I think we are all fairly aware of this, both of my Bachmann Class 08s have had problems over time.
The pick-ups seem to create grooves in the backs of the wheel flanges and thus they refuse to pick up sparky stuff from the track.
I have a solution.
Cut them off.
I have replaced them with 0.33 nickel silver wire touching on the actual wheel treads. It's invisible as well.
While I was at it, I always find that the keeper plate is to tight on the axles so I filed a small half moon shape out of it. You will see where the axle have been rubbing..
There you have it.