If you can get some old 6019 Uncouple tracks, or the more recent O-27 6-65149 Uncouple Tracks, you can cut out the center rail portion with the magnet and splice it into your Gargraves Track. I have picked up the old 6019 tracks from junk boxes at hobby shops for a buck a piece. I splice them into my O-31 Tubular track.
Steve