Preserving Magnatractions on RailRax

Lately I’ve been concerned about my display postwar pieces and their magnatraction. I’ve always read about completing the magnetic circuit to keep them lasting longer. Today I tried slipping 2" long finishing nails in inconspicuous spots across the axles while the locos are on the railrax. Did this with my F3, NW2 and 681 turbine.
You can’t really notice the nail heads very much but does anyone think this will really help or is there a better idea out there?

thanks,
Mike S.
Saint James, NY

These permanent magnet fields can’t be “preserved”. The field is being generated by the electrons in certain orbital shells all spinning in the same direction. The use of a magnetic material to “short” the magnetic field will keep the loco from picking up extraneous debris so it is a worthwhile endeavor.

If the magnetraction effect is weakening on a loco, the magnets can be “refreshed” by use of an induced field like the one used to magnetize the material in the first place.