Disney's in-house name for their tunnels is "utilidors"
Fun fact - they're not actually tunnels. They were built on top of the marshy Florida ground and high water table, and everything else was built up on top of them.
http:// land.allears.net/blogs/guestblog/2016/10/the_utilidors_at_magic_kingdom.html
https:// nypost.com/2014/07/15/dozens-of-disney-world-workers-arrested-in-child-sex-stings/