While merely speculating, it appears that the contractor that switches the industries on both sides of the CSX main failed to properly insure that one of the switches on the main was restored to "normal" (mainline movement) position, yet reported that all switches handled were restored, as required by CSX rules and Federal Law.
reporting a misaligned switch... http://www.inquisitr.com/2781092/in...-multiple-train-cars-to-derail-in-marysville/