Resistance wheels
Sep 18, 2016 Filed in: Rolling stock | electronics
If you want signaling on your layout (and who doesn't!), you will need some way of determining block occupancy. I use Bruce Chubb's Optimized Detectors, when are a current sensing-type detector, and they have worked flawlessly on the Mighty MKT for years.
The current sensing detectors can sense the locomotives in a block, but for cabooses and rolling stock, you need to add a resistance wheels set or two on the car to create current path that trips the detectors. We do that by adding a small (and I mean small) surface mount resistor across the axle and the gap on the insulated wheel. The current path is completed using conductive paint.
Step one is to layout out several wheels on some masking tape so you can apply the conductive material. You then place a very small amount of CA (superglue) to the insulated side of the axle, and gently place the resistor on the glue, angled across the gap between the axle and the metal portion of the insulated wheel.
After the glue dries, you can then use a fine pick or needle point to add a very small dollop of the conductive paint, first to the wheel side, then to the axle side. In N scale, this is very precise and tedious work, since you need to make sure not to cover the entire resistor with paint, nor submerge the resistor in the drop of CA. My buddy, Joe, is MUCH better at this process than I am.
If you look closely, you can see the axle side of the bottom wheels covered with the conductive paint.
For years, I put conductive wheels only on my cabooses, and used software to "detect" short blocks on the layout. I do not detect the turnouts individually as you would need to do on a full-blown CTC layout. My goal is to gradually add resistance axle to every car 50 ft or shorter, and two (opposite side) axles on all cars longer than 50 ft.
I bought a package of 100 wheels from Fox River Valley, which is a good start toward my goal of at least one detected axle per car on the layout. Three or four more packages and I can call it good!
The current sensing detectors can sense the locomotives in a block, but for cabooses and rolling stock, you need to add a resistance wheels set or two on the car to create current path that trips the detectors. We do that by adding a small (and I mean small) surface mount resistor across the axle and the gap on the insulated wheel. The current path is completed using conductive paint.
Step one is to layout out several wheels on some masking tape so you can apply the conductive material. You then place a very small amount of CA (superglue) to the insulated side of the axle, and gently place the resistor on the glue, angled across the gap between the axle and the metal portion of the insulated wheel.
After the glue dries, you can then use a fine pick or needle point to add a very small dollop of the conductive paint, first to the wheel side, then to the axle side. In N scale, this is very precise and tedious work, since you need to make sure not to cover the entire resistor with paint, nor submerge the resistor in the drop of CA. My buddy, Joe, is MUCH better at this process than I am.
If you look closely, you can see the axle side of the bottom wheels covered with the conductive paint.
For years, I put conductive wheels only on my cabooses, and used software to "detect" short blocks on the layout. I do not detect the turnouts individually as you would need to do on a full-blown CTC layout. My goal is to gradually add resistance axle to every car 50 ft or shorter, and two (opposite side) axles on all cars longer than 50 ft.
I bought a package of 100 wheels from Fox River Valley, which is a good start toward my goal of at least one detected axle per car on the layout. Three or four more packages and I can call it good!