I recently purchased a used "Track Pack" and of course it has no instructions.  The kit contains a magnet.  Does anyone know what the magnet is used for?

Thanks.  Seems I wasn't given a complete set.  Seem to be missing the A/B pieces.  Oh well.

I was given the track and bumpers from an auto reversing kit in HO scale.  How do I get power to it?

Where can I find G Scale plastic track for Bachmann trains?  What about plastic switch tracks?