I am using uncoupling magnets by Kadee for passing sidings, yard trains, and industrial sidings. These are all under the track Kadee #308. I like the looks (or lack of same). [:D] But, my question is what to do with the mainline with respect to uncoupling magnets. Should I use the same Kadee #308 or the electromagnets produced by Kadee? There is a lot more work and wiring. Is it worth it? My layout is a little too “deep” (not shelf) to use manual uncoupling. What are your thoughts and experiences?
You don’t want to uncouple on the mains, in most cases, so permanent magnets there can be an inconvenience. They work pretty well, assuming that your couplers are properly mounted and the magnets located as specified, but they will uncouple whenever you’ve got slack. This can happen more often than you would think on level track, and if you happen to stop the train over the magnet, you’ve got to be careful of how it’s positioned.
I’ve got 3 Kadee electromagnets on my mains. As you said, they involve wiring and they’re more awkward to install. Once working, though, they seem to work pretty well, and I don’t get accidental uncoupling at all.
I had a lot of trouble finding the appropriate power supply. Finally, I was ready to buy the one from Kadee, but I looked up the same model and got it for half the price from Mouser.
I installed the first of these as a retrofit on installed and ballasted track. That was a lesson learned. The rest were done right - before the track goes down.
An alternative to the electromagnets is to hinge or slide the #308 so that it is not in the correct place to uncouple until wanted. Whether hinging or sliding is easier to accomplish depends on how your layout, roadbed, and subroadbed is constructed. Usually a form of fascia manual control is used to slide the #308 back into the correct uncoupling position, or up from the hinged down position.
Truth be told, it’s not a lot less work to mount a sliding or hinged #308 then an electromagnet, once the correct parameters for the electromagnet are established.
The far easier installation alternative is to use 1/8" x 3/8" cylindrical rare earth magnets installed as vertical pairs just inside the rails with tops at tie height. The downside is that the magnetic field is still permanently there, just like a #308. The big difference is that the uncoupling magnetic field is only in a small longitudinal range due to the almost point nature of the rare earth magnets. There has to be slack within a very small range from the magnet longitudinally to uncouple. This also means accurate spotting when intentionally uncoupling.
Instead of a 2"-3" uncoupling area from a #308, you have maybe 1/2" from the rare earth magnets.
I am currently experimenting with the rare earth magnets, as I don’t like the pre-planning and installation effort required for many of my #308 installs. Will say more as I learn more.
I use almost the same rare earth magnets as Fred. I however install them flat, one under each rail. Very small “pickup area” and only a few unintentional uncouplings (2 IIRC) in six years with well over a dozen uncoupling areas. I suggest marking locations with a person, sign or other means to aid in spotting cars.
One thing I had to do with the 308 magnets was replace all the steel axles on the rolling stock with non-ferrous equivalents. Certain very free-rolling cars with a steel weight would also cause problems. The slower the train was moving the more likely an unintended uncoupling would occur, but by removing all the steel the problem became quite manageable.
That early layout also formed part of a group sectional layout, and some of the “foreign” equipment would have steel axles. I found laying a strip of sheet metal on top of the ties over the 308 magnet seemed to absorb enough of the magnetic force that again the problem was controlled. There was still just enough power left that careful positioning could still coax the KDs to uncouple.
Where do you get the 1/8 x 3/8 rare earth magnets? I haven’t seen any that small and how are they aligned? I read somewhere that you have to have the poles lined up a certain way?
K&J Magnetics (http://www.kjmagnetics.com/products.asp?cat=13) is one reputable on-line supplier; there are many others. A search on rare earth magnets or similar brings a lot of results.
The magnets should be axially polarized, and you want opposite poles across the track. The whole idea is to generate a magnetic field horizontally across the track. The trip pins are simple pieces of iron, and are attracted to the strongest pole - which is why they are offset from center line slightly. The tip of the pin needs to move horizontally to the right (looking from above and behind the coupler) to open the knuckle.