Hello;
I have installed some in the track Kadee uncoupling magnets. I am using Atlas Tru Track and have cut out the ties were the magnets go and glued them in with the gluing jig. They work great but the problem I am having is when I pull a string of cars over the magnet the last car uncouples. They are adjusted with the track guage from Kadee. Any help would be appreaciated.
Bill
This is a common problem with the fixed magnet uncouplers. Usually when it is just the last car of the train uncoupling, it could mean three things. 1. The uncoupler is at the end of a grade so that the train is slacking up behind the locomotive. By the time the last car gets down, the slack pulls out of the train and the whip lash effect jerks away from the last car. 2. The last car is bobbing along at the end of a centipeding train. That is the locomotive will pull the car, the car responds by rolling forward but a bit too fast (Newton’s 1st combined with static cohesion). This effect works through the train and is magnified on the last car (mostly because it has nothing behind it to counteract the force). This causes slack in the coupler and if it is over the magnet then the knuckles open. In the old days, when cabooses were still used, one solution was to make the caboose not as free rolling as the rest of the train. Sort of like a slight brake action at the end. 3. The axles or wheels of the cars are steel. The magnet actually pulls the last car forward to its center faster than the train is moving. Once again causing slack and the car to uncouple. Once again a caboose can fix it. The usual solution is to replace all wheel sets with ones that have non-magnetic wheels or axles.
Well, I guess there is the possibility that it is a combination of the three things…
In the operating group I belong to, everyone (except one) of the layout owners have gone in and removed all the fixed magnet uncouplers. We now use the bamboo skewer method of uncoupling. One member refuses to operate on the one layout that still has magnets. My club is very close to the frustration point of removing them. When everything is perfect (coupler heights on all car
The other 2 magnets I have installed seem to be ok, I am going to reglue it in because it may have not been flat in the track,this could be the problem.
Thanks for the quick reply
Bill
One other possibility - the car might be weighted with a steel plate on the floor. The magnet will definitely pull on it! (I have a lot of steel - actually tin-plated steel! - 4-wheel freight cars, and they demonstrate this regularly.)
My fix was to arrange under-roadbed magnets that hinge down when uncoupling is not desired. The skewer method was considered, but there’s probably going to be catenary wire in the way once construction is completed.
Chuck
Sounds to me from this and previous threads that there’s no ideal remote uncoupling procedure for HO. I remember when growing up that my dad’s O27 set had electromagnetic uncouplers that magnetically retracted a horizontal disc from the coupler, causing the spring-loaded knuckle to open–worked pretty well, but obviously HO is prob. too small to reliably have that kind of a system, which is my guess why Kadee or some other mfg. has never devised it in HO. As a compromise, what does anyone think about the HO electromagnetic uncouplers–seems like this would eliminate the “last car” issue discussed here.
Jim
Kadee has an electromagnet that would work much int he manner that the 027 couplers worked. Nothign would happen to a train the ran over the electromagnet, stoppe dover, it, or reversed right on top of it is if was not turned on. Turn it on and the couplers will open like they do over a fixed magnet.
I installed a few fixed magnets on certain sidings, but most of my uncouplign is with skewers. If more cars had a universal coupler mount that was at the proper height (ie, you wouldn;t have to use shims and/or the Kadee over- and underset couplers to make them come out at the correct height), I would consider the Sergant couplers. But when I look at how many cars I had to do special fitments of Kadees on, not to mention locos - no two P2K locos are the same, Stewrat F’s use a special coupler, etc. - it would be a daunting task to fabricate coupler mounts for them all. Someday maybe the NMRA will look at this - in Europe they already have a standard couple mounting - NOT the same thing as a standard couple - a standard for the position of the coupler mounting area. Were this the case, you’d only need one style of a given coupler, instead of the dozens that Kadee currently makes. Substitution of whatever brand you wanted would be easy, since the heights would always come out correct.
–Randy