kadee dance and the couplings have been set in delayed mode. https://www.kadee.com/animation/c1.htm 1 Link to post Share on other sites More sharing options...
RMweb Premium BR60103 Posted March 26, 2019 RMweb Premium Share Posted March 26, 2019 At Windermere there are magnets near the end of the station platforms. I find that I can usually drop the speed at the right point so that slack runs in over the uncoupler but the loco continues to the buffer stops. Tyco (USA) used to make a button that did the reversing bit. This was decades ago. Link to post Share on other sites More sharing options...
ejstubbs Posted March 26, 2019 Share Posted March 26, 2019 (edited) Just read the description in the quote again. I agree with those who say that, if the loco is stationary, then the controller will not be putting out any voltage for the reversing switch to be able have any effect. However, if the loco is at a crawl then the pushbutton DPDT reversing switch should/might work. I had a thought, though: what if you use a DPDT centre off switch? Bring the train to a stand in the right place with the switch in the 'normal' on position then, if the couplers don't uncouple as the train closes up on the loco (a bit like BR60103 describes above, or e.g. because the leading wheelset on the train is attracted to the uncoupling magnet), you could put the switch in the centre off position and turn the controller up a bit (exactly how much would need experimentation) then quickly flick the switch to the 'reverse' on position and back to off - giving you the minuscule jiggle required. Turn the controller down to zero again, then set the switch back to the 'normal' on position prior to moving the loco on. I think it should even be possible to source DPDT switches with one "on" position momentary so that it would spring back to the centre of position just by letting go. I've certainly got some SPDT on-off-(on) switches*. Aaaand...here we go: eBay item number 223458342565. (Other suppliers are no doubt available.) * By accident, as it happens: I ordered ordinary on-off switches but got sent on-off-(on). I thought they could come in handy so didn't bother complaining. I do use one for an isolating section at the end of a terminus platform. In the normal on position I have a diode in the circuit which means you can only drive the loco out ie away from the buffers. You can leave it in that position, or the off position, as a fail-safe in case you get distracted while bringing the train in to the platform. If you know you're paying proper attention then you hold it in the momentary (on) position while sidling the loco up to the buffers, knowing that you can simply let go the toggle to cut the power if you think you're about to run through the buffers. Or to save twiddling the controller knob if you're just being lazy(!) The (on) position also bypasses the diode so you can "do the Kadee shuffle" i.e. move the loco back and forth with it held in that position. Edited March 26, 2019 by ejstubbs Link to post Share on other sites More sharing options...
shortliner Posted March 26, 2019 Author Share Posted March 26, 2019 (edited) Thanks guys for the suggestions - when the bits arrive I'll try do set up and use your suggestions - no reply, so far, from Broadway Lion - in the meantime any, and all ideas are welcomed - EJ thanks for the link - I have just ordered 5 of these which may replace the push-button https://www.ebay.co.uk/itm/5-10X-UK-Miniature-6A-125V-AC-6Pin-DPDT-ON-ON-Mini-Flick-Toggle-Switch-Switches/173835857845?hash=item28796cafb5:m:mQiY_F4i0rzq1dhux07uaPQ Edited March 26, 2019 by shortliner Link to post Share on other sites More sharing options...
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