In a single coil-sized, humbucking hotrail, is there a magnet at the bottom, or are the rails themselves permanent magnets?

If the former, would magnetic rails work and how well?
Last edited by jimRH7 at Mar 20, 2008,
the rails are attached to the magnet by magnetism, making them an off shoot of the magnet. They already are magnetic do to the connection.
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