When the cars are running down the course, they are free to take any line through the trough, but physics and the undercarriage mechanism cause every train to take a similar path in the u-shaped pipe. As the cars approach the three block brake sections, or reach the final brake run seen here, rails are added to the trough in order to corral the cars into the center of the track. This ensures that the car properly lines up with the narrow section of track that houses the pinch brakes.
©2014 Joel A. Rogers.