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Kadee Coupler Uncoupling Problem
It is good to see so many beginners joining the hobby – that’s exactly what this hobby needs to continue long into the future. If you are experienced in the hobby, I’m sure you’ll agree, we should all be doing as much as we can to encourage and help them along the wonderful journey they have ahead. If you are able to share your knowledge then please do so by using the ‘Comments’ tag below each posting.
Anthony asks readers:
“I am a newbie to model railroading and use HO Kadee couplers, but I am having lots of trouble with cars becoming uncoupled during operations. Help from anyone please.”
16 Responses to Kadee Coupler Uncoupling Problem
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You don’t mention under what conditions the uncoupling occurs. here are two scenerios.
If the train is uncoupling at either end of a steep grade then the couplings must be lifting out of each other, try to smooth the transition at each end of the grade. The same thing can happen if rail joints are not level.
If the coupling is plastic it may bend and pull apart with very heavy trains.
Robert
Get yourself a Kaydee height gauge ,solves all problems height wise
I am wondering the same thing. I have the Kadee couplers, and the magnetic knuckle couplers. I even have having problems with my Kato Metra cars, I am positive that all my couplers are at the same height, and I don’t have any grade changes. Any help for either of us would be greatly appreciated!
The problem could be couplers at differing heights. KD’s come in three settings on the shank High, Centre and low a KD gauge is a good investment to make sure all the couplers sit at the correct height also make sure that the bent wire that works on the uncoupling magnet does not contact any rails as this can also be a cause to your uncoupling problems. Hope this helps happy railroading.
had the same issue. filled in spaces between track sections and bought a coupler height gauge. if that doesn’t work take a single paper staple, bend into a circle and hook it around both the couplers. never come apart until you unhook.
Almost for sure the coupler heights are at fault. Make sure you use a coupler height gage and set the waggons etc on a piece of track which you can look at eye level to see how the couplings line up with each other. To lower a coupling put a bit of packing underneath the coupler box, or you can buy offset couplers which have the coupling head above or below the centre of the shaft. If you wish to raise the coupling carve away a little of the floor until the couplings align.
I am probably telling you “howto suck eggs” but that is what I do anyhow.
Make sure that the couplers are at the same heoght. Get a Kadee coupler height guage. You can adjust tne height with Kadee washers. Also, make sure that the trip pins are not catching on turnouts.
I not very experienced yet, but trip pins can catch on turnouts and result in uncoupling and derailing…bending the trip pins a little to clear the turnouts did the job. Special trip pin pliers are great for this job.
Also experienced was a track gauge issue. HO Flex-track used in a curve would not hold the gauge at a rail jointer. Since gauge became slightly narrower at the rail joint this caused the car to raise slightly and resulted in uncoupling. This has not been fixed yet, but the solution planned is to uninstall the track, solder the rail joiner while that tiny section of track is straight, then re-install the track.
It sounds like coupler height mismatch. Purchase a coupler height cage and check and correct
as necessary.
Hi Anthony, your problem is more common than you may think. Almost 100% of the answer from other members mentions the correctness of the coupler height as the cause and solution. This is true, of course, but, believe me, there are two other big causes: small humps in the layout may be the cause, specially with long passenger cars, to “bend” at that point causing the uncoupling. I had this in my own layout and had to correct them to almost eliminate this cause. Note that it is almost impossible to build a perfect leveled layout at once. Also, even the track contraction/compression due to temperature changes may cause the perfect leveled track to creat small “humps”, almost imperceptible. Look to them carefully.
The other big cause is the overhang of the car ends in small radius curves. Look carefully as your train is rolling and stop it at once when you notice the uncoupling. Look if it happens in a curve, even in a switch. Gently roll the two uncoupled cars by hand.and see the results.
Try to use same type of coupler in all your locos and cars (I decided to only use kadee and nothing else. In new locos I trow all McHenry couplers in to the trash can imediately after opening the box.!
Hope I could help. Enjoy the hobby!
It could be the couplers height is misaligned but it could also be that the train is too long (too many cars) or that the cars themselves are either too light or too heavy. If I recollect the cars should way about 4 ounces; less and they’re suseptible to any and all bumps in the track and hop around, more and they simply pull apart.
Something not mentioned in these responses is that in model trains, unlike the prototype, the couplers rather than clothes lining under stress, will slip either up or down and disengage. The primary way to remedy this problem is to assure that the coupler boxes do not allow the coupler to droop when slack. The cure for drooping couplers is generally a thin shim placed under the coupler shank where it exits the box. Another problem I have experienced is slack in a train where it passes over a magnet, such as at the bottom of a grade. Here, the solution will be customized. .
It could also be that the tiny springs in the couplers have fallen out.
Your couplers can all be at the right height but many cases the the trip pin will drag a rail of a switch even if you set it with a gauge. I set the trip wire to curve up a little so that any rail it might come in contact with will just lift over the touching rail.
My longer cars I have gone to the Kadee 118 double shelf couplers as those couplers really stay together. long passenger and 85 foot flat and auto box cars including Walther autoracks will stay together. If you are running on changing grades or on an older modular layout the module will droop between the legs and a standard Kadee # 5 will walk out of each other as they cross from module to module. Kadee 118 or 188 wisker couplers are a positive lock and you need a magnet to release them or a coupling pin tool. They really hold Other brands of shelf couplers look good but do not actually work I am changing grades and turns in turns too. from Newman
I enjoyed reading this string as I have just designed and built a specialist “shunting yard” layout which has a long head shunt with 2nd radius curves and then 15 switches or points in to the individual sidings. i chose Kadee style couplers and installed them on my shunter ( a Class 08 ) and all the lead wagons of a set of cars. My problem seems to be that I can unhook over the delayed action magnets but when I push back through the curve and then the points to the sidings the hard right turn causes the hooks to re-engage and therefore are connected again. It could be due to the fact that the Class 08 has a rigid coupler system rather than the ones that move with the bogies on the larger locomotives.
Any experience here anyone can offer would be welcomed
Also when using the Kadee couplers suitable for the NEM pocket application how does one adjust the height?
I had the same problem with the cars coming apart.
I would check where at on the track, that they came apart at.
The switches, the pin wire of the couplers would hit, Bend the pin wire up on the
cars. That solved that problem.
Next when the train is going around on the Layout, Check to see if there is any uneven
track spots, like Rail joints or on the Grades and wherever there is any Uneven track
spots.
I also used Kadee couplers #118 SF. They are all metal and they do work, Good.
Also get a Height Gage too check Your coupler Height.
Tim Happy Modeling