I purchased a 3086 SNCB P8 from a dealer in Netherlands some time back. Eventually I got around to testing everything and discovered a slight wobble. I removed the connecting rods and linkages to see if that eliminated the problem. Even without the linkages, the wobble was still present. I read old posts on the topic; many discussed removing wheels, etc.. One post recommended replacing tires, so I tried that.

I removed the old tires and tried the locomotive on my test oval without any tires. The wobble had disappeared! I mounted new 7152 tires on the locomotive and all is well. Pictures below show the locomotive, as well as a new tire (left) alongside an old tire (right).

Long story made short: sometimes the simple solution is the best.