Everything on model trains, model railroads, model railways, locomotives, model train layouts, scenery, wiring, DCC and more. Enjoy the world's best hobby... model railroading!
17 Responses to Uncoupling of Kadee Couplers – A problem
Leave a Reply
SUBMIT YOUR QUESTION
Download Your Free Catalog
Use Tiny Railroad Micro Controllers
Model Train Help Ebook
First check that couplers that have separated are at the right height, and if not fix that.
Also if undesired uncouplings tend to happen at specific places, see if there’s a vertical curve up or down there or a sharp sideways curve, and if there is then fix it.
Of course if the specific couplers are defective you need to replace them. Be sure to use good quality ones.
Could be several issues. 1-too many cars or too heavy of a train straining coupler spring. 2-verify heights-an offset will allow uncoupling on uneven track. 3-coupler knuckle springs get tired and loose strength. 4-make sure knuckle face is smooth.
Kadee makes a couple height tool. Get one and make sure your couplers are all st the same height
Besides the above good advice, remember that some older cars have metal bottoms or weights that can cause that car to ‘roll up’ toward the car in front of it when approaching a de-coupler magnet. This can cause it to release the load on the coupler that allows a ‘flex’ that can create an uncoupling. This generally happens on sidings, but if you have any uncoupling ramps on the main you could be losing half a train from time to time.
Use a Kadee coupler gauge to ensure the height is right and it is properly centred on the truck/wagon
Check your track for humps – not just where the uncalled for occurs – the whole mainline and major sidings/spurs. There might be an irregularity that starts the problem and another that brings it to conclusion. The best way to do this is to sight along the track towards a mirror. You’ll know the problem when you see it.
Lubricate your coupler knuckles and swivel with powdered graphite.
I have found that an overlong or heavy train will not cause couplers to open, but to break and fail completely.
I hope this helps
All these comments are very good. When running if a coupler comes uncoupled when a strain is present then there may also be another problem. Check your couplers if no problems then you may want to install a keep alive circuit in the locomotive. For the couplers to uncouple there has to be a break in motion. A keep alive will maintain motion by the loco.
You should also check that the spring pn the outside if the coupler is not missing. Also make sure the coupler springs back toward center when pulling the coupler back in each direction. If not, check the centering spring inside the coupler box.
There is helpful advice on the Kadee website: https://www.kadee.com/resources.htm
You fail to say what gauge you are using. If it is N Gauge, the light weight of the cars will make it uncouple. Kadee has however got a fix for this problem. A small spring (almost like a knuckle spring) is placed on the end of the axle, giving it a bit more drag and preventing uncoupling. All of the above apply as well. Coupler height, no slack in the train, etc etc.
First& foremost obtain a Kadee coupler gauge and both kadee red and gray washers. Check the coupler heights on each and every car in operation. Those that do not match the gauge set aside with a note high or low or no spring. Yeah a lot of work and smaller roster. If you are using talgo mounted couplers, you may want to invest in some of their offset couplers. They’ll also come in handy if/when you need more than 2-3 washers between the truck and bolster. I check wheel/coupler gauge on every new car being placed on my layout. You didn’t say if you were using scale or standard couplers.
RIX Products makes a uncoupler tool that I hook to a retractable connector, and I clip it to my shirt collar when I am operating my train. It looks like a square horseshoe with magnets on both sides. These magnets pull the couplers apart long enough to separate the cars. Great tool to have in your toolbox. Here is a link:
https://www.ebay.com/itm/293044874473?hash=item443ad5ece9:g:r9YAAOSwCKRcr43O
Occasionally, I have cars become uncoupled when the train is moving slowly across the magnet. there is so little tension on the couplers that the slack causes them to uncouple.
One of the side effects to having free-turning metal wheels.
If it is uncoupling at the beginning of end of a change in track elevation, you will need to make a more gradual approach to the change. On some cars, one coupler may be riding over, or under the other, causing the uncoupling
One cause not mentioned here is the height and angle of the coupler pin. The same kadee gauge has a shelf for checking its position. If the pin is too low or angle to the side, any obstruction between the rails like road crossings or turnout frogs and guard rails will cause uncoupling or derailments.
wonderful input. thanks to all!
If you are decending an incline sharply, and suddenly you get t the top or bottom and level off, this is the point where the knuckels on th ecouplers may go out of alignment and slip apart.
Also if you are interfacing to different pieces of track, perhpas the rail head height is different, the as the knuckles pass over this area, they may misalign. Dropping from a higher rail head t a lower one is a bit like going “downhill”, it becomes more sever in ascending this difference, causing a possilb ebump and the knuckles could shake apart. If there is a car with this problem on one end, give a go at turning the car around and checking if the problem still exists.
Coupler height issues can cause this. Otherwise, look closely at the couplers in question and ensure that the spring is there. If it isn’t, replace the coupler. Also make sure that the knuckle moves freely and isn’t stuck.
Rough trackwork can also cause couplers to malfunction.