Hello everyone. I guess I am going to call this question a NOOB question for sure, but it has me puzzled. While testing some resent rolling stock and engines I acquired, I notice several of the rolling stock had metal axles, then I wondered how that works without shorting the track out…It did not effect my engine nor the fault indicator light never came on the control box. Are the wheels some how insulated from the axles or what?
Jeff
Hello Jeff,
Yes, usually just one of the metal wheels is insulated from the metal axle. The most common insulation is a small plastic bushing between the insulated wheel and the axle. Look closely and you’ll probably be able to see this.
So long,
Andy
I have seen some wheel sets that had a plastic bushing on each wheel. It really depends on the manufacturer and where they get them.
I have just recently gotten a couple of cars that had steel wheels and steel axles in HO. They look like they were nickel-silver plated, but the un-coupler magnets sure sucked them in. I had to check with a magnet just to be sure it wasn’t the car weight causing the problem.
The easiest way is like the old Athearn and Roundhouse cars. They simply have plastic wheels. But when the wheel is metal there is always an insulator on at least one of the wheels. Most of the times there is a small bushing right around the axle hole. Take a look with a 10x loup and it should be visible. Other manufacturers have plastic wheels with metal “tires” on them.
Wheels with insulation on one side work just fine in the vast majority of cases. However, there are instances when you do want both sides insulated. If they are metal trucks and will be used under brass or other metal rolling stock, then the double insulation on the wheelset is additional insurance against a short.
The way a wheelset is insulated comes into play with other features of some layouts. If you run lighted equipment, then the wheelsets need to be set up right to get the current where you want it to go. Similarly, there are some layouts that employ resistors or other devices on wheelsets to support occupancy detection. But these are special instances where a little thought is necessary about a specific application.
Keep in mind when experimenting with wheelsets that they are not all the same length. Some can be interchanged and some not, so remember to keep them matched up, rather than mixed up, when you have a truck broken down into its parts.
I have some older Athearn passenger cars and one wheel is metal, the other is plastic. If they have the brass strip attached to the center of the truck, make sure that the plastic wheels are on the same side of the truck. With this setup, the metal wheels are on one side of the car in one truck, while the metal wheels are on the opposite side of the car in the other truck.
Some of the very old Athearn all-metal trucks used a coating of a sort of reddish varnish to insulte the wheels. As I recall it was just one wheel – and of course you have to have all the insulated wheels on the same side when metal axles and all metal trucks were screwed into a metal frame. And even more complications arose when that all metal frame had the all metal couplers at the end because now you had to worry about creating a short when you coupled to another car or locomotive.
And over time that reddish varnish (could it have been finger nail polish?) could crumble away and fail and then you had a potential, and very difficult to trace, short circuit.
Walthers for years had trucks with what looked like a brass axle and plastic wheels. Back in the day Mantua had plastic wheels on a steel axle but that posed its own problems because the Kadee uncoupling magnet tended to attract (or repel) the steel axle. Sometimes you’d see a car seem to “tremble” all by itself and it usually was a case that it was parked over a Kadee magnet.
Dave Nelson