“The original design of The Beast had the upper and lower track in the helix on top of each other. In order to simplify the geometry of the crossover, the lower bents will be upper bents until the tunnel.”
Seems like a simple typo that should read:
“The original design of The Beast had the upper and lower track in the helix on top of each other. In order to simplify the geometry of the crossover, the lower bents will be separate from the upper bents until the tunnel.”