I couldn't figure out why the loco had a clicking sound. I had replaced one split axel gear and had taken the trucks apart looking for flash or something on the gears.....but no....it was a flat spot on the wheel itself.
The loco (a used one) arrived like this and I guess I missed the spot or maybe it was turned away from me whenever I had it upside down.
I dunno, looks almost like an arced spot or something had broken off, but it was flat and that's the basic I should have looked for.......where the rubber hits the road so to speak.
Interesting, I've never seen that before
That is exactly what it is, the wheel will constantly arc in that spot because it was not perfectly round from the factory. I have replaced a lot of Athearn wheels on my locomotives due to a flat spot just like that. One other note. Do you see how long the shaft is on the axle? I usually grind off a little bit of the axle ends with a dremel tool cut off wheel. It will give the wheels more freeplay and slack when traveling through curved track areas and will reduce if not eliminate the axle from riding and/or binding against the wheel sideframes.
Thanks for the tip on the axle ends. I never thought of that.
You know, that is probably another one of those endless things that make seemingly identical locos run differently. This axle is from a set of three "identical" locos, yet one of them "clicks" across a particular turnout and the others are fine....even though the wheels are all set correctly. Could be something like more lateral movement is needed.