I like this idea, though I think that the sticky rails should have a bit more friction than normal rails (so that the minecart slows down more quickly than on normal rails). It just makes more sence to me like that.
I would love to have this in vanilla, it would make for some pretty cool roller coasters!
Still, I don't feel like this thing has a lot of practical uses in survival worlds... if one wanted to go down holes, they would make ladders rather than use iron and slime balls. But then again, this would be a pretty fun addition to the game
How? I can't imagine how the transition would go, unless you have slopes of each kind meeting each other, but that doesn't have the room for the player to fit through.
I guess they'd simply connect to normal rails in the same way as powered/detector/activator rails connect to normal rails.
And if you mean the horizontal to vertical transition, then it's probably simply putting powered rails on the wall, and normal rails on the floor (though sticky rails could be used for the floor as well), and the rails at the bottom of the wall will probably be at a 45° angle to connect the floor rails with the wall rails.