Spent a couple hours running a double loop with switches set up on the floor. Pretty slick! The track that came with the Hogwarts Express motorized kit has gray ties, but the track packs you can buy separately are a different color - Sort of brownish? The switches lock pretty tight when thrown. If I ran the train into the inside loop and threw both switches out, the train had no power - it was isolated! If just one switch was thrown in, then it had power. So power is directed by the switch as well.
Sounds similar to the old American Flyer switches in S gauge and how they operate.
If you want power to the inner track all the time or most of the time try using a toggle switch with a rating around ten amps to control power and use a second power hook up.
This is just like Hornby OO gauge standard Points(switches) work.
A siding is automaticly isolated when the point is thrown.
This is the norm in OO.
You could use another controler to power that track section independently.
Or you can get points in OO made by Peco that are non-isolating.
(Not sure about L gauge though)
I have not run DCC but I would think non-isolating come into their own when
using that system.
If you like Harry Potter check out the Hogwarts Express set made by Hornby.
www.Hornby.com
Regards
Nick