Bezier Curves -> RollerCoaster

Everything perfect with it, just problems in a looping

http://www.abload.de/img/achterbahn7wl7.png

how do i make the curve keep the form, and not rotate it
tried to tilt some parts, but that didnt work

Ah, the z-twist bug. If you do a search on z-twist you will find some answers. It is a known Blender bug that has been there for years and no one fixed it.

There are entire sites dedicated to work arounds, that is how famous this bug is.