I’m pretty sure it was an idea from RR_Mel (Melvin Perry) but using the MR forum search I can not find the original thread!
Thanks, Ed
Well that tells my age LOL. I bought it brand new in the late 1970s I believe. Still in great condition and works as well as when I bought it.
There are many articles on track cleaning in my model railroad magazine library that dates back to the 1950s. I’ll have a look there and post my findings.
By mixing fast-drying wood glue with shale particles and magnetite powder, Rusty Steele and Sons, Ltd. (the name of my HO scale metal scrapyard) makes large blocks for building foundations and retaining walls. This type of block, one of several Steele products, is attracted to magnets because of the embedded magnetite. This morning I glued a small piece of ceramic magnet that I broke yesterday to the feet of an HO scale seagull. The seagull-on-ceramic-magnet (that looks like a rock) can now be moved anywhere in the layout where there is metal.
Seagull standing on his favourite rock. I can move the gull anywhere there is embedded magnetite and he won’t easily fall down.
In order to incorporate magnetite as a sensor component, its electrical properties need to be understood. In this photo you can see that a continuous electrical path exists between the ohmmeter probes giving a near-zero electrical resistance. In other words, as already mentioned, the magnetite is an excellent electrical conductor.
When two magnetite layers are separated by a dielectric (the hard brown stone in the middle may be the mineral jasper) the sample may exhibit electrical capacitance.
Indeed this sample has a capacitance of 0.015 nF (nanoFarads). It may be necessary to take this type of capacitance into account in some circuit designs.
Designing sensors that actually do neat things will take some design and testing work so I’ll wrap up this thread with a few pictures showing you how Rusty Steele and Sons Ltd. embed pieces of magnetite in their block products. This is one in progress that they started last night. First they dip into their stock of processed red and grey sandstones, shale, coal, and gypsum - all gathered from field trips in and around my real layout area on/near the Bay of Fundy.
In this case the company is making a concrete block out of Windsor gypsum particles. Three grams are measured.
Next they add 2 grams of LePage quick dry wood glue.
A gram of Cape Blomidon red sandstone is added as a filler. Colour doesn’t matter for this block because it will be painted in a concrete colour after it fully cures.
The ingredients are thouroughly mixed until the wood glue begins to get a little sticky.
Four pieces of magnetite are embedded into the block on the top of an initial layer of ‘concrete’ mix.
Finally, a top layer of ‘concrete’ mix is applied. Note that the block is sitting on a piece of paper from stickers - easily removed later.
All ready to paint today. Did I mention the company can also make yummy-looking fake Oh Henry bars (this one not HO scale)? End of thread - thank you. P.S. Will look up track cleaning articles in my model railroad magazine collection today.
Oh, there is one last thing I can post in this thread as I begin to design sensors for animation. This is my magnetic test car with 72 ceramic magnets attracted to eachother and to the metal car floor. They are not going to move no matter how fast the train goes.
I live in northern Minnesota where magnetite is mined for iron ore, and magnetite dust is mixed in with everything around here. My advice, from personal experience, is that magnetite and model railroads do not mix, no matter how well it is secured. The magnetite particles and dust get into motors and anything else connected to the motors with a steel shaft. Don’t do it.
If you need the sparkly black, use some other non metallic mineral. If you need the magnetic properties, imbed a piece of steel.
It’s good advice but that is what will set my layout apart from most others. All my loads will be real Nova Scotia materials. Real materials will be used in structures and ground cover.
I have been running a lifetime trial for four months now using many unprotected real Nova Scotia loads in open hoppers and gondolas. These loads include gypsum, magnetite, barite, scrap metal, coal, ocean driftwood, and soon pyrite. Two DC trains have been running pulling all of these cars plus an assortment of other car types. I have had loads spill onto the tracks and cleaned up without any noticable degradation in train performance. This lifetime trial is set up in its own location and will continue indefinitely using the two dedicated locomotives. So far not a single problem.