Purchased ten years ago, from a used set breakup.
All four drive wheels are "ribbed". It runs fine but sounds like a sewing machine on the track.
The manual I downloaded doesn't mention traction tires or the "ribbing".
Is the purpose of the "ribbing" traction? Have not seen other locos with this.
I installed traction tires but of course that insulates the outside rails and it won't run.
I could leave 2 traction tires off, which reduces the sewing machine noise, but also impacts operation, is there another solution?