use of resistor wheelsets in metal trucks : LUSENET : Wiring for DCC : One Thread

I have installed resistor wheelsets in the metal trucks on various freight cars and cabooses. I have been advised that this is inviting short circuit problems and that resistor wheelsets should only be used with plastic trucks. Is this true?

-- Otis McGee, Jr. (, June 30, 2003


Possibly. If you use metal axles, one wheel is insulated from the axle, and therefore is insulated from the metal truck. However, play in the axle may short the insulated wheel to the truck, though this is possible even without resistors. If the trucks are attached to metal that leads to the other truck, you may have problems if the insulated wheels are not on the same side of the car, again true with or without resistors. I really don't see any significant problem caused by just adding resistors, but maybe someone else has other thoughts.

-- Charles Lewis (, June 30, 2003.

We haven't seen this question like this on the forum before. Thanks for asking!

I agree with Charles. I do not believe that adding a resistor would add any problems with one possible exception. The axle the resistor is put on must be plastic.

Note: From an electrical standpoint, there is a difference between metal wheels, trucks, and axles that will impact the answer.

Metal truck, metal wheel, plastic axle: I see no problems you wouldn't have otherwise with metal trucks as Charles mentions.

Metal wheels, metal axle, any kind of truck: It is probably best to get a wheel and axle where the axle is plastic. If you tried to mount an SMT resistor on a metal axle, yes, you are inviting a short. If you try to solder a resitor to the wheels, you will likely melt the plastic insulator that is usually mounted in one of the wheels. Your resistor lead may also touch the metal axle inviting a short.

Bottom line: Any kind of truck, but I suggest you use a plastic axle.

-- Allan Gartner (, July 01, 2003.

Here's an update to my previous response. I needed some metal wheels for some new cars I bought.

Intermountain makes metal wheels with metal axles. They have the insulator in one wheel. This is just as I previously described and could be a challenge to mount a resistor to without shorting it out.

Proto 2000 makes metal wheels with plastic axles. These are the type that I suggest you use to mount resistors.

The Intermountain's are apparently very popular according to my hobby shop. In the hobby shop, I tested them in an Accurail truck against the Proto 2000 wheels. The Intermountain's rolled a TINY bit better than the Proto 2000. The Proto 2000's worked well, too, and I would be happy with either one. The Intermountain's cost just a few cents more. From the side, they both looked the same.

Since from the side, they look the same, you could put one Intermountain and one Proto 2000 on the same truck if you would really like to use Intermountains. We are going to make up a batch like this. It seemed to work and look fine in the store.

-- Allan Gartner (, July 05, 2003.

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