I have read many dream books and make attempts at dream interpretations, here is my take. I think that Terpy is very close to being correct.
The coaster train or (Mini Cooper) in this case represents you. Since you are not actually driving, this represents something you are not in control of like your job or school. As you are making your way up the helix (you being successful) this track breaking is a hurdle that you are going to have to conquer. There are no other routes to take, and you have no choice but to go through this (a difficult situation or decision.) Once you land you realize you not only made it without a wreck, you went to the top (success) and realize you can get yourself out as well.
The dream is telling you that you are going to go thought this and you will land on your feet just fine.
This is just my thoughts and I could be totally wrong, but I hope it helps!