Charles,
Dave has shown you one of the easiest way to bridge an access point.
He shows pins but they could easily be large nails in snug holes in the plank. I would also and a weight (or strong magnets)underneath to to keep the plank in place. After you fit the plank in place and are happy with it, add the track. Add power wires, either soldered fixed or with plugs. The plank DOES NOT have to be rectangular. You can contour it to align with naturally occurring track joints if you are reluctant to cut the track.
I need to take a few pictures of by TEMPORARY swing up bridge. It's only been in place for 14 years.
Jan