unique track piece

I found this unique track piece from a lot if acquired awhile ago. Does anybody know which set this came from and the purpose of this unique piece?

@[deleted], That piece is from the castle quest set.

Here is a link to a video that shows you how that piece works.
https://www.youtube.com/watch?v=ddxGvTfnqgY

Thanks GG-Fan 🙂

thank you