Kadee uncoupling magnets

Discussion in 'HO Scale Model Trains' started by CAS, Dec 24, 2006.

  1. CAS

    CAS Member

    I have seen 2 different types of magnets for Kadee, 1 that goes on top of the ties, and 1 that goes under the roadbed.

    The magnet that goes under the roadbed, after glueing the ballast to the track. Is the magnet still strong enough to uncouple my rolling stock? The glue and ballast will that have effect on my magnets at all :oops: ? I was just thinking maybe the glue would interfer.

    Not sure on which magnet to go with.

  2. zedob

    zedob Member

    short answer, yes, the below the track magnets work fine. The trick is to place them where the cars to be uncoupled are in a straght line so that each coupler pulls away from the other without hanging up on each other.
  3. Russ Bellinis

    Russ Bellinis Active Member

    The other trick is to make sure you don't put any of the permanent magnets on any mainline. If the train pauses while going accross a magnet, cars will uncouple. That can be frustrating if you get a bunch of unwanted uncouplings.
  4. LoudMusic

    LoudMusic Member

    I was under the impression there was a button-activated under-the-roadbed uncoupler ... ? Maybe not from Kadee, but that someone was making an electromagnet uncoupler.
  5. pgandw

    pgandw Active Member

    Kadee makes an electromagnetic coupler (under the ties). You can also make your own.

    Another option is to hinge an under-the-ties magnet so that it slides or drops away when not wanted.

    The January 2006 Model Railroader has an article about using some cheap ceramic magnets under the ties.

    Some folks have vertically mounted small cylindrical rare earth magnets under or just outside the rails.

    The disadvantage of the last 2 methods is the shortened range that the cars must be spotted in. The Kadee magnets are quite a bit longer, which requires less accuracy in spotting the car to uncouple.

    my thoughts, your choices
  6. CAS

    CAS Member

    I am thinking about going with the under the track magnets.

    Would i install them before i ballast my track? or can i some how install them after i ballast.

  7. Gary S.

    Gary S. Senior Member

    Under the track magnets need to be installed before you ballast. Basically, the magnet is used in place of roadbed at the spot where you put it. Once you are sure everything is working properly, then you can ballast over the raodbed and the magnet.

    Depending on the thickness of your roadbed, you may have to do some shimming/sinking to make the magnet the same height as the roadbed.
  8. CAS

    CAS Member

    Thanks Gary.

  9. Pitchwife

    Pitchwife Dreamer

    Does the polarity of the magnets make a difference? + & - parallel to the track or perpendicular to it.
  10. Gary S.

    Gary S. Senior Member

    It does matter. The longest dimension of the magnet needs to be aligned with the track. The coupler pins need the proper orientation of the flux lines to make them open.

    If you haven't already, you should stop by the LHS and pick up one of each type of magnet and read the instructions several times. Do some playing around with them, set up a test track, and see what each magnet does. Get a feel for how they make a car uncouple, what it takes for them not to uncouple, etc. It would help if the test track is powered and you can do this with a loco, not just by hand.

    With the magnets, it is also vital that the couplers themselves are installed properly and have free movement and will snap back to center once they move past the magnet.

    The whole system is actually quite ingenius. Have fun!
  11. Russ Bellinis

    Russ Bellinis Active Member

    If you want to do as Fred suggested and mount the under roadbed magnets so that they a swung out of the way except for when you want to actually uncouple a car, then cut a hole in your bench and cork to allow the magnet to swing up under the roadbed to uncouple. Then cover the hole with a thin sheet of styrene, put your track over the styrene and ballast over it. Your magnet will be out of site, but when you swing it up into position, it will uncouple your cars fine.
  12. Santa Fe Jack

    Santa Fe Jack Member

    I like the electromagnet idea. Has anyone here built those? How many loops of what gauge wire would be required for 12 V DC operation?
  13. Pitchwife

    Pitchwife Dreamer

    What I do know: The amount of magnetic flux depends on two things, the core material and the number of turns that are wrapped around it. An iron core requires fewer turns to provide the same flux as a hollow core.

    What I don't know: Just how many loops of what gauge wire would be required. :oops: :D :oops: The wire will be the sole load on the line unless you add a resistor or a potentiometer.

    You might try finding 12v coils all ready made. It might be easier than winding them yourself. There are a number of sources listed on the Parts Supplier Page that you can access via the link in my signature.

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