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Ken,

Sorry to hear it didn't work for you. I suspect the recipe was not followed exactly. The only fellow I have heard from who had a similar problem to what you report, had fairly lightweight rolling stock where the magnet strength was greater than the car's inertia. The solution there was to coat the magnet with either epoxy or high voltage varnish that is used in electronic applications. The coating cuts down on the magnet strength.

My friend Matt Forsyth also added a file to the yahoo P48 group site files that has a further explanation and excellent photos. Try the coating and if it doesn't work, I'd be glad to take the magnets off your hands.

Regards,  Ben

Big Jim;

Most magnets will work, the critical thing is not the magnet but the spacing of the magnet to the reed switch. Got to get it close. Very Close is better.

Magnetic force drops off very fast over distance. Much faster than the standard radio propagation of double distance = 1/4 the power.

More like logarithmic or parabolic curve dropoff.

Jim,

The magnets are extremely powerful. I suspect you would have to try a few samples for your application. Take a look at the variety offered.

http://www.kjmagnetics.com/

The ones I used for the air hoses are 1/32 thick and 1/16 in diameter.

The type that you presented on the video is intriguing. I tried to look, but apparently the company does not have a website and do not have a product description. The whole idea is basic physics and many parameters must be met to achieve good reliability. Playing with magnets is pure fun. 

Regards,  Ben

 

Ben & Russell,

Thanks for the info.

Keeping a magnet thin enough to mount to the back of a driver and clear the frame is of first importance and then mounting the reed switch close enough to activate the circuit.

 

Ben,

Have you ever dabbled in using magnets mounted on engines and cabs to operate road crossing signals/gates?

Jim,

I do not use magnets for activation of my signal system. I would assume that would be difficult to control. Instead I have always used Integrated Signal Sytems solid state electronics, very reliable.

Note that you have started a new thread, so if you wish to talk signals further, you need to change the subject title.

Regards,  Ben

I'd like to summarize some things about this idea. When the idea was first published in O Scale Trains back in 2009 I had done quite a bit of experimenting in order to select materials that worked well. That is still my recommendation. If you choose to deviate from the recommended materials, you are on your own.

There are several resouces now on the web. Dave's blog up above shows his experience. Matt Forsyth's work as well as my own are in the Files section of the P48 Modeler Yahoo group.

As was noted above, while prototype in appearance, this idea is not for everyone. If one is using the Kadee couplers, the curved steel pin must be cut off. This then means that the couplers must be uncoupled by using a manual pick from above. This is not easy to do if the couplers are any distance away. Old guys with bifocals take note. In general then this idea works if the uncoupling zones are near the layout edge where one can both reach and see. As I indicated above, I was after a complete system which included coupler choice. One reason I chose the Protocraft design was that I could uncouple them using a magnetic wand that did not have to contact the coupler body.

The magnet strength is a key to success. Folks who have used other than what I recommended often have problems in getting the hoses to release without moving the uncoupled car. The air hose material is essential. Chris mentioned stripping wire insulation material. While trying to be helpful, I doubt if he has actually tried this idea. Wire insulation varies greatly in resiliency and I don't think you will ever match the softness of the Larva Lace tubing. The LL tubing also has a natural curl which looks good and can be biased toward the track centerline. Matt Forsyth mentioned this in his experiments. Length of the tubing is also important to achieve proper action. Cars usually are in the 5/8ths range, locos are sometimes shorter. It also depends on car length.

I usually use both brass angle cocks and glad hands because they look great and are also included with the couplers that I purchase. The magnet is glued into the pocket of the glad hand with a good quality ACC such as Sinbad. I've never had one come out. The original article showed an alternate of simplying gluing the magnet on the end of the hose and then overcoating the magnet with epoxy to make sort of a nondistinct blob. This also works but is not as sharp looking.

As was mentioned above, if the magnets are oriented face to face and the polarity is correct, they will join face to face. However if the polarity is opposite, the magnets will still join but will meet edge to edge. At a normal viewing distance this is not noticeable, but some will object. I once had a manufacturer contact me about the idea and then he decided against it due to the potential complaints about the occasional mismatch. He seemed to feel that model railroaders are a somewhat complaint oriented bunch. Imagine that!

Regards,

Ben Brown

Ben,

Thanks for the run down.  I read your article in 09 and it stuck in my mind as something I wanted to do.  Before the article I already cut the "air hose" off of the Kadees because I thought it was a terrible representation of an air hose.

 

A few years later my local hobby shop starting carrying the magnets I purchased.  To be truthful I never went back and looked at the article just plowed forward with the project. 

 

I am going to go back and pick up a package of the magnets you have recommended and try again. 

 

Thanks again for the great idea

I installed Ben's self coupling air hose's on 4-Lionel Milk cars. I keep these cars as a set and like the look. I had similar problems with the magnet pulling the car but once I added weight (Ben's idea) to each car they work well....With the cars run as a set, I don't have to worry about magnet polarity. Personally, Ben's idea is a good piece of Imagineering

 

Thanks Ben...

 

Dennis 

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