Eradicating wheel sound.

Depends what loco you are referring to i suppose. My experience of the old mainline warships was they all did it up to the point where the drive gears on the axles wore a bit and the motor just sat there spinning. Could be a tooth or 2 missing from one of the gears or a worn mechanism. Give us a bit more info and someone may be able to help.

It is certainly a puzzle, I have two models of the Warships a green and blue colour and both bought as new in the late 70s.
A thorough clean of the green model certainly stopped noise emitted while traversing over the track, while the blue coloured model still emits the sound.
Arrangements of the electrical wires around the motor itself if not correctly carried out, can restrict side movement if wires are not place above the motor casing.
Fleischmann's sales representative has indicated to me that cause of noise being generated by a faulty tyre - the Warship power bogy is fitted a tyre to each of the four wheels. I have contacted several authorized Fleischmann retailers for replacement tyres - no success so far for a reply.
Is tyre replacement an easy operation?

Tyre replacement isn'y usually a difficult job just make sure you do it in a confined space in case a tyre decides to launch itself across the room. Very annoying and always difficult to find.