John, Magne-traction was developed by Lionel on the 622/623 model locomotives. I believe most 623 locos use frame magnets, not axle magnets. When Lionel built a locomotive, they magnetized the truck after it was assembled. The only person I know who had the equipment to magnetize a Lionel truck was Denis Waldron. Denis dies last year and I am not aware that anybody has taken over his business. You might look for a magnet person, rather than a train person, to see if they can help with remagnetize your locomotive. First you may want to check that your loco was a truck frame magnetic arrangement and that the magnetic are there. These should be one magnetic glued into a recess in each end of the truck frame on top. These magnets are available.
If it turns out that your locomotive does have axle magnetic, Jeff Kane, The Train Tender, has reproduced then. You could give Jeff a call and ask him who he might recommend to change the axles. Changing axles does require some special tools to pull and reinstall the wheels. On the 623 getting the worm wheel off and back on the axle can be tricky.
