Articles - Track: Throwing Turnouts Using Magnets
06/12/2020
External Reference:
Jerry Wilson has a very nice Sn3 layout under construction. In April 2020, he posted a video on his YouTube channel providing a complete overview of his layout. At about the 6:45 mark into that video, he demonstrates his use of rare-earth magnets for holding a turnout's position. I really liked that idea. It would allow for manual-throw turnouts, and it would eliminate the need for fussy Tortoise switch machine installation and tweaking. So, I placed an order for a package of those magnets (300 to be precise, via Amazon; they measure 2mm by 3mm). I contacted Jerry, and he mentioned that they are a bit fussy to get to work. But, my thinking was that all the tweaking would be done above the layout, rather than bending in awkward angles under the layout.
When the magnets arrived, I set about experimenting. This page does not present a clean and perfect solution. I am actually still very much in the experimentation stage, as I have not yet found a way to get two turnouts to work in the same manner. I will update this page in the future when I get it to work. However, I think this is a workable alternative, especially if you are interested in having manual-throw turnouts on your layout. I will take you through some of the experiments I've done and describe what worked and what didn't. Jerry had one magnet attached to the ends of his PC-board throwbar, and then a nail-mounted magnet set into his layout. I have most of my throwbars set so as to have a longer end on one side, so I thought about having just one magnet mounted to the long end of the throwbar, and then surrounding it with fixed magnets. Opposite sides of the magnet have different polarities, so this works, as my first quick experiment showed. The magnets were glued to the wood pieces and the throwbar with superglue. This worked, but the glue only lasted for a couple of throws before the glue gave out to the strength of the magnets.
Throwing Turnouts Using Magnets
I refined that idea by wrapping a piece of brass sheet around the magnet and the throwbar, and then filling that with superglue. On the fixed ones, I cut some styrene pieces, and drilled a hole matching the diameter of the magnet in each piece. I then reinforced that by gluing another piece of styrene on the "back" side. I determined how far the two fixed magnets should be away from each other and then cut a piece of styrene to match that distance. When that cradle was glued together, I determined exactly where it should be placed on the headstock ties, and drilled four holes through the cradle and into the ties. I then pushed four brass wires down the holes after I covered them in superglue. This made for a very solid connection. Of course, you have to be very precise with all of this to get the turnout to still operate as intended. I wasn't able to get it to work correctly, but I then re-soldered the point rails to where they worked correctly.
Throwing Turnouts Using Magnets
"Wonderful!", I thought, and believed that I had a solution that I could just replicate. Well, when I tried it on the next turnout, the force of the point rails was too great for the magnet, and so it wouldn't "latch". My point rails are solid rails as far as they can go, so I have the full force of a code 100 rail to content with. Jerry probably uses a light rail due to his layout being Sn3, and that may be why his one-magnet solution worked. I thought about it for a few days, and then came up with the idea of using two magnets; together they could overcome the force of the point rails. The photo below shows the solution I came up with. I drilled two holes in each piece of styrene (long enough to span the total width of the headstock ties), and then used five-minute epoxy to glue the magnets into the styrene. I reinforced that joint afterwards by applying some superglue as well. As the photo shows, the center styrene strip is mounted to the PC-board throwbar, and the other two are fixed in place to the headstock ties.
Throwing Turnouts Using Magnets
Thinking that now I had a working, repeatable solution, I set about to create that same structure for the next turnout. Well, it worked, but only for a couple of throws, and then the superglue joint broke. So, I carefully drilled a small hole down the piece of styrene mounted to the PC-board tie, and the tie itself, and then inserted a brass wire covered in superglue. You can see that in the next photo; the one on the left. So, on to the fourth turnout. Well, that one didn't have a long PC-board throwbar tie, so I had to come with with a system where it works more like Jerry's solution. I was unable to get the parts to stay mounted, and drilling the holes for reinforcing them with a wire wasn't working. So, I am currently trying a different solution altogether. I will update this page when I make more progress on this idea. I think the idea is sound; it is just that I haven't found a good works-every-time solution yet. The three that I have working, are working great. Due to the two-magnet solution, it sounds more like the old snap-switches, but I can live with that. When I do get a workable, repeating solution, I will deal with making them look more like automated switch machines as found on the prototype.
Throwing Turnouts Using Magnets