I see you noticed... I had to put breaks in certain spots of the coaster to make it run smooth without going to fast. Like in the tunnel, those keep it from flying into the station to fast, and the break at 1:55 keeps it from hitting the mid-breaks to fast. In real life they would have put them on the hills and stuff.. but that's not possible with Rct3.
So basically I created my own trimming system.. and by the way.. I had a corkscrew instead of the tunnel originally, but it didn't come out right, so I had to re-make that part, and so I ended up putting a tunnel there.
I hope everything sounded clear.