Kadee Couplers

Model Railroader General Discussion (Model Railroader)
1

What is the minimum radius on a curved track for the Kadee couplers to work effectively. I am building my layout now and of course would like to have magnets only on straight sections of track, but sometimes there is not straight section. Anyone ever figure this out. Thanks, Jim

2

Do you mean to have the delay feature work properly? Or just uncouple on the magnets.
Bob K.

3

Hello jim

Ok Kadees will work and stay coupled on most any curve radius within reason as far as uncoupling however they only work properly on straight track and will not uncouple on a curve never have or will as both couplers are being pushed to outside of car body in order for the coupler sto work properly they must both be centerd in the coupler box you can uncouple on a straight section then with the delay feature you can then pu***he car around the curve to your desired track or industry for spotting
if you must uncouple on a curve only way to do that is with a small pic or small jewelers screwdriver inserted tween knuckles then gently twisted apart other than that nobody i know or have seen makes couplers that can uncouple on a curve with any reliability
hope this is of help to ya
Larry

4

I have no problems with coupling on curves with Kadee’s. I run 18" radius. If they’ll couple on that, they’ll couple on almost anything.

5

I’ve found by experimentation that you need a straight section on either side of the uncoupling ramp at least as long as the longest car or engine you plan to uncouple there. If you use truck-mounted coupler (like on long passenger cars) then you can cheat on this rule a bit, but for body-mounted couplers, you really need those straights.

6

Ramp? Should the magnet be under a small ramp, say 1/8", or so in height?

7

The Kadee between-the-track magnets have a short ramp-like edge on them, so I’d imagine that may be where they got that name. I think the ramp-edge is to keep couplers from catching on the ends.

I mount mine flush with the rail tops, even though that means grinding down the ties a bit. This is lower than what Kadee recommends, but it keeps my P2K S1 from running aground when it gets to the magnets. It still uncouples just fine.

8

Thanks, Mr. B.

-Crandell

9

If the cars are 4 inches or under then a 6 inch radius works. At 5 inches long I think it is 8 inches if I remember rightly. That is for running only though.
As for uncoupling I have only been able when they are straight relative to each other.
Hope that helps.

10

Approx 3/8" diameter rare earth magnets (one under each rail) uncouple kadees on 30" radius curves just fine. The delayed feature of the Kadees works too and recoupling is OK too. Have not tried it on tighter curves.

These are small, unobtrusive, much more powerful than the kadee types, and far cheaper too.

Check around the web, prices vary.

11

Kadee couplers can be uncoupled magnetically on curves - IF:

  1. Radius is at least five times the length of the cars being uncoupled (assuming body mounted couplers.)
  2. The uncoupling magnet is offset so the couplers are centered over its center.

The delayed uncoupling feature only works if an under-the-track magnet is used. To get the necessary offset, a between-the-rails magnet has to be the narrow style, which doesn’t spread the couplers wide enough to keep them from re-coupling.

I haven’t tried this with electromagnetic devices or supermagnets, only with Kadee permanent magnets.

Incidentally, the old mechanical couplers (Mantua, Devore, Baker) used ramps between the rails to lift the uncoupling pins. Modern couplers aren’t lifted, but the name for the uncoupling device stuck.

Chuck

12

Ah, that’s the reason! Thanks.