Kadee #308 Under the Tie Delayed Uncoupler

[bdh]

I noticed a similar effect you describe with the #308s during my workbench evaluation of all the Kadee versions -- above and under track.  About that time, the January, 2007 issue of MR showed up with Workshop article (p.40) suggesting uncoupling with some small, inexpensive magnets available at your local Ace Hardware store.  Wow, these work as well as the #308s!  On my "test bed layout" (eg., not permanent) I have installed them in several locations and find that they work extremely well and I have not experienced any "pulling" of the metal wheels/axles as I did with the #308s -- although some precision is required in spotting the cars to be uncoupled.  I should also note that all my rolling stock has been retrofitted with Kadee (whisker) couplers.  I determined at the workbench that "mix and matching" brands just didn't produce consistent coupling/uncoupling results.

[tomnugler]

I've been cutting them in half for years with no decrease in performance when mounted under the ties. Started doing it because the HOn3 cars are lighter and would pull up to the magnet. Spotting the cars is a bit more critical though.

 

Tom.

[wedudler]

I use the unter the tie magnets, too. But two magnets in one track give problems.

Therefore I've made a few of my magnets movable. This is helpful with two tracks. I can move the magnet from one track to the another.

 

 Wolfgang

[MisterBeasley]

Experiment with mounting the magnet further below the track.  If you've got it directly beneath the ties, try moving it under the roadbed.  It sound like the magetic field is too strong.  By moving it further away from the track, you'll reduce the field strength.

Set up a test track to do this.  You don't want to mess with glue, scenery and ballast until you find the right position for these things.

I've got a number of the above-tie Kadee permanent magnets, and they work pretty well.  I found that I had to mount them a bit lower than the position recommended by Kadee, because one of my engines (P2K S1) has very low clearance, and it ran aground on the magnets.  They still work fine down a bit lower.

I've also got one of the electromagnets on my main line.  It works well, too.  Since the track was already installed, I put the whole thing in from below.  Believe me, that's not the way to do it.  It would have been easier to rip up the track and just follow the directions.

[Lee 1234]

Try not using the steel intensifier plate.

[mrnimble]

Thanks, everyone, for your responses so far.  I'm not so concerned with appearance (of between the rails magnets) as I am with reliable operation as I do a lot of my layout operations with computer control.

[desertdog]

If your train hesitates over any permanent magnet uncoupler, you may end up uncoupling cars that you don't want to uncouple.  With experience, that should not be an issue.  I use the #308's in a few locations that are out of the reach of a hand uncoupling tool.  As long as the track is level and your couplers function well, false uncoupling should not be a problem--certainly not enough of a problem that you would want not to use them.

John Timm 

 

 

 

[ss122]

This may require more retro-fit work than you want, but you can try attaching the magnet to a hinge under the roadbed. Default position is down away from the rolling stock. Have a string, or cam or choke cable apparatus to raise the magnet into position when you need to uncouple. Ken

[locoworks]

those big magnets will even pull cars with metal axles and wheels. the ( expensive ) electro magnet is the only non visible way to go using AC so that you don't create a permanent magnet of the steel in it.   the between rails  version that sits on top of the ties is the cheapest compromise but can still upset metal wheel sets ( just ). you could look at putting that little spring MT produce on one axle of each car and that usually give enough resistance to prevent stock moving unintentionally.

[BlueHillsCPR]

I haven't used any uncouplers before but I have been looking and reading trying to educate myself in preparation for using them.  I have begun to think that using an electromagnet under the track is the best way to go.  Then you only have magnetism when the uncoupling switch is closed.  Just my

[mrnimble]

I've just installed a couple of these on a layout under construction (HO, Atlas 83) and preliminary tests show a distinct attraction of the strong magnetic field to the weights in my rolling stock which I'm now afraid will lead to erratic, unreliable uncoupling.  I've researched a number of older threads on this forum on this topic which is giving me further concern to the point I am wondering if I should go back to the between the rails #321 uncouplers I salvaged from my previous layout?   Does anyone have any recent experience and/or current comments on the practicality of using the #308 further?  I don't think I'm inclined to try to retrofit 50+ pieces of rolling stock with non-magnetic weights/wheel sets.  Thanks.