This is just off the top of my head, but it's much like a slot race car. It just follows the slot in the center, but a computer is able to track where all the cars are. One car can go 60 mph while another is stopped since the computer knows the positioning of all the cars. This is what makes the ride systems often go down, especially Test Track. If one car malfunctions, the ride has to stop. The system works pretty well though, especially in later iterations I.E. RSR and Journey. Oh ya, and Test Track is definitely the fastest of them. As for manufacturing, I dunno.