Oh Russ, I should have also mentioned that I did have a look at the traction tires on the wheels as you suggested. I found that the traction tires were not on the same axle of each truck but rather on only one tire of each truck. This meant that only one wheel of that axle was insulated by the traction tire at a time. As the other truck was the same, just reversed, it really didn't matter what you did to the traction tires as the engine was setup to get electrical feed from the extreme wheelbase. This seems to me to be a pretty smart idea compared to my steamers which have the traction tires on a single axle. It really appears to help this tiny switcher navigate the insulated frog turnouts.
Rob
Hampton, New Brunswick