I do have the occasional short circuit. The original Wasatch UP passenger trucks have a glitch. Some of the early PSC Pullman and Harriman passenger trucks also have a glitch. A Lobaugh truck with a bent bolster will short. I have seen driver brake beam shorts on just about everything, and once in a while a side rod will touch an insulated rim, or a lead truck will touch a cylinder block. And the PSC CB&Q Hudson had tender trucks with shorts that I simply refused to tackle for any price.
This is not a problem for plastic models, so no wonder HO doesn't have short circuit problems. And if you run metal wheels on your freight cars, go with the plastic box Kadees. I pestered them for two decades, then somebody else got them to produce the metal coupler/plastic box couplers. Hope that guy gets them to do O Scale trucks some day.
Please do not repeat this post - it is copyrighted. Opinion.